Revert "Revert "Merge pull request #17637 from jacobly0/x86_64-test-std""

This reverts commit 6f0198cadb.

lib/compiler_rt/addf3_test.zig

@@ -4,6 +4,7 @@
 // https://github.com/llvm/llvm-project/blob/02d85149a05cb1f6dc49f0ba7a2ceca53718ae17/compiler-rt/test/builtins/Unit/subtf3_test.c
 
 const std = @import("std");
+const builtin = @import("builtin");
 const math = std.math;
 const qnan128: f128 = @bitCast(@as(u128, 0x7fff800000000000) << 64);
 
@@ -34,6 +35,8 @@ fn test__addtf3(a: f128, b: f128, expected_hi: u64, expected_lo: u64) !void {
 }
 
 test "addtf3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__addtf3(qnan128, 0x1.23456789abcdefp+5, 0x7fff800000000000, 0x0);
 
     // NaN + any = NaN
@@ -73,6 +76,9 @@ fn test__subtf3(a: f128, b: f128, expected_hi: u64, expected_lo: u64) !void {
 }
 
 test "subtf3" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     // qNaN - any = qNaN
     try test__subtf3(qnan128, 0x1.23456789abcdefp+5, 0x7fff800000000000, 0x0);
 
@@ -103,6 +109,8 @@ fn test__addxf3(a: f80, b: f80, expected: u80) !void {
 }
 
 test "addxf3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // NaN + any = NaN
     try test__addxf3(qnan80, 0x1.23456789abcdefp+5, @as(u80, @bitCast(qnan80)));
     try test__addxf3(@as(f80, @bitCast(@as(u80, 0x7fff_8000_8000_3000_0000))), 0x1.23456789abcdefp+5, @as(u80, @bitCast(qnan80)));

lib/compiler_rt/addoti4_test.zig

@@ -23,6 +23,8 @@ fn simple_addoti4(a: i128, b: i128, overflow: *c_int) i128 {
 }
 
 test "addoti4" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const min: i128 = math.minInt(i128);
     const max: i128 = math.maxInt(i128);
     var i: i128 = 1;

lib/compiler_rt/comparef.zig

@@ -98,6 +98,8 @@ pub inline fn cmp_f80(comptime RT: type, a: f80, b: f80) RT {
 }
 
 test "cmp_f80" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for (.{ LE, GE }) |RT| {
         try std.testing.expect(cmp_f80(RT, 1.0, 1.0) == RT.Equal);
         try std.testing.expect(cmp_f80(RT, 0.0, -0.0) == RT.Equal);

lib/compiler_rt/cos.zig

@@ -1,6 +1,4 @@
 const std = @import("std");
-const builtin = @import("builtin");
-const arch = builtin.cpu.arch;
 const math = std.math;
 const expect = std.testing.expect;
 const common = @import("common.zig");
@@ -136,6 +134,8 @@ pub fn cosl(x: c_longdouble) callconv(.C) c_longdouble {
 }
 
 test "cos32" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const epsilon = 0.00001;
 
     try expect(math.approxEqAbs(f32, cosf(0.0), 1.0, epsilon));

lib/compiler_rt/divtf3_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const math = std.math;
 const testing = std.testing;
 
@@ -30,6 +31,9 @@ fn test__divtf3(a: f128, b: f128, expectedHi: u64, expectedLo: u64) !void {
 }
 
 test "divtf3" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     // NaN / any = NaN
     try test__divtf3(math.nan(f128), 0x1.23456789abcdefp+5, 0x7fff800000000000, 0);
     // inf / any(except inf and nan) = inf

lib/compiler_rt/divxf3_test.zig

@@ -39,6 +39,8 @@ fn test__divxf3(a: f80, b: f80) !void {
 }
 
 test "divxf3" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // NaN / any = NaN
     try expect__divxf3_result(math.nan(f80), 0x1.23456789abcdefp+5, 0x7fffC000000000000000);
     // inf / any(except inf and nan) = inf

lib/compiler_rt/float_from_int_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const testing = std.testing;
 const math = std.math;
 
@@ -125,6 +126,9 @@ fn test__floatuntisf(a: u128, expected: f32) !void {
 }
 
 test "floattisf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floattisf(0, 0.0);
 
     try test__floattisf(1, 1.0);
@@ -171,6 +175,9 @@ test "floattisf" {
 }
 
 test "floatuntisf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floatuntisf(0, 0.0);
 
     try test__floatuntisf(1, 1.0);
@@ -367,6 +374,9 @@ fn test__floatuntidf(a: u128, expected: f64) !void {
 }
 
 test "floattidf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floattidf(0, 0.0);
 
     try test__floattidf(1, 1.0);
@@ -437,6 +447,9 @@ test "floattidf" {
 }
 
 test "floatuntidf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floatuntidf(0, 0.0);
 
     try test__floatuntidf(1, 1.0);
@@ -582,6 +595,9 @@ test "floatditf" {
 }
 
 test "floatunditf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floatunditf(0xffffffffffffffff, 0x403effffffffffff, 0xfffe000000000000);
     try test__floatunditf(0xfffffffffffffffe, 0x403effffffffffff, 0xfffc000000000000);
     try test__floatunditf(0x8000000000000000, 0x403e000000000000, 0x0);
@@ -603,6 +619,9 @@ fn test__floatuntitf(a: u128, expected: f128) !void {
 }
 
 test "floattitf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floattitf(0, 0.0);
 
     try test__floattitf(1, 1.0);
@@ -685,6 +704,9 @@ test "floattitf" {
 }
 
 test "floatuntitf" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test__floatuntitf(0, 0.0);
 
     try test__floatuntitf(1, 1.0);

lib/compiler_rt/fma.zig

@@ -343,6 +343,9 @@ test "64" {
 }
 
 test "128" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     const epsilon = 0.000001;
 
     try expect(math.approxEqAbs(f128, fmaq(0.0, 5.0, 9.124), 9.124, epsilon));

lib/compiler_rt/fmodx_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const fmod = @import("fmod.zig");
 const testing = std.testing;
 
@@ -22,6 +23,9 @@ fn test_fmodx_infs() !void {
 }
 
 test "fmodx" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     try test_fmodx(6.4, 4.0, 2.4);
     try test_fmodx(6.4, -4.0, 2.4);
     try test_fmodx(-6.4, 4.0, -2.4);

lib/compiler_rt/int.zig

@@ -42,6 +42,8 @@ pub fn __divmodti4(a: i128, b: i128, rem: *i128) callconv(.C) i128 {
 }
 
 test "test_divmodti4" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const cases = [_][4]i128{
         [_]i128{ 0, 1, 0, 0 },
         [_]i128{ 0, -1, 0, 0 },

lib/compiler_rt/int_from_float_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const testing = std.testing;
 const math = std.math;
 
@@ -40,6 +41,8 @@ fn test__fixunssfsi(a: f32, expected: u32) !void {
 }
 
 test "fixsfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixsfsi(-math.floatMax(f32), math.minInt(i32));
 
     try test__fixsfsi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i32));
@@ -103,6 +106,8 @@ test "fixsfsi" {
 }
 
 test "fixunssfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunssfsi(0.0, 0);
 
     try test__fixunssfsi(0.5, 0);
@@ -142,6 +147,8 @@ fn test__fixunssfdi(a: f32, expected: u64) !void {
 }
 
 test "fixsfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixsfdi(-math.floatMax(f32), math.minInt(i64));
 
     try test__fixsfdi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i64));
@@ -197,6 +204,8 @@ test "fixsfdi" {
 }
 
 test "fixunssfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunssfdi(0.0, 0);
 
     try test__fixunssfdi(0.5, 0);
@@ -235,6 +244,8 @@ fn test__fixunssfti(a: f32, expected: u128) !void {
 }
 
 test "fixsfti" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixsfti(-math.floatMax(f32), math.minInt(i128));
 
     try test__fixsfti(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i128));
@@ -306,6 +317,8 @@ test "fixsfti" {
 }
 
 test "fixunssfti" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunssfti(0.0, 0);
 
     try test__fixunssfti(0.5, 0);
@@ -352,6 +365,8 @@ fn test__fixunsdfsi(a: f64, expected: u32) !void {
 }
 
 test "fixdfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixdfsi(-math.floatMax(f64), math.minInt(i32));
 
     try test__fixdfsi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i32));
@@ -413,6 +428,8 @@ test "fixdfsi" {
 }
 
 test "fixunsdfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunsdfsi(0.0, 0);
 
     try test__fixunsdfsi(0.5, 0);
@@ -455,6 +472,8 @@ fn test__fixunsdfdi(a: f64, expected: u64) !void {
 }
 
 test "fixdfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixdfdi(-math.floatMax(f64), math.minInt(i64));
 
     try test__fixdfdi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i64));
@@ -508,6 +527,8 @@ test "fixdfdi" {
 }
 
 test "fixunsdfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunsdfdi(0.0, 0);
     try test__fixunsdfdi(0.5, 0);
     try test__fixunsdfdi(0.99, 0);
@@ -550,6 +571,8 @@ fn test__fixunsdfti(a: f64, expected: u128) !void {
 }
 
 test "fixdfti" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixdfti(-math.floatMax(f64), math.minInt(i128));
 
     try test__fixdfti(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i128));
@@ -603,6 +626,8 @@ test "fixdfti" {
 }
 
 test "fixunsdfti" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunsdfti(0.0, 0);
 
     try test__fixunsdfti(0.5, 0);
@@ -652,6 +677,8 @@ fn test__fixunstfsi(a: f128, expected: u32) !void {
 }
 
 test "fixtfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixtfsi(-math.floatMax(f128), math.minInt(i32));
 
     try test__fixtfsi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i32));
@@ -715,6 +742,8 @@ test "fixtfsi" {
 }
 
 test "fixunstfsi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunstfsi(math.inf(f128), 0xffffffff);
     try test__fixunstfsi(0, 0x0);
     try test__fixunstfsi(0x1.23456789abcdefp+5, 0x24);
@@ -738,6 +767,8 @@ fn test__fixunstfdi(a: f128, expected: u64) !void {
 }
 
 test "fixtfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixtfdi(-math.floatMax(f128), math.minInt(i64));
 
     try test__fixtfdi(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i64));
@@ -801,6 +832,8 @@ test "fixtfdi" {
 }
 
 test "fixunstfdi" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunstfdi(0.0, 0);
 
     try test__fixunstfdi(0.5, 0);
@@ -853,6 +886,8 @@ fn test__fixunstfti(a: f128, expected: u128) !void {
 }
 
 test "fixtfti" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixtfti(-math.floatMax(f128), math.minInt(i128));
 
     try test__fixtfti(-0x1.FFFFFFFFFFFFFp+1023, math.minInt(i128));
@@ -934,6 +969,8 @@ fn test__fixunshfti(a: f16, expected: u128) !void {
 }
 
 test "fixunshfti for f16" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try test__fixunshfti(math.inf(f16), math.maxInt(u128));
     try test__fixunshfti(math.floatMax(f16), 65504);
 }

lib/compiler_rt/mulf3_test.zig

@@ -3,6 +3,7 @@
 // https://github.com/llvm/llvm-project/blob/2ffb1b0413efa9a24eb3c49e710e36f92e2cb50b/compiler-rt/test/builtins/Unit/multf3_test.c
 
 const std = @import("std");
+const builtin = @import("builtin");
 const math = std.math;
 const qnan128: f128 = @bitCast(@as(u128, 0x7fff800000000000) << 64);
 const inf128: f128 = @bitCast(@as(u128, 0x7fff000000000000) << 64);
@@ -48,6 +49,9 @@ fn makeNaN128(rand: u64) f128 {
     return @bitCast(int_result);
 }
 test "multf3" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .bmi, .lzcnt })) return error.SkipZigTest;
+
     // qNaN * any = qNaN
     try test__multf3(qnan128, 0x1.23456789abcdefp+5, 0x7fff800000000000, 0x0);
 

lib/compiler_rt/negti2_test.zig

@@ -6,7 +6,9 @@ fn test__negti2(a: i128, expected: i128) !void {
     try testing.expectEqual(expected, result);
 }
 
-test "negdi2" {
+test "negti2" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // TODO ensuring that math.minInt(i128); returns error
 
     try test__negti2(-3, 3);

lib/compiler_rt/powiXf2_test.zig

@@ -3,8 +3,10 @@
 // powihf2 adapted from powisf2 tests
 
 const powiXf2 = @import("powiXf2.zig");
-const testing = @import("std").testing;
-const math = @import("std").math;
+const std = @import("std");
+const builtin = @import("builtin");
+const testing = std.testing;
+const math = std.math;
 
 fn test__powihf2(a: f16, b: i32, expected: f16) !void {
     var result = powiXf2.__powihf2(a, b);
@@ -32,6 +34,9 @@ fn test__powixf2(a: f80, b: i32, expected: f80) !void {
 }
 
 test "powihf2" {
+    if (builtin.zig_backend == .stage2_x86_64 and
+        !comptime std.Target.x86.featureSetHas(builtin.cpu.features, .f16c)) return error.SkipZigTest;
+
     const inf_f16 = math.inf(f16);
     try test__powisf2(0, 0, 1);
     try test__powihf2(1, 0, 1);
@@ -351,6 +356,8 @@ test "powidf2" {
 }
 
 test "powitf2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const inf_f128 = math.inf(f128);
     try test__powitf2(0, 0, 1);
     try test__powitf2(1, 0, 1);
@@ -456,6 +463,8 @@ test "powitf2" {
 }
 
 test "powixf2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const inf_f80 = math.inf(f80);
     try test__powixf2(0, 0, 1);
     try test__powixf2(1, 0, 1);

lib/compiler_rt/sin.zig

@@ -140,6 +140,8 @@ pub fn sinl(x: c_longdouble) callconv(.C) c_longdouble {
 }
 
 test "sin32" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const epsilon = 0.00001;
 
     try expect(math.approxEqAbs(f32, sinf(0.0), 0.0, epsilon));

lib/compiler_rt/suboti4_test.zig

@@ -27,6 +27,8 @@ pub fn simple_suboti4(a: i128, b: i128, overflow: *c_int) i128 {
 }
 
 test "suboti3" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const min: i128 = math.minInt(i128);
     const max: i128 = math.maxInt(i128);
     var i: i128 = 1;

lib/compiler_rt/tan.zig

@@ -131,6 +131,8 @@ test "tan" {
 }
 
 test "tan32" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const epsilon = 0.00001;
 
     try expect(math.approxEqAbs(f32, tanf(0.0), 0.0, epsilon));
@@ -142,6 +144,8 @@ test "tan32" {
 }
 
 test "tan64" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const epsilon = 0.000001;
 
     try expect(math.approxEqAbs(f64, tan(0.0), 0.0, epsilon));

lib/compiler_rt/udivmodei4.zig

@@ -129,7 +129,10 @@ pub fn __umodei4(r_p: [*]u32, u_p: [*]const u32, v_p: [*]const u32, bits: usize)
 }
 
 test "__udivei4/__umodei4" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const RndGen = std.rand.DefaultPrng;
     var rnd = RndGen.init(42);

lib/std/Build/Cache.zig

@@ -1007,6 +1007,8 @@ test "cache file and then recall it" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1072,6 +1074,9 @@ test "check that changing a file makes cache fail" {
         // https://github.com/ziglang/zig/issues/5437
         return error.SkipZigTest;
     }
+
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1146,6 +1151,8 @@ test "no file inputs" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1193,6 +1200,9 @@ test "Manifest with files added after initial hash work" {
         // https://github.com/ziglang/zig/issues/5437
         return error.SkipZigTest;
     }
+
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
 

lib/std/Build/Step/Options.zig

@@ -296,6 +296,8 @@ const Arg = struct {
 test Options {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena.deinit();
 

lib/std/Thread/Condition.zig

@@ -369,6 +369,8 @@ test "Condition - signal" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const num_threads = 4;
 
     const SignalTest = struct {
@@ -498,6 +500,8 @@ test "Condition - broadcasting" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const num_threads = 10;
 
     const BroadcastTest = struct {
@@ -565,6 +569,8 @@ test "Condition - broadcasting - wake all threads" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var num_runs: usize = 1;
     const num_threads = 10;
 

lib/std/Thread/Mutex.zig

@@ -289,6 +289,8 @@ test "Mutex - many contended" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const num_threads = 4;
     const num_increments = 1000;
 

lib/std/Thread/RwLock.zig

@@ -297,6 +297,8 @@ test "RwLock - concurrent access" {
     if (builtin.single_threaded)
         return;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const num_writers: usize = 2;
     const num_readers: usize = 4;
     const num_writes: usize = 10000;

lib/std/Uri.zig

@@ -685,6 +685,8 @@ test "Special test" {
 }
 
 test "URI escaping" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const input = "\\ö/ äöß ~~.adas-https://canvas:123/#ads&&sad";
     const expected = "%5C%C3%B6%2F%20%C3%A4%C3%B6%C3%9F%20~~.adas-https%3A%2F%2Fcanvas%3A123%2F%23ads%26%26sad";
 

lib/std/array_hash_map.zig

@@ -1,4 +1,5 @@
 const std = @import("std.zig");
+const builtin = @import("builtin");
 const debug = std.debug;
 const assert = debug.assert;
 const testing = std.testing;
@@ -2137,6 +2138,8 @@ test "ensure capacity leak" {
 }
 
 test "big map" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer map.deinit();
 
