The fancy x86 hweight uses different compiler options for the hweight file. This does not work with LTO. Just disable the optimization with LTO v2: Simplify Kconfig checks (Jan Beulich) Cc: x86@xxxxxxxxxx Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/arch_hweight.h | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 940e50e..f125c5f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -255,6 +255,7 @@ config X86_32_LAZY_GS config ARCH_HWEIGHT_CFLAGS string + default "" if LTO default "-fcall-saved-ecx -fcall-saved-edx" if X86_32 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64 diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h index 9686c3d..ca80549 100644 --- a/arch/x86/include/asm/arch_hweight.h +++ b/arch/x86/include/asm/arch_hweight.h @@ -25,9 +25,14 @@ static inline unsigned int __arch_hweight32(unsigned int w) { unsigned int res = 0; +#ifdef CONFIG_LTO + res = __sw_hweight32(w); +#else + asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT) : "="REG_OUT (res) : REG_IN (w)); +#endif return res; } @@ -46,6 +51,9 @@ static inline unsigned long __arch_hweight64(__u64 w) { unsigned long res = 0; +#ifdef CONFIG_LTO + res = __sw_hweight64(w); +#else #ifdef CONFIG_X86_32 return __arch_hweight32((u32)w) + __arch_hweight32((u32)(w >> 32)); @@ -54,6 +62,7 @@ static inline unsigned long __arch_hweight64(__u64 w) : "="REG_OUT (res) : REG_IN (w)); #endif /* CONFIG_X86_32 */ +#endif return res; } -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html