diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index e9aa4e8b07dd..5f16ac1583c5 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -245,7 +245,9 @@ cpu-as-$(CONFIG_E500)		+= -Wa,-me500
 # When using '-many -mpower4' gas will first try and find a matching power4
 # mnemonic and failing that it will allow any valid mnemonic that GAS knows
 # about. GCC will pass -many to GAS when assembling, clang does not.
-cpu-as-$(CONFIG_PPC_BOOK3S_64)	+= -Wa,-mpower4 -Wa,-many
+# LLVM IAS doesn't understand either flag: https://github.com/ClangBuiltLinux/linux/issues/675
+# but LLVM IAS only supports ISA >= 2.06 for Book3S 64 anyway...
+cpu-as-$(CONFIG_PPC_BOOK3S_64)	+= $(call as-option,-Wa$(comma)-mpower4) $(call as-option,-Wa$(comma)-many)
 cpu-as-$(CONFIG_PPC_E500MC)	+= $(call as-option,-Wa$(comma)-me500mc)
 
 KBUILD_AFLAGS += $(cpu-as-y)