@@ -2190,6 +2193,8 @@ test "big map" {
 }
 
 test "clone" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var original = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer original.deinit();
 
@@ -2216,6 +2221,8 @@ test "clone" {
 }
 
 test "shrink" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer map.deinit();
 
@@ -2256,6 +2263,8 @@ test "shrink" {
 }
 
 test "pop" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer map.deinit();
 
@@ -2274,6 +2283,8 @@ test "pop" {
 }
 
 test "popOrNull" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer map.deinit();
 
@@ -2294,6 +2305,8 @@ test "popOrNull" {
 }
 
 test "reIndex" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = ArrayHashMap(i32, i32, AutoContext(i32), true).init(std.testing.allocator);
     defer map.deinit();
 
@@ -2338,6 +2351,8 @@ test "auto store_hash" {
 }
 
 test "sort" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoArrayHashMap(i32, i32).init(std.testing.allocator);
     defer map.deinit();
 

lib/std/array_list.zig

@@ -1,4 +1,5 @@
 const std = @import("std.zig");
+const builtin = @import("builtin");
 const debug = std.debug;
 const assert = debug.assert;
 const testing = std.testing;
@@ -1183,6 +1184,8 @@ test "std.ArrayList/ArrayListUnmanaged.initCapacity" {
 }
 
 test "std.ArrayList/ArrayListUnmanaged.clone" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a = testing.allocator;
     {
         var array = ArrayList(i32).init(a);
@@ -1224,6 +1227,8 @@ test "std.ArrayList/ArrayListUnmanaged.clone" {
 }
 
 test "std.ArrayList/ArrayListUnmanaged.basic" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a = testing.allocator;
     {
         var list = ArrayList(i32).init(a);
@@ -1508,6 +1513,8 @@ test "std.ArrayList/ArrayListUnmanaged.insert" {
 }
 
 test "std.ArrayList/ArrayListUnmanaged.insertSlice" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a = testing.allocator;
     {
         var list = ArrayList(i32).init(a);
@@ -1554,6 +1561,8 @@ test "std.ArrayList/ArrayListUnmanaged.insertSlice" {
 }
 
 test "std.ArrayList/ArrayListUnmanaged.replaceRange" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena = std.heap.ArenaAllocator.init(testing.allocator);
     defer arena.deinit();
     const a = arena.allocator();
@@ -1725,6 +1734,8 @@ test "shrink still sets length when resizing is disabled" {
 }
 
 test "shrinkAndFree with a copy" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var failing_allocator = testing.FailingAllocator.init(testing.allocator, .{ .resize_fail_index = 0 });
     const a = failing_allocator.allocator();
 

lib/std/atomic/Atomic.zig

@@ -374,6 +374,8 @@ const atomic_rmw_orderings = [_]Ordering{
 };
 
 test "Atomic.swap" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for (atomic_rmw_orderings) |ordering| {
         var x = Atomic(usize).init(5);
         try testing.expectEqual(x.swap(10, ordering), 5);
@@ -467,6 +469,8 @@ test "Atomic.fetchSub" {
 }
 
 test "Atomic.fetchMin" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for (atomicIntTypes()) |Int| {
         inline for (atomic_rmw_orderings) |ordering| {
             var x = Atomic(Int).init(5);

lib/std/atomic/queue.zig

@@ -175,6 +175,8 @@ const puts_per_thread = 500;
 const put_thread_count = 3;
 
 test "std.atomic.Queue" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var plenty_of_memory = try std.heap.page_allocator.alloc(u8, 300 * 1024);
     defer std.heap.page_allocator.free(plenty_of_memory);
 

lib/std/base64.zig

@@ -1,5 +1,6 @@
 const std = @import("std.zig");
 const assert = std.debug.assert;
+const builtin = @import("builtin");
 const testing = std.testing;
 const mem = std.mem;
 
@@ -354,12 +355,16 @@ pub const Base64DecoderWithIgnore = struct {
 };
 
 test "base64" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     @setEvalBranchQuota(8000);
     try testBase64();
     try comptime testAllApis(standard, "comptime", "Y29tcHRpbWU=");
 }
 
 test "base64 padding dest overflow" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const input = "foo";
 
     var expect: [128]u8 = undefined;
@@ -374,6 +379,8 @@ test "base64 padding dest overflow" {
 }
 
 test "base64 url_safe_no_pad" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     @setEvalBranchQuota(8000);
     try testBase64UrlSafeNoPad();
     try comptime testAllApis(url_safe_no_pad, "comptime", "Y29tcHRpbWU");

lib/std/bit_set.zig

@@ -33,6 +33,7 @@
 const std = @import("std.zig");
 const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
+const builtin = @import("builtin");
 
 /// Returns the optimal static bit set type for the specified number
 /// of elements: either `IntegerBitSet` or `ArrayBitSet`,
@@ -1636,7 +1637,10 @@ fn testStaticBitSet(comptime Set: type) !void {
 }
 
 test "IntegerBitSet" {
-    if (@import("builtin").zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     try testStaticBitSet(IntegerBitSet(0));
     try testStaticBitSet(IntegerBitSet(1));
@@ -1649,6 +1653,11 @@ test "IntegerBitSet" {
 }
 
 test "ArrayBitSet" {
+    switch (builtin.zig_backend) {
+        .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
+
     inline for (.{ 0, 1, 2, 31, 32, 33, 63, 64, 65, 254, 500, 3000 }) |size| {
         try testStaticBitSet(ArrayBitSet(u8, size));
         try testStaticBitSet(ArrayBitSet(u16, size));
@@ -1659,6 +1668,8 @@ test "ArrayBitSet" {
 }
 
 test "DynamicBitSetUnmanaged" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     var a = try DynamicBitSetUnmanaged.initEmpty(allocator, 300);
     try testing.expectEqual(@as(usize, 0), a.count());
@@ -1712,6 +1723,8 @@ test "DynamicBitSetUnmanaged" {
 }
 
 test "DynamicBitSet" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     var a = try DynamicBitSet.initEmpty(allocator, 300);
     try testing.expectEqual(@as(usize, 0), a.count());

lib/std/compress/deflate/compressor.zig

@@ -1069,6 +1069,8 @@ var deflate_tests = [_]DeflateTest{
 };
 
 test "deflate" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     for (deflate_tests) |dt| {
         var output = ArrayList(u8).init(testing.allocator);
         defer output.deinit();

lib/std/compress/deflate/compressor_test.zig

@@ -154,6 +154,8 @@ fn testToFromWithLimit(input: []const u8, limit: [11]u32) !void {
 }
 
 test "deflate/inflate" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var limits = [_]u32{0} ** 11;
 
     var test0 = [_]u8{};
@@ -178,6 +180,8 @@ test "deflate/inflate" {
 }
 
 test "very long sparse chunk" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // A SparseReader returns a stream consisting of 0s ending with 65,536 (1<<16) 1s.
     // This tests missing hash references in a very large input.
     const SparseReader = struct {
@@ -239,6 +243,8 @@ test "very long sparse chunk" {
 }
 
 test "compressor reset" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     for (std.enums.values(deflate.Compression)) |c| {
         try testWriterReset(c, null);
         try testWriterReset(c, "dict");
@@ -289,6 +295,8 @@ fn testWriterReset(level: deflate.Compression, dict: ?[]const u8) !void {
 }
 
 test "decompressor dictionary" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const dict = "hello world"; // dictionary
     const text = "hello again world";
 
@@ -329,6 +337,8 @@ test "decompressor dictionary" {
 }
 
 test "compressor dictionary" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const dict = "hello world";
     const text = "hello again world";
 
@@ -375,6 +385,8 @@ test "compressor dictionary" {
 // Update the hash for best_speed only if d.index < d.maxInsertIndex
 // See https://golang.org/issue/2508
 test "Go non-regression test for 2508" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var comp = try compressor(
         testing.allocator,
         io.null_writer,
@@ -392,6 +404,8 @@ test "Go non-regression test for 2508" {
 }
 
 test "deflate/inflate string" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const StringTest = struct {
         filename: []const u8,
         limit: [11]u32,
@@ -439,6 +453,8 @@ test "deflate/inflate string" {
 }
 
 test "inflate reset" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const strings = [_][]const u8{
         "lorem ipsum izzle fo rizzle",
         "the quick brown fox jumped over",
@@ -485,6 +501,8 @@ test "inflate reset" {
 }
 
 test "inflate reset dictionary" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const dict = "the lorem fox";
     const strings = [_][]const u8{
         "lorem ipsum izzle fo rizzle",

lib/std/compress/deflate/deflate_fast.zig

@@ -649,6 +649,8 @@ test "best speed shift offsets" {
 }
 
 test "best speed reset" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // test that encoding is consistent across a warparound of the table offset.
     // See https://github.com/golang/go/issues/34121
     const fmt = std.fmt;

lib/std/compress/deflate/deflate_fast_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const expect = std.testing.expect;
 const io = std.io;
 const mem = std.mem;
@@ -11,6 +12,8 @@ const inflate = @import("decompressor.zig");
 const deflate_const = @import("deflate_const.zig");
 
 test "best speed" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Tests that round-tripping through deflate and then inflate recovers the original input.
     // The Write sizes are near the thresholds in the compressor.encSpeed method (0, 16, 128), as well
     // as near `deflate_const.max_store_block_size` (65535).
@@ -93,6 +96,8 @@ test "best speed" {
 }
 
 test "best speed max match offset" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const abc = "abcdefgh";
     const xyz = "stuvwxyz";
     const input_margin = 16 - 1;

lib/std/compress/deflate/huffman_bit_writer.zig

@@ -845,6 +845,8 @@ const testing = std.testing;
 const ArrayList = std.ArrayList;
 
 test "writeBlockHuff" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Tests huffman encoding against reference files to detect possible regressions.
     // If encoding/bit allocation changes you can regenerate these files
 
@@ -1569,6 +1571,8 @@ const TestType = enum {
 };
 
 test "writeBlock" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // tests if the writeBlock encoding has changed.
 
     const ttype: TestType = .write_block;
@@ -1584,6 +1588,8 @@ test "writeBlock" {
 }
 
 test "writeBlockDynamic" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // tests if the writeBlockDynamic encoding has changed.
 
     const ttype: TestType = .write_dyn_block;

lib/std/compress/deflate/huffman_code.zig

@@ -360,6 +360,8 @@ fn byFreq(context: void, a: LiteralNode, b: LiteralNode) bool {
 }
 
 test "generate a Huffman code from an array of frequencies" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var freqs: [19]u16 = [_]u16{
         8, // 0
         1, // 1

lib/std/compress/gzip.zig

@@ -174,6 +174,8 @@ fn testReader(data: []const u8, comptime expected: []const u8) !void {
 // https://tools.ietf.org/rfc/rfc1952.txt length=25037 bytes
 // SHA256=164ef0897b4cbec63abf1b57f069f3599bd0fb7c72c2a4dee21bd7e03ec9af67
 test "compressed data" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testReader(
         @embedFile("testdata/rfc1952.txt.gz"),
         @embedFile("testdata/rfc1952.txt"),

lib/std/compress/lzma/test.zig

@@ -1,4 +1,5 @@
 const std = @import("../../std.zig");
+const builtin = @import("builtin");
 const lzma = @import("../lzma.zig");
 
 fn testDecompress(compressed: []const u8) ![]u8 {
@@ -22,6 +23,8 @@ fn testDecompressError(expected: anyerror, compressed: []const u8) !void {
 }
 
 test "LZMA: decompress empty world" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "",
         &[_]u8{
@@ -32,6 +35,8 @@ test "LZMA: decompress empty world" {
 }
 
 test "LZMA: decompress hello world" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "Hello world\n",
         &[_]u8{
@@ -43,6 +48,8 @@ test "LZMA: decompress hello world" {
 }
 
 test "LZMA: decompress huge dict" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "Hello world\n",
         &[_]u8{
@@ -54,6 +61,8 @@ test "LZMA: decompress huge dict" {
 }
 
 test "LZMA: unknown size with end of payload marker" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "Hello\nWorld!\n",
         @embedFile("testdata/good-unknown_size-with_eopm.lzma"),
@@ -61,6 +70,8 @@ test "LZMA: unknown size with end of payload marker" {
 }
 
 test "LZMA: known size without end of payload marker" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "Hello\nWorld!\n",
         @embedFile("testdata/good-known_size-without_eopm.lzma"),
@@ -68,6 +79,8 @@ test "LZMA: known size without end of payload marker" {
 }
 
 test "LZMA: known size with end of payload marker" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressEqual(
         "Hello\nWorld!\n",
         @embedFile("testdata/good-known_size-with_eopm.lzma"),
@@ -75,6 +88,8 @@ test "LZMA: known size with end of payload marker" {
 }
 
 test "LZMA: too big uncompressed size in header" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressError(
         error.CorruptInput,
         @embedFile("testdata/bad-too_big_size-with_eopm.lzma"),
@@ -82,6 +97,8 @@ test "LZMA: too big uncompressed size in header" {
 }
 
 test "LZMA: too small uncompressed size in header" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testDecompressError(
         error.CorruptInput,
         @embedFile("testdata/bad-too_small_size-without_eopm-3.lzma"),

lib/std/compress/lzma/vec2d.zig

@@ -50,6 +50,8 @@ const expectEqualSlices = std.testing.expectEqualSlices;
 const expectError = std.testing.expectError;
 
 test "Vec2D.init" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = testing.allocator;
     var vec2d = try Vec2D(i32).init(allocator, 1, .{ 2, 3 });
     defer vec2d.deinit(allocator);

lib/std/compress/xz/test.zig

@@ -19,6 +19,8 @@ fn testReader(data: []const u8, comptime expected: []const u8) !void {
 }
 
 test "compressed data" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testReader(@embedFile("testdata/good-0-empty.xz"), "");
 
     inline for ([_][]const u8{

lib/std/compress/zlib.zig

@@ -199,6 +199,8 @@ fn testDecompress(data: []const u8, expected: []const u8) !void {
 // https://tools.ietf.org/rfc/rfc1951.txt length=36944 bytes
 // SHA256=5ebf4b5b7fe1c3a0c0ab9aa3ac8c0f3853a7dc484905e76e03b0b0f301350009
 test "compressed data" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const rfc1951_txt = @embedFile("testdata/rfc1951.txt");
 
