Commit 1ba4f22c authored May 27, 2010 by H. Peter Anvin

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>

parent 20413f27

arch/x86/include/asm/cpufeature.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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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