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On Oct 25, 2012, at 6:13 PM, Eli Friedman <[email protected]> wrote: > On Thu, Oct 25, 2012 at 5:25 PM, Manman Ren <[email protected]> wrote: >> Author: mren >> Date: Thu Oct 25 19:25:10 2012 >> New Revision: 166743 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=166743&view=rev >> Log: >> X86 SSE Intrinsics: update header for sqrt_ss, rsqrt_ss and rcp_ss. >> >> There intrinsics pass through the upper FP values from the input. >> rdar://12558838 >> >> Modified: >> cfe/trunk/lib/Headers/xmmintrin.h >> cfe/trunk/test/CodeGen/sse-builtins.c >> >> Modified: cfe/trunk/lib/Headers/xmmintrin.h >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/xmmintrin.h?rev=166743&r1=166742&r2=166743&view=diff >> ============================================================================== >> --- cfe/trunk/lib/Headers/xmmintrin.h (original) >> +++ cfe/trunk/lib/Headers/xmmintrin.h Thu Oct 25 19:25:10 2012 >> @@ -95,7 +95,8 @@ >> static __inline__ __m128 __attribute__((__always_inline__, __nodebug__)) >> _mm_sqrt_ss(__m128 a) >> { >> - return __builtin_ia32_sqrtss(a); >> + __m128 c = __builtin_ia32_sqrtss(a); >> + return (__m128) { c[0], a[1], a[2], a[3] }; >> } > > What does exactly does __builtin_ia32_sqrtss return, if not the result > of a sqrtss instruction? builtin returns the result of sqrtss instruction, which only updates the lowest FP. mm_sqrt_ss has the upper FPs pass through to the output. Thanks Manman > > -Eli _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