     // Compressed with compression level = 0
@@ -264,6 +266,8 @@ test "sanity checks" {
 }
 
 test "compress data" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = testing.allocator;
     const rfc1951_txt = @embedFile("testdata/rfc1951.txt");
 

lib/std/compress/zstandard.zig

@@ -264,6 +264,8 @@ fn testReader(data: []const u8, comptime expected: []const u8) !void {
 }
 
 test "zstandard decompression" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const uncompressed = @embedFile("testdata/rfc8478.txt");
     const compressed3 = @embedFile("testdata/rfc8478.txt.zst.3");
     const compressed19 = @embedFile("testdata/rfc8478.txt.zst.19");

lib/std/crypto.zig

@@ -314,6 +314,8 @@ test "CSPRNG" {
 }
 
 test "issue #4532: no index out of bounds" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const types = [_]type{
         hash.Md5,
         hash.Sha1,

lib/std/crypto/25519/curve25519.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 
 const IdentityElementError = crypto.errors.IdentityElementError;
@@ -111,6 +112,8 @@ pub const Curve25519 = struct {
 };
 
 test "curve25519" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var s = [32]u8{ 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8 };
     const p = try Curve25519.basePoint.clampedMul(s);
     try p.rejectIdentity();
@@ -125,6 +128,8 @@ test "curve25519" {
 }
 
 test "curve25519 small order check" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var s: [32]u8 = [_]u8{1} ++ [_]u8{0} ** 31;
     const small_order_ss: [7][32]u8 = .{
         .{

lib/std/crypto/25519/ed25519.zig

@@ -1,5 +1,5 @@
-const builtin = @import("builtin");
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const debug = std.debug;
 const fmt = std.fmt;
@@ -484,6 +484,8 @@ pub const Ed25519 = struct {
 };
 
 test "ed25519 key pair creation" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [32]u8 = undefined;
     _ = try fmt.hexToBytes(seed[0..], "8052030376d47112be7f73ed7a019293dd12ad910b654455798b4667d73de166");
     const key_pair = try Ed25519.KeyPair.create(seed);
@@ -493,6 +495,8 @@ test "ed25519 key pair creation" {
 }
 
 test "ed25519 signature" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [32]u8 = undefined;
     _ = try fmt.hexToBytes(seed[0..], "8052030376d47112be7f73ed7a019293dd12ad910b654455798b4667d73de166");
     const key_pair = try Ed25519.KeyPair.create(seed);
@@ -505,6 +509,8 @@ test "ed25519 signature" {
 }
 
 test "ed25519 batch verification" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var i: usize = 0;
     while (i < 100) : (i += 1) {
         const key_pair = try Ed25519.KeyPair.create(null);
@@ -534,6 +540,8 @@ test "ed25519 batch verification" {
 }
 
 test "ed25519 test vectors" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Vec = struct {
         msg_hex: *const [64:0]u8,
         public_key_hex: *const [64:0]u8,
@@ -636,6 +644,8 @@ test "ed25519 test vectors" {
 }
 
 test "ed25519 with blind keys" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const BlindKeyPair = Ed25519.key_blinding.BlindKeyPair;
 
     // Create a standard Ed25519 key pair
@@ -659,6 +669,8 @@ test "ed25519 with blind keys" {
 }
 
 test "ed25519 signatures with streaming" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const kp = try Ed25519.KeyPair.create(null);
 
     var signer = try kp.signer(null);
@@ -675,6 +687,8 @@ test "ed25519 signatures with streaming" {
 }
 
 test "ed25519 key pair from secret key" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const kp = try Ed25519.KeyPair.create(null);
     const kp2 = try Ed25519.KeyPair.fromSecretKey(kp.secret_key);
     try std.testing.expectEqualSlices(u8, &kp.secret_key.toBytes(), &kp2.secret_key.toBytes());

lib/std/crypto/25519/edwards25519.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const debug = std.debug;
 const fmt = std.fmt;
@@ -494,6 +495,8 @@ pub const Edwards25519 = struct {
 const htest = @import("../test.zig");
 
 test "edwards25519 packing/unpacking" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s = [_]u8{170} ++ [_]u8{0} ** 31;
     var b = Edwards25519.basePoint;
     const pk = try b.mul(s);
@@ -530,6 +533,8 @@ test "edwards25519 packing/unpacking" {
 }
 
 test "edwards25519 point addition/subtraction" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var s1: [32]u8 = undefined;
     var s2: [32]u8 = undefined;
     crypto.random.bytes(&s1);
@@ -544,6 +549,8 @@ test "edwards25519 point addition/subtraction" {
 }
 
 test "edwards25519 uniform-to-point" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var r = [32]u8{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 };
     var p = Edwards25519.fromUniform(r);
     try htest.assertEqual("0691eee3cf70a0056df6bfa03120635636581b5c4ea571dfc680f78c7e0b4137", p.toBytes()[0..]);
@@ -555,6 +562,8 @@ test "edwards25519 uniform-to-point" {
 
 // Test vectors from draft-irtf-cfrg-hash-to-curve-12
 test "edwards25519 hash-to-curve operation" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var p = Edwards25519.fromString(true, "QUUX-V01-CS02-with-edwards25519_XMD:SHA-512_ELL2_RO_", "abc");
     try htest.assertEqual("31558a26887f23fb8218f143e69d5f0af2e7831130bd5b432ef23883b895839a", p.toBytes()[0..]);
 
@@ -563,6 +572,8 @@ test "edwards25519 hash-to-curve operation" {
 }
 
 test "edwards25519 implicit reduction of invalid scalars" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s = [_]u8{0} ** 31 ++ [_]u8{255};
     const p1 = try Edwards25519.basePoint.mulPublic(s);
     const p2 = try Edwards25519.basePoint.mul(s);

lib/std/crypto/25519/ristretto255.zig

@@ -168,6 +168,8 @@ pub const Ristretto255 = struct {
 };
 
 test "ristretto255" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = Ristretto255.basePoint;
     var buf: [256]u8 = undefined;
     try std.testing.expectEqualStrings(try std.fmt.bufPrint(&buf, "{s}", .{std.fmt.fmtSliceHexUpper(&p.toBytes())}), "E2F2AE0A6ABC4E71A884A961C500515F58E30B6AA582DD8DB6A65945E08D2D76");

lib/std/crypto/25519/x25519.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const mem = std.mem;
 const fmt = std.fmt;
@@ -82,6 +83,8 @@ pub const X25519 = struct {
 const htest = @import("../test.zig");
 
 test "x25519 public key calculation from secret key" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var sk: [32]u8 = undefined;
     var pk_expected: [32]u8 = undefined;
     _ = try fmt.hexToBytes(sk[0..], "8052030376d47112be7f73ed7a019293dd12ad910b654455798b4667d73de166");
@@ -91,6 +94,8 @@ test "x25519 public key calculation from secret key" {
 }
 
 test "x25519 rfc7748 vector1" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const secret_key = [32]u8{ 0xa5, 0x46, 0xe3, 0x6b, 0xf0, 0x52, 0x7c, 0x9d, 0x3b, 0x16, 0x15, 0x4b, 0x82, 0x46, 0x5e, 0xdd, 0x62, 0x14, 0x4c, 0x0a, 0xc1, 0xfc, 0x5a, 0x18, 0x50, 0x6a, 0x22, 0x44, 0xba, 0x44, 0x9a, 0xc4 };
     const public_key = [32]u8{ 0xe6, 0xdb, 0x68, 0x67, 0x58, 0x30, 0x30, 0xdb, 0x35, 0x94, 0xc1, 0xa4, 0x24, 0xb1, 0x5f, 0x7c, 0x72, 0x66, 0x24, 0xec, 0x26, 0xb3, 0x35, 0x3b, 0x10, 0xa9, 0x03, 0xa6, 0xd0, 0xab, 0x1c, 0x4c };
 
@@ -101,6 +106,8 @@ test "x25519 rfc7748 vector1" {
 }
 
 test "x25519 rfc7748 vector2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const secret_key = [32]u8{ 0x4b, 0x66, 0xe9, 0xd4, 0xd1, 0xb4, 0x67, 0x3c, 0x5a, 0xd2, 0x26, 0x91, 0x95, 0x7d, 0x6a, 0xf5, 0xc1, 0x1b, 0x64, 0x21, 0xe0, 0xea, 0x01, 0xd4, 0x2c, 0xa4, 0x16, 0x9e, 0x79, 0x18, 0xba, 0x0d };
     const public_key = [32]u8{ 0xe5, 0x21, 0x0f, 0x12, 0x78, 0x68, 0x11, 0xd3, 0xf4, 0xb7, 0x95, 0x9d, 0x05, 0x38, 0xae, 0x2c, 0x31, 0xdb, 0xe7, 0x10, 0x6f, 0xc0, 0x3c, 0x3e, 0xfc, 0x4c, 0xd5, 0x49, 0xc7, 0x15, 0xa4, 0x93 };
 
@@ -111,6 +118,8 @@ test "x25519 rfc7748 vector2" {
 }
 
 test "x25519 rfc7748 one iteration" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const initial_value = [32]u8{ 0x09, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
     const expected_output = [32]u8{ 0x42, 0x2c, 0x8e, 0x7a, 0x62, 0x27, 0xd7, 0xbc, 0xa1, 0x35, 0x0b, 0x3e, 0x2b, 0xb7, 0x27, 0x9f, 0x78, 0x97, 0xb8, 0x7b, 0xb6, 0x85, 0x4b, 0x78, 0x3c, 0x60, 0xe8, 0x03, 0x11, 0xae, 0x30, 0x79 };
 
@@ -128,6 +137,8 @@ test "x25519 rfc7748 one iteration" {
 }
 
 test "x25519 rfc7748 1,000 iterations" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // These iteration tests are slow so we always skip them. Results have been verified.
     if (true) {
         return error.SkipZigTest;
@@ -150,6 +161,8 @@ test "x25519 rfc7748 1,000 iterations" {
 }
 
 test "x25519 rfc7748 1,000,000 iterations" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (true) {
         return error.SkipZigTest;
     }
@@ -171,6 +184,8 @@ test "x25519 rfc7748 1,000,000 iterations" {
 }
 
 test "edwards25519 -> curve25519 map" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const ed_kp = try crypto.sign.Ed25519.KeyPair.create([_]u8{0x42} ** 32);
     const mont_kp = try X25519.KeyPair.fromEd25519(ed_kp);
     try htest.assertEqual("90e7595fc89e52fdfddce9c6a43d74dbf6047025ee0462d2d172e8b6a2841d6e", &mont_kp.secret_key);

lib/std/crypto/Certificate.zig

@@ -624,6 +624,8 @@ pub fn parseTimeDigits(text: *const [2]u8, min: u8, max: u8) !u8 {
 }
 
 test parseTimeDigits {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expectEqual = std.testing.expectEqual;
     try expectEqual(@as(u8, 0), try parseTimeDigits("00", 0, 99));
     try expectEqual(@as(u8, 99), try parseTimeDigits("99", 0, 99));
@@ -645,6 +647,8 @@ pub fn parseYear4(text: *const [4]u8) !u16 {
 }
 
 test parseYear4 {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expectEqual = std.testing.expectEqual;
     try expectEqual(@as(u16, 0), try parseYear4("0000"));
     try expectEqual(@as(u16, 9999), try parseYear4("9999"));
@@ -1119,3 +1123,5 @@ pub const rsa = struct {
         return res;
     }
 };
+
+const builtin = @import("builtin");

lib/std/crypto/Certificate/Bundle.zig

@@ -318,6 +318,8 @@ const MapContext = struct {
 test "scan for OS-provided certificates" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var bundle: Bundle = .{};
     defer bundle.deinit(std.testing.allocator);
 

lib/std/crypto/aegis.zig

@@ -17,6 +17,7 @@
 //! https://datatracker.ietf.org/doc/draft-irtf-cfrg-aegis-aead/
 
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const mem = std.mem;
 const assert = std.debug.assert;
@@ -513,6 +514,8 @@ const htest = @import("test.zig");
 const testing = std.testing;
 
 test "Aegis128L test vector 1" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis128L.key_length]u8 = [_]u8{ 0x10, 0x01 } ++ [_]u8{0x00} ** 14;
     const nonce: [Aegis128L.nonce_length]u8 = [_]u8{ 0x10, 0x00, 0x02 } ++ [_]u8{0x00} ** 13;
     const ad = [8]u8{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 };
@@ -536,6 +539,8 @@ test "Aegis128L test vector 1" {
 }
 
 test "Aegis128L test vector 2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis128L.key_length]u8 = [_]u8{0x00} ** 16;
     const nonce: [Aegis128L.nonce_length]u8 = [_]u8{0x00} ** 16;
     const ad = [_]u8{};
@@ -553,6 +558,8 @@ test "Aegis128L test vector 2" {
 }
 
 test "Aegis128L test vector 3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis128L.key_length]u8 = [_]u8{0x00} ** 16;
     const nonce: [Aegis128L.nonce_length]u8 = [_]u8{0x00} ** 16;
     const ad = [_]u8{};
@@ -569,6 +576,8 @@ test "Aegis128L test vector 3" {
 }
 
 test "Aegis256 test vector 1" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis256.key_length]u8 = [_]u8{ 0x10, 0x01 } ++ [_]u8{0x00} ** 30;
     const nonce: [Aegis256.nonce_length]u8 = [_]u8{ 0x10, 0x00, 0x02 } ++ [_]u8{0x00} ** 29;
     const ad = [8]u8{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 };
@@ -592,6 +601,8 @@ test "Aegis256 test vector 1" {
 }
 
 test "Aegis256 test vector 2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis256.key_length]u8 = [_]u8{0x00} ** 32;
     const nonce: [Aegis256.nonce_length]u8 = [_]u8{0x00} ** 32;
     const ad = [_]u8{};
@@ -609,6 +620,8 @@ test "Aegis256 test vector 2" {
 }
 
 test "Aegis256 test vector 3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aegis256.key_length]u8 = [_]u8{0x00} ** 32;
     const nonce: [Aegis256.nonce_length]u8 = [_]u8{0x00} ** 32;
     const ad = [_]u8{};
@@ -625,6 +638,8 @@ test "Aegis256 test vector 3" {
 }
 
 test "Aegis MAC" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{0x00} ** Aegis128LMac.key_length;
     var msg: [64]u8 = undefined;
     for (&msg, 0..) |*m, i| {

lib/std/crypto/aes.zig

@@ -28,6 +28,8 @@ pub const Aes128 = impl.Aes128;
 pub const Aes256 = impl.Aes256;
 
 test "ctr" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // NIST SP 800-38A pp 55-58
     const ctr = @import("modes.zig").ctr;
 
