Messages in this thread Patch in this message | | | Date | Thu, 27 May 2010 20:12:54 GMT | From | "tip-bot for H. Peter Anvin" <> | Subject | [tip:x86/urgent] x86, cpufeature: Unbreak compile with gcc 3.x |
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Commit-ID: 1ba4f22c426ba04b00fd717318d50620c621a0e1 Gitweb: http://git.kernel.org/tip/1ba4f22c426ba04b00fd717318d50620c621a0e1 Author: H. Peter Anvin <hpa@linux.intel.com> AuthorDate: Thu, 27 May 2010 12:02:00 -0700 Committer: H. Peter Anvin <hpa@linux.intel.com> CommitDate: Thu, 27 May 2010 12:02:00 -0700
x86, cpufeature: Unbreak compile with gcc 3.x
gcc 3 is too braindamaged to be able to compile static_cpu_has() -- apparently it can't tell that a constant passed to an inline function is still a constant -- so if we're using gcc 3, just use the dynamic test. This is bad for performance, but if you care about performance, don't use an ancient, known-to-optimize-poorly compiler.
Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com> LKML-Reference: <4BF2FF82.7090005@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> --- arch/x86/include/asm/cpufeature.h | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index dca9c54..4681459 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -332,6 +332,7 @@ static __always_inline __pure bool __static_cpu_has(u8 bit) #endif } +#if __GNUC__ >= 4 #define static_cpu_has(bit) \ ( \ __builtin_constant_p(boot_cpu_has(bit)) ? \ @@ -340,6 +341,12 @@ static __always_inline __pure bool __static_cpu_has(u8 bit) __static_cpu_has(bit) : \ boot_cpu_has(bit) \ ) +#else +/* + * gcc 3.x is too stupid to do the static test; fall back to dynamic. + */ +#define static_cpu_has(bit) boot_cpu_has(bit) +#endif #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
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