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x86, cpufeature: Unbreak compile with gcc 3.x

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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>
This commit is contained in:
H. Peter Anvin 2010-05-27 12:02:00 -07:00
parent 20413f2716
commit 1ba4f22c42
1 changed files with 7 additions and 0 deletions
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7
arch/x86/include/asm/cpufeature.h
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@ -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__) */