@@ -53,6 +55,8 @@ test "ctr" {
 }
 
 test "encrypt" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Appendix B
     {
         const key = [_]u8{ 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c };
@@ -82,6 +86,8 @@ test "encrypt" {
 }
 
 test "decrypt" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Appendix B
     {
         const key = [_]u8{ 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c };
@@ -111,6 +117,8 @@ test "decrypt" {
 }
 
 test "expand 128-bit key" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{ 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c };
     const exp_enc = [_]*const [32:0]u8{
         "2b7e151628aed2a6abf7158809cf4f3c", "a0fafe1788542cb123a339392a6c7605", "f2c295f27a96b9435935807a7359f67f", "3d80477d4716fe3e1e237e446d7a883b", "ef44a541a8525b7fb671253bdb0bad00", "d4d1c6f87c839d87caf2b8bc11f915bc", "6d88a37a110b3efddbf98641ca0093fd", "4e54f70e5f5fc9f384a64fb24ea6dc4f", "ead27321b58dbad2312bf5607f8d292f", "ac7766f319fadc2128d12941575c006e", "d014f9a8c9ee2589e13f0cc8b6630ca6",
@@ -133,6 +141,8 @@ test "expand 128-bit key" {
 }
 
 test "expand 256-bit key" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{
         0x60, 0x3d, 0xeb, 0x10,
         0x15, 0xca, 0x71, 0xbe,

lib/std/crypto/aes_gcm.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const assert = std.debug.assert;
 const crypto = std.crypto;
 const debug = std.debug;
@@ -112,6 +113,8 @@ const htest = @import("test.zig");
 const testing = std.testing;
 
 test "Aes256Gcm - Empty message and no associated data" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aes256Gcm.key_length]u8 = [_]u8{0x69} ** Aes256Gcm.key_length;
     const nonce: [Aes256Gcm.nonce_length]u8 = [_]u8{0x42} ** Aes256Gcm.nonce_length;
     const ad = "";
@@ -124,6 +127,8 @@ test "Aes256Gcm - Empty message and no associated data" {
 }
 
 test "Aes256Gcm - Associated data only" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aes256Gcm.key_length]u8 = [_]u8{0x69} ** Aes256Gcm.key_length;
     const nonce: [Aes256Gcm.nonce_length]u8 = [_]u8{0x42} ** Aes256Gcm.nonce_length;
     const m = "";
@@ -136,6 +141,8 @@ test "Aes256Gcm - Associated data only" {
 }
 
 test "Aes256Gcm - Message only" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aes256Gcm.key_length]u8 = [_]u8{0x69} ** Aes256Gcm.key_length;
     const nonce: [Aes256Gcm.nonce_length]u8 = [_]u8{0x42} ** Aes256Gcm.nonce_length;
     const m = "Test with message only";
@@ -153,6 +160,8 @@ test "Aes256Gcm - Message only" {
 }
 
 test "Aes256Gcm - Message and associated data" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key: [Aes256Gcm.key_length]u8 = [_]u8{0x69} ** Aes256Gcm.key_length;
     const nonce: [Aes256Gcm.nonce_length]u8 = [_]u8{0x42} ** Aes256Gcm.nonce_length;
     const m = "Test with message";

lib/std/crypto/aes_ocb.zig

@@ -261,7 +261,10 @@ inline fn xorWith(x: *Block, y: Block) void {
 const hexToBytes = std.fmt.hexToBytes;
 
 test "AesOcb test vector 1" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     var k: [Aes128Ocb.key_length]u8 = undefined;
     var nonce: [Aes128Ocb.nonce_length]u8 = undefined;
@@ -280,7 +283,10 @@ test "AesOcb test vector 1" {
 }
 
 test "AesOcb test vector 2" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     var k: [Aes128Ocb.key_length]u8 = undefined;
     var nonce: [Aes128Ocb.nonce_length]u8 = undefined;
@@ -301,7 +307,10 @@ test "AesOcb test vector 2" {
 }
 
 test "AesOcb test vector 3" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     var k: [Aes128Ocb.key_length]u8 = undefined;
     var nonce: [Aes128Ocb.nonce_length]u8 = undefined;
@@ -325,7 +334,10 @@ test "AesOcb test vector 3" {
 }
 
 test "AesOcb test vector 4" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     var k: [Aes128Ocb.key_length]u8 = undefined;
     var nonce: [Aes128Ocb.nonce_length]u8 = undefined;

lib/std/crypto/argon2.zig

@@ -622,6 +622,8 @@ pub fn strVerify(
 }
 
 test "argon2d" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const password = [_]u8{0x01} ** 32;
     const salt = [_]u8{0x02} ** 16;
     const secret = [_]u8{0x03} ** 8;
@@ -647,6 +649,8 @@ test "argon2d" {
 }
 
 test "argon2i" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const password = [_]u8{0x01} ** 32;
     const salt = [_]u8{0x02} ** 16;
     const secret = [_]u8{0x03} ** 8;
@@ -672,6 +676,8 @@ test "argon2i" {
 }
 
 test "argon2id" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const password = [_]u8{0x01} ** 32;
     const salt = [_]u8{0x02} ** 16;
     const secret = [_]u8{0x03} ** 8;
@@ -697,6 +703,8 @@ test "argon2id" {
 }
 
 test "kdf" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const password = "password";
     const salt = "somesalt";
 
@@ -896,6 +904,8 @@ test "kdf" {
 }
 
 test "phc format hasher" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     const password = "testpass";
 
@@ -911,6 +921,8 @@ test "phc format hasher" {
 }
 
 test "password hash and password verify" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     const password = "testpass";
 
@@ -924,6 +936,8 @@ test "password hash and password verify" {
 }
 
 test "kdf derived key length" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
 
     const password = "testpass";

lib/std/crypto/bcrypt.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const base64 = std.base64;
 const crypto = std.crypto;
 const debug = std.debug;
@@ -753,6 +754,8 @@ pub fn strVerify(
 }
 
 test "bcrypt codec" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var salt: [salt_length]u8 = undefined;
     crypto.random.bytes(&salt);
     var salt_str: [salt_str_length]u8 = undefined;
@@ -763,6 +766,8 @@ test "bcrypt codec" {
 }
 
 test "bcrypt crypt format" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var hash_options = HashOptions{
         .params = .{ .rounds_log = 5 },
         .encoding = .crypt,
@@ -803,6 +808,8 @@ test "bcrypt crypt format" {
 }
 
 test "bcrypt phc format" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var hash_options = HashOptions{
         .params = .{ .rounds_log = 5 },
         .encoding = .phc,

lib/std/crypto/blake3.zig

@@ -200,7 +200,7 @@ const CompressGeneric = struct {
     }
 };
 
-const compress = if (builtin.cpu.arch == .x86_64)
+const compress = if (builtin.cpu.arch == .x86_64 and builtin.zig_backend != .stage2_x86_64)
     CompressVectorized.compress
 else
     CompressGeneric.compress;
@@ -682,6 +682,8 @@ fn testBlake3(hasher: *Blake3, input_len: usize, expected_hex: [262]u8) !void {
 }
 
 test "BLAKE3 reference test cases" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var hash_state = Blake3.init(.{});
     const hash = &hash_state;
     var keyed_hash_state = Blake3.init(.{ .key = reference_test.key.* });

lib/std/crypto/chacha20.zig

@@ -499,6 +499,8 @@ fn ChaChaNonVecImpl(comptime rounds_nb: usize) type {
 fn ChaChaImpl(comptime rounds_nb: usize) type {
     switch (builtin.cpu.arch) {
         .x86_64 => {
+            if (builtin.zig_backend == .stage2_x86_64) return ChaChaNonVecImpl(rounds_nb);
+
             const has_avx2 = std.Target.x86.featureSetHas(builtin.cpu.features, .avx2);
             const has_avx512f = std.Target.x86.featureSetHas(builtin.cpu.features, .avx512f);
             if (has_avx512f) return ChaChaVecImpl(rounds_nb, 4);
@@ -757,6 +759,8 @@ fn XChaChaPoly1305(comptime rounds_nb: usize) type {
 }
 
 test "chacha20 AEAD API" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const aeads = [_]type{ ChaCha20Poly1305, XChaCha20Poly1305 };
     const m = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";
     const ad = "Additional data";
@@ -778,6 +782,8 @@ test "chacha20 AEAD API" {
 
 // https://tools.ietf.org/html/rfc7539#section-2.4.2
 test "crypto.chacha20 test vector sunscreen" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0x6e, 0x2e, 0x35, 0x9a, 0x25, 0x68, 0xf9, 0x80,
         0x41, 0xba, 0x07, 0x28, 0xdd, 0x0d, 0x69, 0x81,
@@ -819,6 +825,8 @@ test "crypto.chacha20 test vector sunscreen" {
 
 // https://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04#section-7
 test "crypto.chacha20 test vector 1" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0x76, 0xb8, 0xe0, 0xad, 0xa0, 0xf1, 0x3d, 0x90,
         0x40, 0x5d, 0x6a, 0xe5, 0x53, 0x86, 0xbd, 0x28,
@@ -853,6 +861,8 @@ test "crypto.chacha20 test vector 1" {
 }
 
 test "crypto.chacha20 test vector 2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0x45, 0x40, 0xf0, 0x5a, 0x9f, 0x1f, 0xb2, 0x96,
         0xd7, 0x73, 0x6e, 0x7b, 0x20, 0x8e, 0x3c, 0x96,
@@ -887,6 +897,8 @@ test "crypto.chacha20 test vector 2" {
 }
 
 test "crypto.chacha20 test vector 3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0xde, 0x9c, 0xba, 0x7b, 0xf3, 0xd6, 0x9e, 0xf5,
         0xe7, 0x86, 0xdc, 0x63, 0x97, 0x3f, 0x65, 0x3a,
@@ -921,6 +933,8 @@ test "crypto.chacha20 test vector 3" {
 }
 
 test "crypto.chacha20 test vector 4" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0xef, 0x3f, 0xdf, 0xd6, 0xc6, 0x15, 0x78, 0xfb,
         0xf5, 0xcf, 0x35, 0xbd, 0x3d, 0xd3, 0x3b, 0x80,
@@ -955,6 +969,8 @@ test "crypto.chacha20 test vector 4" {
 }
 
 test "crypto.chacha20 test vector 5" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_result = [_]u8{
         0xf7, 0x98, 0xa1, 0x89, 0xf1, 0x95, 0xe6, 0x69,
         0x82, 0x10, 0x5f, 0xfb, 0x64, 0x0b, 0xb7, 0x75,
@@ -1027,6 +1043,8 @@ test "crypto.chacha20 test vector 5" {
 }
 
 test "seal" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         const m = "";
         const ad = "";
@@ -1077,6 +1095,8 @@ test "seal" {
 }
 
 test "open" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         const c = [_]u8{ 0xa0, 0x78, 0x4d, 0x7a, 0x47, 0x16, 0xf3, 0xfe, 0xb4, 0xf6, 0x4e, 0x7f, 0x4b, 0x39, 0xbf, 0x4 };
         const ad = "";
@@ -1141,6 +1161,8 @@ test "open" {
 }
 
 test "crypto.xchacha20" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{69} ** 32;
     const nonce = [_]u8{42} ** 24;
     const m = "Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it.";

lib/std/crypto/cmac.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const mem = std.mem;
 
@@ -93,6 +94,8 @@ pub fn Cmac(comptime BlockCipher: type) type {
 const testing = std.testing;
 
 test "CmacAes128 - Example 1: len = 0" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{
         0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
     };
@@ -106,6 +109,8 @@ test "CmacAes128 - Example 1: len = 0" {
 }
 
 test "CmacAes128 - Example 2: len = 16" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{
         0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
     };
@@ -121,6 +126,8 @@ test "CmacAes128 - Example 2: len = 16" {
 }
 
 test "CmacAes128 - Example 3: len = 40" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{
         0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
     };
@@ -138,6 +145,8 @@ test "CmacAes128 - Example 3: len = 40" {
 }
 
 test "CmacAes128 - Example 4: len = 64" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{
         0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
     };

lib/std/crypto/ecdsa.zig

@@ -372,7 +372,10 @@ pub fn Ecdsa(comptime Curve: type, comptime Hash: type) type {
 }
 
 test "ECDSA - Basic operations over EcdsaP384Sha384" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const Scheme = EcdsaP384Sha384;
     const kp = try Scheme.KeyPair.create(null);
@@ -388,7 +391,10 @@ test "ECDSA - Basic operations over EcdsaP384Sha384" {
 }
 
 test "ECDSA - Basic operations over Secp256k1" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const Scheme = EcdsaSecp256k1Sha256oSha256;
     const kp = try Scheme.KeyPair.create(null);
@@ -404,7 +410,10 @@ test "ECDSA - Basic operations over Secp256k1" {
 }
 
 test "ECDSA - Basic operations over EcdsaP384Sha256" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const Scheme = Ecdsa(crypto.ecc.P384, crypto.hash.sha2.Sha256);
     const kp = try Scheme.KeyPair.create(null);
@@ -420,7 +429,10 @@ test "ECDSA - Basic operations over EcdsaP384Sha256" {
 }
 
 test "ECDSA - Verifying a existing signature with EcdsaP384Sha256" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const Scheme = Ecdsa(crypto.ecc.P384, crypto.hash.sha2.Sha256);
     // zig fmt: off
@@ -464,7 +476,10 @@ const TestVector = struct {
 };
 
 test "ECDSA - Test vectors from Project Wycheproof" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const vectors = [_]TestVector{
         .{ .key = "042927b10512bae3eddcfe467828128bad2903269919f7086069c8c4df6c732838c7787964eaac00e5921fb1498a60f4606766b3d9685001558d1a974e7341513e", .msg = "313233343030", .sig = "304402202ba3a8be6b94d5ec80a6d9d1190a436effe50d85a1eee859b8cc6af9bd5c2e1802204cd60b855d442f5b3c7b11eb6c4e0ae7525fe710fab9aa7c77a67f79e6fadd76", .result = .valid },
@@ -878,7 +893,10 @@ fn tvTry(vector: TestVector) !void {
 }
 
 test "ECDSA - Sec1 encoding/decoding" {
-    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (builtin.zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const Scheme = EcdsaP384Sha384;
     const kp = try Scheme.KeyPair.create(null);

lib/std/crypto/ff.zig

@@ -912,7 +912,10 @@ const ct_unprotected = struct {
 };
 
 test {
-    if (@import("builtin").zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (@import("builtin").zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     const M = Modulus(256);
     const m = try M.fromPrimitive(u256, 3429938563481314093726330772853735541133072814650493833233);

lib/std/crypto/ghash_polyval.zig

@@ -422,6 +422,8 @@ fn Hash(comptime endian: std.builtin.Endian, comptime shift_key: bool) type {
 const htest = @import("test.zig");
 
 test "ghash" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{0x42} ** 16;
     const m = [_]u8{0x69} ** 256;
 
