forked from Minki/linux
de9c0d49d8
While building arm32 allyesconfig, I ran into the following errors:
arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with
'-mfloat-abi=softfp -mfpu=neon'
In file included from lib/raid6/neon1.c:27:
/home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2:
error: "NEON support not enabled"
Building V=1 showed NEON_FLAGS getting passed along to Clang but
__ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang
only defining __ARM_NEON__ when targeting armv7, rather than armv6k,
which is the '-march' value for allyesconfig.
>From lib/Basic/Targets/ARM.cpp in the Clang source:
// This only gets set when Neon instructions are actually available, unlike
// the VFP define, hence the soft float and arch check. This is subtly
// different from gcc, we follow the intent which was that it should be set
// when Neon instructions are actually available.
if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) {
Builder.defineMacro("__ARM_NEON", "1");
Builder.defineMacro("__ARM_NEON__");
// current AArch32 NEON implementations do not support double-precision
// floating-point even when it is present in VFP.
Builder.defineMacro("__ARM_NEON_FP",
"0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP));
}
Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the
beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets
definined by Clang. This doesn't functionally change anything because
that code will only run where NEON is supported, which is implicitly
armv7.
Link: https://github.com/ClangBuiltLinux/linux/issues/287
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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| .. | ||
| ashldi3.S | ||
| ashrdi3.S | ||
| backtrace.S | ||
| bitops.h | ||
| bswapsdi2.S | ||
| call_with_stack.S | ||
| changebit.S | ||
| clear_user.S | ||
| clearbit.S | ||
| copy_from_user.S | ||
| copy_page.S | ||
| copy_template.S | ||
| copy_to_user.S | ||
| csumipv6.S | ||
| csumpartial.S | ||
| csumpartialcopy.S | ||
| csumpartialcopygeneric.S | ||
| csumpartialcopyuser.S | ||
| delay-loop.S | ||
| delay.c | ||
| div64.S | ||
| ecard.S | ||
| findbit.S | ||
| floppydma.S | ||
| getuser.S | ||
| io-acorn.S | ||
| io-readsb.S | ||
| io-readsl.S | ||
| io-readsw-armv3.S | ||
| io-readsw-armv4.S | ||
| io-writesb.S | ||
| io-writesl.S | ||
| io-writesw-armv3.S | ||
| io-writesw-armv4.S | ||
| lib1funcs.S | ||
| lshrdi3.S | ||
| Makefile | ||
| memchr.S | ||
| memcpy.S | ||
| memmove.S | ||
| memset.S | ||
| muldi3.S | ||
| putuser.S | ||
| setbit.S | ||
| strchr.S | ||
| strrchr.S | ||
| testchangebit.S | ||
| testclearbit.S | ||
| testsetbit.S | ||
| uaccess_with_memcpy.c | ||
| ucmpdi2.S | ||
| xor-neon.c | ||