@@ -439,6 +441,8 @@ test "ghash" {
 }
 
 test "ghash2" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var key: [16]u8 = undefined;
     var i: usize = 0;
     while (i < key.len) : (i += 1) {
@@ -472,6 +476,8 @@ test "ghash2" {
 }
 
 test "polyval" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{0x42} ** 16;
     const m = [_]u8{0x69} ** 256;
 

lib/std/crypto/hash_composition.zig

@@ -65,6 +65,8 @@ pub const Sha384oSha384 = Composition(sha2.Sha384, sha2.Sha384);
 pub const Sha512oSha512 = Composition(sha2.Sha512, sha2.Sha512);
 
 test "Hash composition" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Sha256 = sha2.Sha256;
     const msg = "test";
 

lib/std/crypto/hkdf.zig

@@ -72,6 +72,8 @@ pub fn Hkdf(comptime Hmac: type) type {
 const htest = @import("test.zig");
 
 test "Hkdf" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const ikm = [_]u8{0x0b} ** 22;
     const salt = [_]u8{ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c };
     const context = [_]u8{ 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9 };

lib/std/crypto/kyber_d00.zig

@@ -553,6 +553,8 @@ const inv_ntt_reductions = [_]i16{
 };
 
 test "invNTTReductions bounds" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Checks whether the reductions proposed by invNTTReductions
     // don't overflow during invNTT().
     var xs = [_]i32{1} ** 256; // start at |x| ≤ q
@@ -656,6 +658,8 @@ fn montReduce(x: i32) i16 {
 }
 
 test "Test montReduce" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var rnd = RndGen.init(0);
     for (0..1000) |_| {
         const bound = comptime @as(i32, Q) * (1 << 15);
@@ -674,6 +678,8 @@ fn feToMont(x: i16) i16 {
 }
 
 test "Test feToMont" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var x: i32 = -(1 << 15);
     while (x < 1 << 15) : (x += 1) {
         const y = feToMont(@as(i16, @intCast(x)));
@@ -707,6 +713,8 @@ fn feBarrettReduce(x: i16) i16 {
 }
 
 test "Test Barrett reduction" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var x: i32 = -(1 << 15);
     while (x < 1 << 15) : (x += 1) {
         var y1 = feBarrettReduce(@as(i16, @intCast(x)));
@@ -727,6 +735,8 @@ fn csubq(x: i16) i16 {
 }
 
 test "Test csubq" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var x: i32 = -29439;
     while (x < 1 << 15) : (x += 1) {
         const y1 = csubq(@as(i16, @intCast(x)));
@@ -1466,6 +1476,8 @@ fn cmov(comptime len: usize, dst: *[len]u8, src: [len]u8, b: u1) void {
 }
 
 test "MulHat" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var rnd = RndGen.init(0);
 
     for (0..100) |_| {
@@ -1497,6 +1509,8 @@ test "MulHat" {
 }
 
 test "NTT" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var rnd = RndGen.init(0);
 
     for (0..1000) |_| {
@@ -1520,6 +1534,8 @@ test "NTT" {
 }
 
 test "Compression" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var rnd = RndGen.init(0);
     inline for (.{ 1, 4, 5, 10, 11 }) |d| {
         for (0..1000) |_| {
@@ -1532,6 +1548,8 @@ test "Compression" {
 }
 
 test "noise" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [32]u8 = undefined;
     for (&seed, 0..) |*s, i| {
         s.* = @as(u8, @intCast(i));
@@ -1578,6 +1596,8 @@ test "noise" {
 }
 
 test "uniform sampling" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [32]u8 = undefined;
     for (&seed, 0..) |*s, i| {
         s.* = @as(u8, @intCast(i));
@@ -1611,6 +1631,8 @@ test "uniform sampling" {
 }
 
 test "Polynomial packing" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var rnd = RndGen.init(0);
 
     for (0..1000) |_| {
@@ -1620,6 +1642,8 @@ test "Polynomial packing" {
 }
 
 test "Test inner PKE" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [32]u8 = undefined;
     var pt: [32]u8 = undefined;
     for (&seed, &pt, 0..) |*s, *p, i| {
@@ -1641,6 +1665,8 @@ test "Test inner PKE" {
 }
 
 test "Test happy flow" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var seed: [64]u8 = undefined;
     for (&seed, 0..) |*s, i| {
         s.* = @as(u8, @intCast(i));
@@ -1667,6 +1693,8 @@ test "Test happy flow" {
 const sha2 = crypto.hash.sha2;
 
 test "NIST KAT test" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for (.{
         .{ Kyber512, "e9c2bd37133fcb40772f81559f14b1f58dccd1c816701be9ba6214d43baf4547" },
         .{ Kyber1024, "89248f2f33f7f4f7051729111f3049c409a933ec904aedadf035f30fa5646cd5" },

lib/std/crypto/pbkdf2.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const mem = std.mem;
 const maxInt = std.math.maxInt;
 const OutputTooLongError = std.crypto.errors.OutputTooLongError;
@@ -151,6 +152,8 @@ const HmacSha1 = std.crypto.auth.hmac.HmacSha1;
 // RFC 6070 PBKDF2 HMAC-SHA1 Test Vectors
 
 test "RFC 6070 one iteration" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = "password";
     const s = "salt";
     const c = 1;
@@ -166,6 +169,8 @@ test "RFC 6070 one iteration" {
 }
 
 test "RFC 6070 two iterations" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = "password";
     const s = "salt";
     const c = 2;
@@ -181,6 +186,8 @@ test "RFC 6070 two iterations" {
 }
 
 test "RFC 6070 4096 iterations" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = "password";
     const s = "salt";
     const c = 4096;
@@ -196,6 +203,8 @@ test "RFC 6070 4096 iterations" {
 }
 
 test "RFC 6070 16,777,216 iterations" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // These iteration tests are slow so we always skip them. Results have been verified.
     if (true) {
         return error.SkipZigTest;
@@ -216,6 +225,8 @@ test "RFC 6070 16,777,216 iterations" {
 }
 
 test "RFC 6070 multi-block salt and password" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = "passwordPASSWORDpassword";
     const s = "saltSALTsaltSALTsaltSALTsaltSALTsalt";
     const c = 4096;
@@ -231,6 +242,8 @@ test "RFC 6070 multi-block salt and password" {
 }
 
 test "RFC 6070 embedded NUL" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const p = "pass\x00word";
     const s = "sa\x00lt";
     const c = 4096;
@@ -246,6 +259,8 @@ test "RFC 6070 embedded NUL" {
 }
 
 test "Very large dk_len" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // This test allocates 8GB of memory and is expected to take several hours to run.
     if (true) {
         return error.SkipZigTest;

lib/std/crypto/pcurves/p256.zig

@@ -478,5 +478,7 @@ pub const AffineCoordinates = struct {
 };
 
 test {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     _ = @import("tests/p256.zig");
 }

lib/std/crypto/pcurves/p384.zig

@@ -478,7 +478,10 @@ pub const AffineCoordinates = struct {
 };
 
 test {
-    if (@import("builtin").zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (@import("builtin").zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     _ = @import("tests/p384.zig");
 }

lib/std/crypto/pcurves/secp256k1.zig

@@ -556,7 +556,10 @@ pub const AffineCoordinates = struct {
 };
 
 test {
-    if (@import("builtin").zig_backend == .stage2_c) return error.SkipZigTest;
+    switch (@import("builtin").zig_backend) {
+        .stage2_c, .stage2_x86_64 => return error.SkipZigTest,
+        else => {},
+    }
 
     _ = @import("tests/secp256k1.zig");
 }

lib/std/crypto/phc_encoding.zig

@@ -1,6 +1,7 @@
 // https://github.com/P-H-C/phc-string-format
 
 const std = @import("std");
+const builtin = @import("builtin");
 const fmt = std.fmt;
 const io = std.io;
 const mem = std.mem;
@@ -263,6 +264,8 @@ fn kvSplit(str: []const u8) !struct { key: []const u8, value: []const u8 } {
 }
 
 test "phc format - encoding/decoding" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Input = struct {
         str: []const u8,
         HashResult: type,
@@ -348,18 +351,24 @@ test "phc format - encoding/decoding" {
 }
 
 test "phc format - empty input string" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s = "";
     const v = deserialize(struct { alg_id: []const u8 }, s);
     try std.testing.expectError(Error.InvalidEncoding, v);
 }
 
 test "phc format - hash without salt" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s = "$scrypt";
     const v = deserialize(struct { alg_id: []const u8, hash: BinValue(16) }, s);
     try std.testing.expectError(Error.InvalidEncoding, v);
 }
 
 test "phc format - calcSize" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s = "$scrypt$v=1$ln=15,r=8,p=1$c2FsdHNhbHQ$dGVzdHBhc3M";
     const v = try deserialize(struct {
         alg_id: []const u8,

lib/std/crypto/poly1305.zig

@@ -196,6 +196,8 @@ pub const Poly1305 = struct {
 };
 
 test "poly1305 rfc7439 vector1" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const expected_mac = "\xa8\x06\x1d\xc1\x30\x51\x36\xc6\xc2\x2b\x8b\xaf\x0c\x01\x27\xa9";
 
     const msg = "Cryptographic Forum Research Group";

lib/std/crypto/salsa20.zig

@@ -555,6 +555,8 @@ pub const SealedBox = struct {
 const htest = @import("test.zig");
 
 test "(x)salsa20" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{0x69} ** 32;
     const nonce = [_]u8{0x42} ** 8;
     const msg = [_]u8{0} ** 20;
@@ -569,6 +571,8 @@ test "(x)salsa20" {
 }
 
 test "xsalsa20poly1305" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var msg: [100]u8 = undefined;
     var msg2: [msg.len]u8 = undefined;
     var c: [msg.len]u8 = undefined;
@@ -584,6 +588,8 @@ test "xsalsa20poly1305" {
 }
 
 test "xsalsa20poly1305 secretbox" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var msg: [100]u8 = undefined;
     var msg2: [msg.len]u8 = undefined;
     var key: [XSalsa20Poly1305.key_length]u8 = undefined;
@@ -598,6 +604,8 @@ test "xsalsa20poly1305 secretbox" {
 }
 
 test "xsalsa20poly1305 box" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var msg: [100]u8 = undefined;
     var msg2: [msg.len]u8 = undefined;
     var nonce: [Box.nonce_length]u8 = undefined;
@@ -612,6 +620,8 @@ test "xsalsa20poly1305 box" {
 }
 
 test "xsalsa20poly1305 sealedbox" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var msg: [100]u8 = undefined;
     var msg2: [msg.len]u8 = undefined;
     var boxed: [msg.len + SealedBox.seal_length]u8 = undefined;
@@ -623,6 +633,8 @@ test "xsalsa20poly1305 sealedbox" {
 }
 
 test "secretbox twoblocks" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const key = [_]u8{ 0xc9, 0xc9, 0x4d, 0xcf, 0x68, 0xbe, 0x00, 0xe4, 0x7f, 0xe6, 0x13, 0x26, 0xfc, 0xc4, 0x2f, 0xd0, 0xdb, 0x93, 0x91, 0x1c, 0x09, 0x94, 0x89, 0xe1, 0x1b, 0x88, 0x63, 0x18, 0x86, 0x64, 0x8b, 0x7b };
     const nonce = [_]u8{ 0xa4, 0x33, 0xe9, 0x0a, 0x07, 0x68, 0x6e, 0x9a, 0x2b, 0x6d, 0xd4, 0x59, 0x04, 0x72, 0x3e, 0xd3, 0x8a, 0x67, 0x55, 0xc7, 0x9e, 0x3e, 0x77, 0xdc };
     const msg = [_]u8{'a'} ** 97;

lib/std/crypto/scrypt.zig

@@ -3,6 +3,7 @@
 // https://github.com/Tarsnap/scrypt
 
 const std = @import("std");
+const builtin = @import("builtin");
 const crypto = std.crypto;
 const fmt = std.fmt;
 const io = std.io;
@@ -683,6 +684,8 @@ test "unix-scrypt" {
 }
 
 test "crypt format" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const str = "$7$C6..../....SodiumChloride$kBGj9fHznVYFQMEn/qDCfrDevf9YDtcDdKvEqHJLV8D";
     const params = try crypt_format.deserialize(crypt_format.HashResult(32), str);
     var buf: [str.len]u8 = undefined;
@@ -691,6 +694,8 @@ test "crypt format" {
 }
 
 test "kdf fast" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const TestVector = struct {
         password: []const u8,
         salt: []const u8,

lib/std/crypto/sha2.zig

@@ -238,7 +238,7 @@ fn Sha2x32(comptime params: Sha2Params32) type {
                         return;
                     },
                     // C backend doesn't currently support passing vectors to inline asm.
-                    .x86_64 => if (builtin.zig_backend != .stage2_c and comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .sha, .avx2 })) {
+                    .x86_64 => if (builtin.zig_backend != .stage2_c and builtin.zig_backend != .stage2_x86_64 and comptime std.Target.x86.featureSetHasAll(builtin.cpu.features, .{ .sha, .avx2 })) {
                         var x: v4u32 = [_]u32{ d.s[5], d.s[4], d.s[1], d.s[0] };
                         var y: v4u32 = [_]u32{ d.s[7], d.s[6], d.s[3], d.s[2] };
                         const s_v = @as(*[16]v4u32, @ptrCast(&s));
@@ -406,12 +406,16 @@ fn Sha2x32(comptime params: Sha2Params32) type {
 }
 
 test "sha224 single" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try htest.assertEqualHash(Sha224, "d14a028c2a3a2bc9476102bb288234c415a2b01f828ea62ac5b3e42f", "");
     try htest.assertEqualHash(Sha224, "23097d223405d8228642a477bda255b32aadbce4bda0b3f7e36c9da7", "abc");
     try htest.assertEqualHash(Sha224, "c97ca9a559850ce97a04a96def6d99a9e0e0e2ab14e6b8df265fc0b3", "abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu");
 }
 
 test "sha224 streaming" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var h = Sha224.init(.{});
     var out: [28]u8 = undefined;
 
@@ -432,12 +436,16 @@ test "sha224 streaming" {
 }
 
 test "sha256 single" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try htest.assertEqualHash(Sha256, "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855", "");
     try htest.assertEqualHash(Sha256, "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad", "abc");
     try htest.assertEqualHash(Sha256, "cf5b16a778af8380036ce59e7b0492370b249b11e8f07a51afac45037afee9d1", "abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu");
 }
 
 test "sha256 streaming" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var h = Sha256.init(.{});
     var out: [32]u8 = undefined;
 
@@ -458,6 +466,8 @@ test "sha256 streaming" {
 }
 
 test "sha256 aligned final" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var block = [_]u8{0} ** Sha256.block_length;
     var out: [Sha256.digest_length]u8 = undefined;
 

lib/std/crypto/utils.zig

@@ -149,6 +149,8 @@ test "crypto.utils.timingSafeEql" {
 }
 
 test "crypto.utils.timingSafeEql (vectors)" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var a: [100]u8 = undefined;
     var b: [100]u8 = undefined;
     random.bytes(a[0..]);

lib/std/debug.zig

@@ -2513,6 +2513,8 @@ pub fn dumpStackPointerAddr(prefix: []const u8) void {
 }
 
 test "manage resources correctly" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
     if (builtin.os.tag == .windows) {

lib/std/dwarf/expressions.zig

@@ -1054,6 +1054,8 @@ fn isOpcodeRegisterLocation(opcode: u8) bool {
 
 const testing = std.testing;
 test "DWARF expressions" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
 
     const options = ExpressionOptions{};

lib/std/fifo.zig

@@ -505,6 +505,8 @@ test "LinearFifo(u8, .Dynamic)" {
 }
 
 test "LinearFifo" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for ([_]type{ u1, u8, u16, u64 }) |T| {
         inline for ([_]LinearFifoBufferType{ LinearFifoBufferType{ .Static = 32 }, .Slice, .Dynamic }) |bt| {
             const FifoType = LinearFifo(T, bt);

lib/std/fmt.zig

@@ -2129,6 +2129,8 @@ test "int.small" {
 }
 
 test "int.specifier" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         const value: u8 = 'a';
         try expectFmt("u8: a\n", "u8: {c}\n", .{value});
@@ -2179,6 +2181,8 @@ test "int.padded" {
 }
 
 test "buffer" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         var buf1: [32]u8 = undefined;
         var fbs = std.io.fixedBufferStream(&buf1);
@@ -2375,6 +2379,8 @@ test "float.scientific" {
 }
 
 test "float.scientific.precision" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("f64: 1.40971e-42", "f64: {e:.5}", .{@as(f64, 1.409706e-42)});
     try expectFmt("f64: 1.00000e-09", "f64: {e:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 814313563))))});
     try expectFmt("f64: 7.81250e-03", "f64: {e:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1006632960))))});
@@ -2435,6 +2441,8 @@ test "float.hexadecimal" {
 }
 
 test "float.hexadecimal.precision" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("f16: 0x1.5p-2", "f16: {x:.1}", .{@as(f16, 1.0 / 3.0)});
     try expectFmt("f32: 0x1.555p-2", "f32: {x:.3}", .{@as(f32, 1.0 / 3.0)});
     try expectFmt("f64: 0x1.55555p-2", "f64: {x:.5}", .{@as(f64, 1.0 / 3.0)});
@@ -2449,6 +2457,8 @@ test "float.hexadecimal.precision" {
 }
 
 test "float.decimal" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("f64: 152314000000000000000000000000", "f64: {d}", .{@as(f64, 1.52314e+29)});
     try expectFmt("f32: 0", "f32: {d}", .{@as(f32, 0.0)});
     try expectFmt("f32: 0", "f32: {d:.0}", .{@as(f32, 0.0)});
@@ -2472,6 +2482,8 @@ test "float.decimal" {
 }
 
 test "float.libc.sanity" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 916964781))))});
     try expectFmt("f64: 0.00001", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 925353389))))});
     try expectFmt("f64: 0.10000", "f64: {d:.5}", .{@as(f64, @as(f32, @bitCast(@as(u32, 1036831278))))});
@@ -2491,6 +2503,8 @@ test "float.libc.sanity" {
 }
 
 test "custom" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Vec2 = struct {
         const SelfType = @This();
         x: f32,
@@ -2669,6 +2683,8 @@ test "formatFloatValue with comptime_float" {
 }
 
 test "formatType max_depth" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Vec2 = struct {
         const SelfType = @This();
         x: f32,
@@ -2735,6 +2751,8 @@ test "formatType max_depth" {
 }
 
 test "positional" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("2 1 0", "{2} {1} {0}", .{ @as(usize, 0), @as(usize, 1), @as(usize, 2) });
     try expectFmt("2 1 0", "{2} {1} {}", .{ @as(usize, 0), @as(usize, 1), @as(usize, 2) });
     try expectFmt("0 0", "{0} {0}", .{@as(usize, 0)});
@@ -2743,14 +2761,20 @@ test "positional" {
 }
 
 test "positional with specifier" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("10.0", "{0d:.1}", .{@as(f64, 9.999)});
 }
 
 test "positional/alignment/width/precision" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectFmt("10.0", "{0d: >3.1}", .{@as(f64, 9.999)});
 }
 
 test "vector" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (builtin.target.cpu.arch == .riscv64) {
         // https://github.com/ziglang/zig/issues/4486
         return error.SkipZigTest;

lib/std/fmt/parse_float.zig

@@ -1,8 +1,8 @@
 pub const parseFloat = @import("parse_float/parse_float.zig").parseFloat;
 pub const ParseFloatError = @import("parse_float/parse_float.zig").ParseFloatError;
 
-const builtin = @import("builtin");
 const std = @import("std");
+const builtin = @import("builtin");
 const math = std.math;
 const testing = std.testing;
 const expect = testing.expect;
@@ -14,6 +14,8 @@ const epsilon = 1e-7;
 // See https://github.com/tiehuis/parse-number-fxx-test-data for a wider-selection of test-data.
 
 test "fmt.parseFloat" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for ([_]type{ f16, f32, f64, f128 }) |T| {
         try testing.expectError(error.InvalidCharacter, parseFloat(T, ""));
         try testing.expectError(error.InvalidCharacter, parseFloat(T, "   1"));
@@ -70,6 +72,8 @@ test "fmt.parseFloat" {
 }
 
 test "fmt.parseFloat nan and inf" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     inline for ([_]type{ f16, f32, f64, f128 }) |T| {
         const Z = std.meta.Int(.unsigned, @typeInfo(T).Float.bits);
 
@@ -80,16 +84,22 @@ test "fmt.parseFloat nan and inf" {
 }
 
 test "fmt.parseFloat #11169" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try expectEqual(try parseFloat(f128, "9007199254740993.0"), 9007199254740993.0);
 }
 
 test "fmt.parseFloat hex.special" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expect(math.isNan(try parseFloat(f32, "nAn")));
     try testing.expect(math.isPositiveInf(try parseFloat(f32, "iNf")));
     try testing.expect(math.isPositiveInf(try parseFloat(f32, "+Inf")));
     try testing.expect(math.isNegativeInf(try parseFloat(f32, "-iNf")));
 }
 test "fmt.parseFloat hex.zero" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectEqual(@as(f32, 0.0), try parseFloat(f32, "0x0"));
     try testing.expectEqual(@as(f32, 0.0), try parseFloat(f32, "-0x0"));
     try testing.expectEqual(@as(f32, 0.0), try parseFloat(f32, "0x0p42"));
@@ -98,6 +108,8 @@ test "fmt.parseFloat hex.zero" {
 }
 
 test "fmt.parseFloat hex.f16" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectEqual(try parseFloat(f16, "0x1p0"), 1.0);
     try testing.expectEqual(try parseFloat(f16, "-0x1p-1"), -0.5);
     try testing.expectEqual(try parseFloat(f16, "0x10p+10"), 16384.0);
@@ -114,6 +126,8 @@ test "fmt.parseFloat hex.f16" {
 }
 
 test "fmt.parseFloat hex.f32" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectError(error.InvalidCharacter, parseFloat(f32, "0x"));
     try testing.expectEqual(try parseFloat(f32, "0x1p0"), 1.0);
     try testing.expectEqual(try parseFloat(f32, "-0x1p-1"), -0.5);
@@ -148,6 +162,8 @@ test "fmt.parseFloat hex.f64" {
     try testing.expectEqual(try parseFloat(f64, "-0x1p-1074"), -math.floatTrueMin(f64));
 }
 test "fmt.parseFloat hex.f128" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectEqual(try parseFloat(f128, "0x1p0"), 1.0);
     try testing.expectEqual(try parseFloat(f128, "-0x1p-1"), -0.5);
     try testing.expectEqual(try parseFloat(f128, "0x10p+10"), 16384.0);

lib/std/fs.zig

@@ -3244,13 +3244,15 @@ fn copy_file(fd_in: os.fd_t, fd_out: os.fd_t, maybe_size: ?u64) CopyFileRawError
 }
 
 test {
-    if (builtin.os.tag != .wasi) {
-        _ = &makeDirAbsolute;
-        _ = &makeDirAbsoluteZ;
-        _ = &copyFileAbsolute;
-        _ = &updateFileAbsolute;
+    if (builtin.zig_backend != .stage2_x86_64) {
+        if (builtin.os.tag != .wasi) {
+            _ = &makeDirAbsolute;
+            _ = &makeDirAbsoluteZ;
+            _ = &copyFileAbsolute;
+            _ = &updateFileAbsolute;
+        }
+        _ = &Dir.copyFile;
     }
-    _ = &Dir.copyFile;
     _ = @import("fs/test.zig");
     _ = @import("fs/path.zig");
     _ = @import("fs/file.zig");

lib/std/fs/test.zig

@@ -124,6 +124,8 @@ fn testWithAllSupportedPathTypes(test_func: anytype) !void {
 }
 
 test "Dir.readLink" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             // Create some targets
@@ -161,6 +163,8 @@ fn testReadLink(dir: Dir, target_path: []const u8, symlink_path: []const u8) !vo
 }
 
 test "relative symlink to parent directory" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -178,6 +182,8 @@ test "relative symlink to parent directory" {
 }
 
 test "openDir" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const allocator = ctx.arena.allocator();
@@ -196,6 +202,8 @@ test "openDir" {
 test "accessAbsolute" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -214,6 +222,8 @@ test "accessAbsolute" {
 test "openDirAbsolute" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -252,6 +262,8 @@ test "openDir non-cwd parent .." {
         else => {},
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -273,6 +285,8 @@ test "openDir non-cwd parent .." {
 test "readLinkAbsolute" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -323,6 +337,8 @@ fn testReadLinkAbsolute(target_path: []const u8, symlink_path: []const u8) !void
 }
 
 test "Dir.Iterator" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpIterableDir(.{});
     defer tmp_dir.cleanup();
 
@@ -353,6 +369,8 @@ test "Dir.Iterator" {
 }
 
 test "Dir.Iterator many entries" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpIterableDir(.{});
     defer tmp_dir.cleanup();
 
@@ -388,6 +406,8 @@ test "Dir.Iterator many entries" {
 }
 
 test "Dir.Iterator twice" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpIterableDir(.{});
     defer tmp_dir.cleanup();
 
@@ -421,6 +441,8 @@ test "Dir.Iterator twice" {
 }
 
 test "Dir.Iterator reset" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpIterableDir(.{});
     defer tmp_dir.cleanup();
 
@@ -457,6 +479,8 @@ test "Dir.Iterator reset" {
 }
 
 test "Dir.Iterator but dir is deleted during iteration" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = std.testing.tmpDir(.{});
     defer tmp.cleanup();
 
@@ -499,6 +523,8 @@ fn contains(entries: *const std.ArrayList(IterableDir.Entry), el: IterableDir.En
 test "Dir.realpath smoke test" {
     if (!comptime std.os.isGetFdPathSupportedOnTarget(builtin.os)) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const allocator = ctx.arena.allocator();
@@ -549,6 +575,8 @@ test "Dir.realpath smoke test" {
 }
 
 test "readAllAlloc" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpDir(.{});
     defer tmp_dir.cleanup();
 
@@ -585,6 +613,8 @@ test "Dir.statFile" {
     // TODO: Re-enable once https://github.com/ziglang/zig/issues/17034 is solved
     if (builtin.os.tag == .linux and builtin.link_libc and builtin.abi == .gnu) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_file_name = try ctx.transformPath("test_file");
@@ -600,6 +630,8 @@ test "Dir.statFile" {
 }
 
 test "directory operations on files" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_file_name = try ctx.transformPath("test_file");
@@ -629,6 +661,8 @@ test "file operations on directories" {
     // TODO: fix this test on FreeBSD. https://github.com/ziglang/zig/issues/1759
     if (builtin.os.tag == .freebsd) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_dir_name = try ctx.transformPath("test_dir");
@@ -676,6 +710,8 @@ test "makeOpenPath parent dirs do not exist" {
 }
 
 test "deleteDir" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_dir_path = try ctx.transformPath("test_dir");
@@ -697,6 +733,8 @@ test "deleteDir" {
 }
 
 test "Dir.rename files" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             // Rename on Windows can hit intermittent AccessDenied errors
@@ -739,6 +777,8 @@ test "Dir.rename files" {
 }
 
 test "Dir.rename directories" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             // Rename on Windows can hit intermittent AccessDenied errors
@@ -780,6 +820,8 @@ test "Dir.rename directory onto empty dir" {
     // TODO: Fix on Windows, see https://github.com/ziglang/zig/issues/6364
     if (builtin.os.tag == .windows) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_dir_path = try ctx.transformPath("test_dir");
@@ -801,6 +843,8 @@ test "Dir.rename directory onto non-empty dir" {
     // TODO: Fix on Windows, see https://github.com/ziglang/zig/issues/6364
     if (builtin.os.tag == .windows) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_dir_path = try ctx.transformPath("test_dir");
@@ -827,6 +871,8 @@ test "Dir.rename file <-> dir" {
     // TODO: Fix on Windows, see https://github.com/ziglang/zig/issues/6364
     if (builtin.os.tag == .windows) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const test_file_path = try ctx.transformPath("test_file");
@@ -842,6 +888,8 @@ test "Dir.rename file <-> dir" {
 }
 
 test "rename" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir1 = tmpDir(.{});
     defer tmp_dir1.cleanup();
 
@@ -864,6 +912,8 @@ test "rename" {
 test "renameAbsolute" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp_dir = tmpDir(.{});
     defer tmp_dir.cleanup();
 
@@ -922,6 +972,8 @@ test "openSelfExe" {
 }
 
 test "makePath, put some files in it, deleteTree" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const allocator = ctx.arena.allocator();
@@ -938,6 +990,8 @@ test "makePath, put some files in it, deleteTree" {
 }
 
 test "makePath, put some files in it, deleteTreeMinStackSize" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const allocator = ctx.arena.allocator();
@@ -956,6 +1010,8 @@ test "makePath, put some files in it, deleteTreeMinStackSize" {
 test "makePath in a directory that no longer exists" {
     if (builtin.os.tag == .windows) return error.SkipZigTest; // Windows returns FileBusy if attempting to remove an open dir
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
     try tmp.parent_dir.deleteTree(&tmp.sub_path);
@@ -987,6 +1043,8 @@ fn testFilenameLimits(iterable_dir: IterableDir, maxed_filename: []const u8) !vo
 }
 
 test "max file name component lengths" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpIterableDir(.{});
     defer tmp.cleanup();
 
@@ -1008,6 +1066,8 @@ test "max file name component lengths" {
 }
 
 test "writev, readv" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1050,6 +1110,8 @@ test "writev, readv" {
 }
 
 test "pwritev, preadv" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1091,6 +1153,8 @@ test "pwritev, preadv" {
 }
 
 test "access file" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const dir_path = try ctx.transformPath("os_test_tmp");
@@ -1107,6 +1171,8 @@ test "access file" {
 }
 
 test "sendfile" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1172,6 +1238,8 @@ test "sendfile" {
 }
 
 test "copyRangeAll" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1198,6 +1266,8 @@ test "copyRangeAll" {
 }
 
 test "copyFile" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const data = "u6wj+JmdF3qHsFPE BUlH2g4gJCmEz0PP";
@@ -1228,6 +1298,8 @@ fn expectFileContents(dir: Dir, file_path: []const u8, data: []const u8) !void {
 }
 
 test "AtomicFile" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const allocator = ctx.arena.allocator();
@@ -1254,6 +1326,8 @@ test "AtomicFile" {
 test "open file with exclusive nonblocking lock twice" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const filename = try ctx.transformPath("file_nonblocking_lock_test.txt");
@@ -1270,6 +1344,8 @@ test "open file with exclusive nonblocking lock twice" {
 test "open file with shared and exclusive nonblocking lock" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const filename = try ctx.transformPath("file_nonblocking_lock_test.txt");
@@ -1286,6 +1362,8 @@ test "open file with shared and exclusive nonblocking lock" {
 test "open file with exclusive and shared nonblocking lock" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testWithAllSupportedPathTypes(struct {
         fn impl(ctx: *TestContext) !void {
             const filename = try ctx.transformPath("file_nonblocking_lock_test.txt");
@@ -1300,6 +1378,8 @@ test "open file with exclusive and shared nonblocking lock" {
 }
 
 test "open file with exclusive lock twice, make sure second lock waits" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (builtin.single_threaded) return error.SkipZigTest;
 
     if (std.io.is_async) {
@@ -1350,6 +1430,8 @@ test "open file with exclusive lock twice, make sure second lock waits" {
 test "open file with exclusive nonblocking lock twice (absolute paths)" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var random_bytes: [12]u8 = undefined;
     std.crypto.random.bytes(&random_bytes);
 
@@ -1384,6 +1466,8 @@ test "open file with exclusive nonblocking lock twice (absolute paths)" {
 test "walker" {
     if (builtin.os.tag == .wasi and builtin.link_libc) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpIterableDir(.{});
     defer tmp.cleanup();
 
@@ -1437,6 +1521,8 @@ test "walker" {
 test "walker without fully iterating" {
     if (builtin.os.tag == .wasi and builtin.link_libc) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpIterableDir(.{});
     defer tmp.cleanup();
 
@@ -1460,6 +1546,8 @@ test "walker without fully iterating" {
 test ". and .. in fs.Dir functions" {
     if (builtin.os.tag == .wasi and builtin.link_libc) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (builtin.os.tag == .windows and builtin.cpu.arch == .aarch64) {
         // https://github.com/ziglang/zig/issues/17134
         return error.SkipZigTest;
@@ -1500,6 +1588,8 @@ test ". and .. in fs.Dir functions" {
 test ". and .. in absolute functions" {
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1545,6 +1635,8 @@ test "chmod" {
     if (builtin.os.tag == .windows or builtin.os.tag == .wasi)
         return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1567,6 +1659,8 @@ test "chown" {
     if (builtin.os.tag == .windows or builtin.os.tag == .wasi)
         return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1582,6 +1676,8 @@ test "chown" {
 }
 
 test "File.Metadata" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1600,6 +1696,8 @@ test "File.Permissions" {
     if (builtin.os.tag == .wasi)
         return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1626,6 +1724,8 @@ test "File.PermissionsUnix" {
     if (builtin.os.tag == .windows or builtin.os.tag == .wasi)
         return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1661,6 +1761,8 @@ test "delete a read-only file on windows" {
     if (builtin.os.tag != .windows)
         return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
 
@@ -1691,6 +1793,8 @@ test "delete a read-only file on windows" {
 test "delete a setAsCwd directory on Windows" {
     if (builtin.os.tag != .windows) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     // Set tmp dir as current working directory.
     try tmp.dir.setAsCwd();

lib/std/hash/auto_hash.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const assert = std.debug.assert;
+const builtin = @import("builtin");
 const mem = std.mem;
 const meta = std.meta;
 
@@ -252,6 +253,8 @@ test "typeContainsSlice" {
 }
 
 test "hash pointer" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const array = [_]u32{ 123, 123, 123 };
     const a = &array[0];
     const b = &array[1];
@@ -272,6 +275,8 @@ test "hash pointer" {
 }
 
 test "hash slice shallow" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Allocate one array dynamically so that we're assured it is not merged
     // with the other by the optimization passes.
     const array1 = try std.testing.allocator.create([6]u32);
@@ -290,6 +295,8 @@ test "hash slice shallow" {
 }
 
 test "hash slice deep" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Allocate one array dynamically so that we're assured it is not merged
     // with the other by the optimization passes.
     const array1 = try std.testing.allocator.create([6]u32);
@@ -306,6 +313,8 @@ test "hash slice deep" {
 }
 
 test "hash struct deep" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Foo = struct {
         a: u32,
         b: u16,
@@ -345,6 +354,8 @@ test "hash struct deep" {
 }
 
 test "testHash optional" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a: ?u32 = 123;
     const b: ?u32 = null;
     try testing.expectEqual(testHash(a), testHash(@as(u32, 123)));
@@ -353,6 +364,8 @@ test "testHash optional" {
 }
 
 test "testHash array" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a = [_]u32{ 1, 2, 3 };
     const h = testHash(a);
     var hasher = Wyhash.init(0);
@@ -369,6 +382,8 @@ test "testHash multi-dimensional array" {
 }
 
 test "testHash struct" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Foo = struct {
         a: u32 = 1,
         b: u32 = 2,
@@ -384,6 +399,8 @@ test "testHash struct" {
 }
 
 test "testHash union" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Foo = union(enum) {
         A: u32,
         B: bool,
@@ -408,6 +425,8 @@ test "testHash union" {
 }
 
 test "testHash vector" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const a: @Vector(4, u32) = [_]u32{ 1, 2, 3, 4 };
     const b: @Vector(4, u32) = [_]u32{ 1, 2, 3, 5 };
     try testing.expect(testHash(a) == testHash(a));
@@ -420,6 +439,8 @@ test "testHash vector" {
 }
 
 test "testHash error union" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Errors = error{Test};
     const Foo = struct {
         a: u32 = 1,

lib/std/hash/wyhash.zig

@@ -242,6 +242,8 @@ test "smhasher" {
 }
 
 test "iterative api" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try verify.iterativeApi(Wyhash);

lib/std/hash/xxhash.zig

@@ -803,6 +803,8 @@ fn testExpect(comptime H: type, seed: anytype, input: []const u8, expected: u64)
 }
 
 test "xxhash3" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const H = XxHash3;
     // Non-Seeded Tests
     try testExpect(H, 0, "", 0x2d06800538d394c2);
@@ -834,6 +836,8 @@ test "xxhash3" {
 }
 
 test "xxhash3 smhasher" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try expectEqual(verify.smhasher(XxHash3.hash), 0x9a636405);
@@ -845,6 +849,8 @@ test "xxhash3 smhasher" {
 }
 
 test "xxhash3 iterative api" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try verify.iterativeApi(XxHash3);
@@ -856,6 +862,8 @@ test "xxhash3 iterative api" {
 }
 
 test "xxhash64" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const H = XxHash64;
     try testExpect(H, 0, "", 0xef46db3751d8e999);
     try testExpect(H, 0, "a", 0xd24ec4f1a98c6e5b);
@@ -867,6 +875,8 @@ test "xxhash64" {
 }
 
 test "xxhash64 smhasher" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try expectEqual(verify.smhasher(XxHash64.hash), 0x024B7CF4);
@@ -878,6 +888,8 @@ test "xxhash64 smhasher" {
 }
 
 test "xxhash64 iterative api" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try verify.iterativeApi(XxHash64);
@@ -889,6 +901,8 @@ test "xxhash64 iterative api" {
 }
 
 test "xxhash32" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const H = XxHash32;
 
     try testExpect(H, 0, "", 0x02cc5d05);
@@ -901,6 +915,8 @@ test "xxhash32" {
 }
 
 test "xxhash32 smhasher" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try expectEqual(verify.smhasher(XxHash32.hash), 0xBA88B743);
@@ -912,6 +928,8 @@ test "xxhash32 smhasher" {
 }
 
 test "xxhash32 iterative api" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Test = struct {
         fn do() !void {
             try verify.iterativeApi(XxHash32);

lib/std/hash_map.zig

@@ -1873,6 +1873,8 @@ test "std.hash_map multiple removes on same metadata" {
 }
 
 test "std.hash_map put and remove loop in random order" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var map = AutoHashMap(u32, u32).init(std.testing.allocator);
     defer map.deinit();
 

lib/std/heap/general_purpose_allocator.zig

@@ -1042,6 +1042,8 @@ const TraceKind = enum {
 const test_config = Config{};
 
 test "small allocations - free in same order" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var gpa = GeneralPurposeAllocator(test_config){};
     defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
     const allocator = gpa.allocator();
@@ -1061,6 +1063,8 @@ test "small allocations - free in same order" {
 }
 
 test "small allocations - free in reverse order" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var gpa = GeneralPurposeAllocator(test_config){};
     defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
     const allocator = gpa.allocator();

lib/std/http/Client.zig

@@ -1,6 +1,7 @@
 //! Connecting and opening requests are threadsafe. Individual requests are not.
 
 const std = @import("../std.zig");
+const builtin = @import("builtin");
 const testing = std.testing;
 const http = std.http;
 const mem = std.mem;
@@ -427,6 +428,8 @@ pub const Response = struct {
     }
 
     test parseInt3 {
+        if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
         const expectEqual = testing.expectEqual;
         try expectEqual(@as(u10, 0), parseInt3("000".*));
         try expectEqual(@as(u10, 418), parseInt3("418".*));
@@ -585,7 +588,7 @@ pub const Request = struct {
 
         if (!req.headers.contains("user-agent")) {
             try w.writeAll("User-Agent: zig/");
-            try w.writeAll(@import("builtin").zig_version_string);
+            try w.writeAll(builtin.zig_version_string);
             try w.writeAll(" (std.http)\r\n");
         }
 
@@ -1249,7 +1252,6 @@ pub fn fetch(client: *Client, allocator: Allocator, options: FetchOptions) !Fetc
 }
 
 test {
-    const builtin = @import("builtin");
     const native_endian = comptime builtin.cpu.arch.endian();
     if (builtin.zig_backend == .stage2_llvm and native_endian == .Big) {
         // https://github.com/ziglang/zig/issues/13782
@@ -1258,5 +1260,7 @@ test {
 
     if (builtin.os.tag == .wasi) return error.SkipZigTest;
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     std.testing.refAllDecls(@This());
 }

lib/std/http/Server.zig

@@ -725,6 +725,8 @@ test "HTTP server handles a chunked transfer coding request" {
         return error.SkipZigTest;
     }
 
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const native_endian = comptime builtin.cpu.arch.endian();
     if (builtin.zig_backend == .stage2_llvm and native_endian == .Big) {
         // https://github.com/ziglang/zig/issues/13782

lib/std/io/bit_reader.zig

@@ -164,6 +164,8 @@ pub fn bitReader(
 }
 
 test "api coverage" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const mem_be = [_]u8{ 0b11001101, 0b00001011 };
     const mem_le = [_]u8{ 0b00011101, 0b10010101 };
 

lib/std/io/multi_writer.zig

@@ -36,6 +36,7 @@ pub fn multiWriter(streams: anytype) MultiWriter(@TypeOf(streams)) {
 const testing = std.testing;
 
 test "MultiWriter" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
     var tmp = testing.tmpDir(.{});
     defer tmp.cleanup();
     var f = try tmp.dir.createFile("t.txt", .{});

lib/std/io/test.zig

@@ -15,6 +15,8 @@ const native_endian = builtin.target.cpu.arch.endian();
 const tmpDir = std.testing.tmpDir;
 
 test "write a file, read it, then delete it" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -61,6 +63,8 @@ test "write a file, read it, then delete it" {
 }
 
 test "BitStreams with File Stream" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -106,6 +110,8 @@ test "BitStreams with File Stream" {
 }
 
 test "File seek ops" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -133,6 +139,8 @@ test "File seek ops" {
 }
 
 test "setEndPos" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 
@@ -159,6 +167,8 @@ test "setEndPos" {
 }
 
 test "updateTimes" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
 

lib/std/json.zig

@@ -9,6 +9,7 @@
 //! The low-level `writeStream` emits syntax-conformant JSON tokens to a `std.io.Writer`.
 //! The high-level `stringify` serializes a Zig or `Value` type into JSON.
 
+const builtin = @import("builtin");
 const testing = @import("std").testing;
 const ArrayList = @import("std").ArrayList;
 
@@ -23,6 +24,8 @@ test Scanner {
 }
 
 test parseFromSlice {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var parsed_str = try parseFromSlice([]const u8, testing.allocator, "\"a\\u0020b\"", .{});
     defer parsed_str.deinit();
     try testing.expectEqualSlices(u8, "a b", parsed_str.value);
@@ -35,12 +38,16 @@ test parseFromSlice {
 }
 
 test Value {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var parsed = try parseFromSlice(Value, testing.allocator, "{\"anything\": \"goes\"}", .{});
     defer parsed.deinit();
     try testing.expectEqualSlices(u8, "goes", parsed.value.object.get("anything").?.string);
 }
 
 test writeStream {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var out = ArrayList(u8).init(testing.allocator);
     defer out.deinit();
     var write_stream = writeStream(out.writer(), .{ .whitespace = .indent_2 });
@@ -58,6 +65,8 @@ test writeStream {
 }
 
 test stringify {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var out = ArrayList(u8).init(testing.allocator);
     defer out.deinit();
 

lib/std/json/JSONTestSuite_test.zig

@@ -104,6 +104,8 @@ test "i_string_utf16LE_no_BOM.json" {
     try any("[\x00\"\x00\xe9\x00\"\x00]\x00");
 }
 test "i_structure_500_nested_arrays.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try any("[" ** 500 ++ "]" ** 500);
 }
 test "i_structure_UTF-8_BOM_empty_object.json" {
@@ -359,15 +361,21 @@ test "n_object_bracket_key.json" {
     try err("{[: \"x\"}\n");
 }
 test "n_object_comma_instead_of_colon.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"x\", null}");
 }
 test "n_object_double_colon.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"x\"::\"b\"}");
 }
 test "n_object_emoji.json" {
     try err("{\xf0\x9f\x87\xa8\xf0\x9f\x87\xad}");
 }
 test "n_object_garbage_at_end.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"a\" 123}");
 }
 test "n_object_key_with_single_quotes.json" {
@@ -377,18 +385,26 @@ test "n_object_lone_continuation_byte_in_key_and_trailing_comma.json" {
     try err("{\"\xb9\":\"0\",}");
 }
 test "n_object_missing_colon.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\" b}");
 }
 test "n_object_missing_key.json" {
     try err("{:\"b\"}");
 }
 test "n_object_missing_semicolon.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\" \"b\"}");
 }
 test "n_object_missing_value.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":");
 }
 test "n_object_no-colon.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\"");
 }
 test "n_object_non_string_key.json" {
@@ -401,39 +417,59 @@ test "n_object_repeated_null_null.json" {
     try err("{null:null,null:null}");
 }
 test "n_object_several_trailing_commas.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"id\":0,,,,,}");
 }
 test "n_object_single_quote.json" {
     try err("{'a':0}");
 }
 test "n_object_trailing_comma.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"id\":0,}");
 }
 test "n_object_trailing_comment.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}/**/");
 }
 test "n_object_trailing_comment_open.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}/**//");
 }
 test "n_object_trailing_comment_slash_open.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}//");
 }
 test "n_object_trailing_comment_slash_open_incomplete.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}/");
 }
 test "n_object_two_commas_in_a_row.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\",,\"c\":\"d\"}");
 }
 test "n_object_unquoted_key.json" {
     try err("{a: \"b\"}");
 }
 test "n_object_unterminated-value.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"a");
 }
 test "n_object_with_single_string.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{ \"foo\" : \"bar\", \"a\" }");
 }
 test "n_object_with_trailing_garbage.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}#");
 }
 test "n_single_space.json" {
@@ -560,6 +596,8 @@ test "n_structure_close_unopened_array.json" {
     try err("1]");
 }
 test "n_structure_comma_instead_of_closing_brace.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"x\": true,");
 }
 test "n_structure_double_array.json" {
@@ -590,12 +628,18 @@ test "n_structure_object_followed_by_closing_object.json" {
     try err("{}}");
 }
 test "n_structure_object_unclosed_no_value.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"\":");
 }
 test "n_structure_object_with_comment.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":/*comment*/\"b\"}");
 }
 test "n_structure_object_with_trailing_garbage.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\": true} \"x\"");
 }
 test "n_structure_open_array_apostrophe.json" {
@@ -605,6 +649,8 @@ test "n_structure_open_array_comma.json" {
     try err("[,");
 }
 test "n_structure_open_array_object.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("[{\"\":" ** 50000 ++ "\n");
 }
 test "n_structure_open_array_open_object.json" {
@@ -644,6 +690,8 @@ test "n_structure_single_star.json" {
     try err("*");
 }
 test "n_structure_trailing_#.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"a\":\"b\"}#{}");
 }
 test "n_structure_uescaped_LF_before_string.json" {
@@ -662,6 +710,8 @@ test "n_structure_unclosed_array_unfinished_true.json" {
     try err("[ false, tru");
 }
 test "n_structure_unclosed_object.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err("{\"asd\":\"asd\"");
 }
 test "n_structure_unicode-identifier.json" {
@@ -764,39 +814,61 @@ test "y_number_simple_real.json" {
     try ok("[123.456789]");
 }
 test "y_object.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"asd\":\"sdf\", \"dfg\":\"fgh\"}");
 }
 test "y_object_basic.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"asd\":\"sdf\"}");
 }
 test "y_object_duplicated_key.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"a\":\"b\",\"a\":\"c\"}");
 }
 test "y_object_duplicated_key_and_value.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"a\":\"b\",\"a\":\"b\"}");
 }
 test "y_object_empty.json" {
     try ok("{}");
 }
 test "y_object_empty_key.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"\":0}");
 }
 test "y_object_escaped_null_in_key.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"foo\\u0000bar\": 42}");
 }
 test "y_object_extreme_numbers.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{ \"min\": -1.0e+28, \"max\": 1.0e+28 }");
 }
 test "y_object_long_strings.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"x\":[{\"id\": \"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\"}], \"id\": \"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\"}");
 }
 test "y_object_simple.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"a\":[]}");
 }
 test "y_object_string_unicode.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\"title\":\"\\u041f\\u043e\\u043b\\u0442\\u043e\\u0440\\u0430 \\u0417\\u0435\\u043c\\u043b\\u0435\\u043a\\u043e\\u043f\\u0430\" }");
 }
 test "y_object_with_newlines.json" {
+    if (@import("builtin").zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try ok("{\n\"a\": \"b\"\n}");
 }
 test "y_string_1_2_3_bytes_UTF-8_sequences.json" {

lib/std/json/dynamic_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const mem = std.mem;
 const testing = std.testing;
 const ArenaAllocator = std.heap.ArenaAllocator;
@@ -18,6 +19,8 @@ const jsonReader = @import("scanner.zig").reader;
 const JsonReader = @import("scanner.zig").Reader;
 
 test "json.parser.dynamic" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const s =
         \\{
         \\  "Image": {
@@ -72,6 +75,8 @@ test "json.parser.dynamic" {
 
 const writeStream = @import("./stringify.zig").writeStream;
 test "write json then parse it" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var out_buffer: [1000]u8 = undefined;
 
     var fixed_buffer_stream = std.io.fixedBufferStream(&out_buffer);
@@ -120,12 +125,16 @@ fn testParse(allocator: std.mem.Allocator, json_str: []const u8) !Value {
 }
 
 test "parsing empty string gives appropriate error" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena_allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena_allocator.deinit();
     try testing.expectError(error.UnexpectedEndOfInput, testParse(arena_allocator.allocator(), ""));
 }
 
 test "Value.array allocator should still be usable after parsing" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var parsed = try parseFromSlice(Value, std.testing.allocator, "[]", .{});
     defer parsed.deinit();
 
@@ -138,6 +147,8 @@ test "Value.array allocator should still be usable after parsing" {
 }
 
 test "integer after float has proper type" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena_allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena_allocator.deinit();
     const parsed = try testParse(arena_allocator.allocator(),
@@ -150,6 +161,8 @@ test "integer after float has proper type" {
 }
 
 test "escaped characters" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena_allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena_allocator.deinit();
     const input =
@@ -182,6 +195,8 @@ test "escaped characters" {
 }
 
 test "Value.jsonStringify" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var vals = [_]Value{
         .{ .integer = 1 },
         .{ .integer = 2 },
@@ -229,6 +244,8 @@ test "Value.jsonStringify" {
 }
 
 test "parseFromValue(std.json.Value,...)" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const str =
         \\{
         \\  "int": 32,
@@ -246,6 +263,8 @@ test "parseFromValue(std.json.Value,...)" {
 }
 
 test "polymorphic parsing" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     if (true) return error.SkipZigTest; // See https://github.com/ziglang/zig/issues/16108
     const doc =
         \\{ "type": "div",
@@ -291,6 +310,8 @@ test "polymorphic parsing" {
 }
 
 test "long object value" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const value = "01234567890123456789";
     const doc = "{\"key\":\"" ++ value ++ "\"}";
     var fbs = std.io.fixedBufferStream(doc);
@@ -303,6 +324,8 @@ test "long object value" {
 }
 
 test "ParseOptions.max_value_len" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena = ArenaAllocator.init(testing.allocator);
     defer arena.deinit();
 
@@ -317,6 +340,8 @@ test "ParseOptions.max_value_len" {
 }
 
 test "many object keys" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const doc =
         \\{
         \\  "k1": "v1",

lib/std/json/hashmap_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const testing = std.testing;
 
 const ArrayHashMap = @import("hashmap.zig").ArrayHashMap;
@@ -18,6 +19,8 @@ const T = struct {
 };
 
 test "parse json hashmap" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const doc =
         \\{
         \\  "abc": {"i": 0, "s": "d"},
@@ -33,6 +36,8 @@ test "parse json hashmap" {
 }
 
 test "parse json hashmap while streaming" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const doc =
         \\{
         \\  "abc": {"i": 0, "s": "d"},
@@ -58,6 +63,8 @@ test "parse json hashmap while streaming" {
 }
 
 test "parse json hashmap duplicate fields" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena.deinit();
 
@@ -86,6 +93,8 @@ test "parse json hashmap duplicate fields" {
 }
 
 test "stringify json hashmap" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var value = ArrayHashMap(T){};
     defer value.deinit(testing.allocator);
     {
@@ -123,6 +132,8 @@ test "stringify json hashmap" {
 }
 
 test "stringify json hashmap whitespace" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var value = ArrayHashMap(T){};
     defer value.deinit(testing.allocator);
     try value.map.put(testing.allocator, "abc", .{ .i = 0, .s = "d" });
@@ -147,6 +158,8 @@ test "stringify json hashmap whitespace" {
 }
 
 test "json parse from value hashmap" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const doc =
         \\{
         \\  "abc": {"i": 0, "s": "d"},

lib/std/json/static_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const testing = std.testing;
 const ArenaAllocator = std.heap.ArenaAllocator;
 const Allocator = std.mem.Allocator;
@@ -371,6 +372,8 @@ test "test all types" {
 }
 
 test "parse" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectEqual(false, try parseFromSliceLeaky(bool, testing.allocator, "false", .{}));
     try testing.expectEqual(true, try parseFromSliceLeaky(bool, testing.allocator, "true", .{}));
     try testing.expectEqual(@as(u1, 1), try parseFromSliceLeaky(u1, testing.allocator, "1", .{}));
@@ -389,6 +392,8 @@ test "parse" {
 }
 
 test "parse into enum" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = enum(u32) {
         Foo = 42,
         Bar,
@@ -402,6 +407,8 @@ test "parse into enum" {
 }
 
 test "parse into that allocates a slice" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         // string as string
         const parsed = try parseFromSlice([]u8, testing.allocator, "\"foo\"", .{});
@@ -422,12 +429,16 @@ test "parse into that allocates a slice" {
 }
 
 test "parse into sentinel slice" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const parsed = try parseFromSlice([:0]const u8, testing.allocator, "\"\\n\"", .{});
     defer parsed.deinit();
     try testing.expect(std.mem.eql(u8, parsed.value, "\n"));
 }
 
 test "parse into tagged union" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = union(enum) {
         nothing,
         int: i32,
@@ -443,6 +454,8 @@ test "parse into tagged union" {
 }
 
 test "parse into tagged union errors" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = union(enum) {
         nothing,
         int: i32,
@@ -465,6 +478,8 @@ test "parse into tagged union errors" {
 }
 
 test "parse into struct with no fields" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {};
     const parsed = try parseFromSlice(T, testing.allocator, "{}", .{});
     defer parsed.deinit();
@@ -474,6 +489,8 @@ test "parse into struct with no fields" {
 const test_const_value: usize = 123;
 
 test "parse into struct with default const pointer field" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct { a: *const usize = &test_const_value };
     const parsed = try parseFromSlice(T, testing.allocator, "{}", .{});
     defer parsed.deinit();
@@ -489,6 +506,8 @@ const test_default_str_slice: [2][]const u8 = [_][]const u8{
 };
 
 test "freeing parsed structs with pointers to default values" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         int: *const usize = &test_default_usize,
         int_ptr: *allowzero align(1) const usize = test_default_usize_ptr,
@@ -502,11 +521,15 @@ test "freeing parsed structs with pointers to default values" {
 }
 
 test "parse into struct where destination and source lengths mismatch" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct { a: [2]u8 };
     try testing.expectError(error.LengthMismatch, parseFromSlice(T, testing.allocator, "{\"a\": \"bbb\"}", .{}));
 }
 
 test "parse into struct with misc fields" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         int: i64,
         float: f64,
@@ -582,6 +605,8 @@ test "parse into struct with misc fields" {
 }
 
 test "parse into struct with strings and arrays with sentinels" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         language: [:0]const u8,
         language_without_sentinel: []const u8,
@@ -610,6 +635,8 @@ test "parse into struct with strings and arrays with sentinels" {
 }
 
 test "parse into struct with duplicate field" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const options_first = ParseOptions{ .duplicate_field_behavior = .use_first };
     const options_last = ParseOptions{ .duplicate_field_behavior = .use_last };
 
@@ -629,6 +656,8 @@ test "parse into struct with duplicate field" {
 }
 
 test "parse into struct ignoring unknown fields" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         int: i64,
         language: []const u8,
@@ -667,6 +696,8 @@ test "parse into struct ignoring unknown fields" {
 }
 
 test "parse into tuple" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Union = union(enum) {
         char: u8,
         float: f64,
@@ -722,6 +753,8 @@ const ParseIntoRecursiveUnionDefinitionValue = union(enum) {
 };
 
 test "parse into recursive union definition" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         values: ParseIntoRecursiveUnionDefinitionValue,
     };
@@ -743,6 +776,8 @@ const ParseIntoDoubleRecursiveUnionValueSecond = union(enum) {
 };
 
 test "parse into double recursive union definition" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         values: ParseIntoDoubleRecursiveUnionValueFirst,
     };
@@ -754,6 +789,8 @@ test "parse into double recursive union definition" {
 }
 
 test "parse exponential into int" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct { int: i64 };
     const r = try parseFromSliceLeaky(T, testing.allocator, "{ \"int\": 4.2e2 }", .{});
     try testing.expectEqual(@as(i64, 420), r.int);
@@ -762,6 +799,8 @@ test "parse exponential into int" {
 }
 
 test "parseFromTokenSource" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     {
         var scanner = JsonScanner.initCompleteInput(testing.allocator, "123");
         defer scanner.deinit();
@@ -781,10 +820,14 @@ test "parseFromTokenSource" {
 }
 
 test "max_value_len" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testing.expectError(error.ValueTooLong, parseFromSlice([]u8, testing.allocator, "\"0123456789\"", .{ .max_value_len = 5 }));
 }
 
 test "parse into vector" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         vec_i32: @Vector(4, i32),
         vec_f32: @Vector(2, f32),
@@ -817,6 +860,8 @@ fn assertKey(
     }
 }
 test "json parse partial" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const Inner = struct {
         num: u32,
         yes: bool,
@@ -872,6 +917,8 @@ test "json parse partial" {
 }
 
 test "json parse allocate when streaming" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = struct {
         not_const: []u8,
         is_const: []const u8,
@@ -902,6 +949,8 @@ test "json parse allocate when streaming" {
 }
 
 test "parse at comptime" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const doc =
         \\{
         \\    "vals": {

lib/std/json/stringify_test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const mem = std.mem;
 const testing = std.testing;
 
@@ -15,6 +16,8 @@ const writeStreamMaxDepth = @import("stringify.zig").writeStreamMaxDepth;
 const writeStreamArbitraryDepth = @import("stringify.zig").writeStreamArbitraryDepth;
 
 test "json write stream" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var out_buf: [1024]u8 = undefined;
     var slice_stream = std.io.fixedBufferStream(&out_buf);
     const out = slice_stream.writer();
@@ -97,6 +100,8 @@ fn getJsonObject(allocator: std.mem.Allocator) !Value {
 }
 
 test "stringify null optional fields" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const MyStruct = struct {
         optional: ?[]const u8 = null,
         required: []const u8 = "something",
@@ -118,6 +123,8 @@ test "stringify null optional fields" {
 }
 
 test "stringify basic types" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("false", false, .{});
     try testStringify("true", true, .{});
     try testStringify("null", @as(?u8, null), .{});
@@ -134,6 +141,8 @@ test "stringify basic types" {
 }
 
 test "stringify string" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("\"hello\"", "hello", .{});
     try testStringify("\"with\\nescapes\\r\"", "with\nescapes\r", .{});
     try testStringify("\"with\\nescapes\\r\"", "with\nescapes\r", .{ .escape_unicode = true });
@@ -158,12 +167,16 @@ test "stringify string" {
 }
 
 test "stringify many-item sentinel-terminated string" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("\"hello\"", @as([*:0]const u8, "hello"), .{});
     try testStringify("\"with\\nescapes\\r\"", @as([*:0]const u8, "with\nescapes\r"), .{ .escape_unicode = true });
     try testStringify("\"with unicode\\u0001\"", @as([*:0]const u8, "with unicode\u{1}"), .{ .escape_unicode = true });
 }
 
 test "stringify enums" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const E = enum {
         foo,
         bar,
@@ -173,11 +186,15 @@ test "stringify enums" {
 }
 
 test "stringify enum literals" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("\"foo\"", .foo, .{});
     try testStringify("\"bar\"", .bar, .{});
 }
 
 test "stringify tagged unions" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const T = union(enum) {
         nothing,
         foo: u32,
@@ -189,12 +206,16 @@ test "stringify tagged unions" {
 }
 
 test "stringify struct" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("{\"foo\":42}", struct {
         foo: u32,
     }{ .foo = 42 }, .{});
 }
 
 test "emit_strings_as_arrays" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Should only affect string values, not object keys.
     try testStringify("{\"foo\":\"bar\"}", .{ .foo = "bar" }, .{});
     try testStringify("{\"foo\":[98,97,114]}", .{ .foo = "bar" }, .{ .emit_strings_as_arrays = true });
@@ -209,6 +230,8 @@ test "emit_strings_as_arrays" {
 }
 
 test "stringify struct with indentation" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify(
         \\{
         \\    "foo": 42,
@@ -254,6 +277,8 @@ test "stringify struct with indentation" {
 }
 
 test "stringify struct with void field" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("{\"foo\":42}", struct {
         foo: u32,
         bar: void = {},
@@ -261,6 +286,8 @@ test "stringify struct with void field" {
 }
 
 test "stringify array of structs" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const MyStruct = struct {
         foo: u32,
     };
@@ -272,6 +299,8 @@ test "stringify array of structs" {
 }
 
 test "stringify struct with custom stringifier" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("[\"something special\",42]", struct {
         foo: u32,
         const Self = @This();
@@ -286,12 +315,16 @@ test "stringify struct with custom stringifier" {
 }
 
 test "stringify vector" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("[1,1]", @as(@Vector(2, u32), @splat(1)), .{});
     try testStringify("\"AA\"", @as(@Vector(2, u8), @splat('A')), .{});
     try testStringify("[65,65]", @as(@Vector(2, u8), @splat('A')), .{ .emit_strings_as_arrays = true });
 }
 
 test "stringify tuple" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("[\"foo\",42]", std.meta.Tuple(&.{ []const u8, usize }){ "foo", 42 }, .{});
 }
 
@@ -378,6 +411,8 @@ fn testStringifyArbitraryDepth(expected: []const u8, value: anytype, options: St
 }
 
 test "stringify alloc" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     const allocator = std.testing.allocator;
     const expected =
         \\{"foo":"bar","answer":42,"my_friend":"sammy"}
@@ -389,6 +424,8 @@ test "stringify alloc" {
 }
 
 test "comptime stringify" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     comptime testStringifyMaxDepth("false", false, .{}, null) catch unreachable;
     comptime testStringifyMaxDepth("false", false, .{}, 0) catch unreachable;
     comptime testStringifyArbitraryDepth("false", false, .{}) catch unreachable;
@@ -409,6 +446,8 @@ test "comptime stringify" {
 }
 
 test "print" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     var out_buf: [1024]u8 = undefined;
     var slice_stream = std.io.fixedBufferStream(&out_buf);
     const out = slice_stream.writer();
@@ -440,6 +479,8 @@ test "print" {
 }
 
 test "nonportable numbers" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try testStringify("9999999999999999", 9999999999999999, .{});
     try testStringify("\"9999999999999999\"", 9999999999999999, .{ .emit_nonportable_numbers_as_strings = true });
 }

lib/std/json/test.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const testing = std.testing;
 const parseFromSlice = @import("./static.zig").parseFromSlice;
 const validate = @import("./scanner.zig").validate;
@@ -34,11 +35,15 @@ fn testHighLevelDynamicParser(s: []const u8) !void {
 
 // Additional tests not part of test JSONTestSuite.
 test "y_trailing_comma_after_empty" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try roundTrip(
         \\{"1":[],"2":{},"3":"4"}
     );
 }
 test "n_object_closed_missing_value" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     try err(
         \\{"a":}
     );

lib/std/leb128.zig

@@ -215,6 +215,8 @@ fn test_read_uleb128_seq(comptime T: type, comptime N: usize, encoded: []const u
 }
 
 test "deserialize signed LEB128" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // Truncated
     try testing.expectError(error.EndOfStream, test_read_stream_ileb128(i64, "\x80"));
 
@@ -361,6 +363,8 @@ test "serialize unsigned LEB128" {
 }
 
 test "serialize signed LEB128" {
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+
     // explicitly test i0 because starting `t` at 0
     // will break the while loop
     try test_write_leb128(@as(i0, 0));