[cfe-commits] r166743 - in /cfe/trunk: lib/Headers/xmmintrin.h test/CodeGen/sse-builtins.c

[Manman Ren]

Sent from my iPhone

On Oct 25, 2012, at 6:13 PM, Eli Friedman <eli.friedman at gmail.com> wrote:

> On Thu, Oct 25, 2012 at 5:25 PM, Manman Ren <mren at apple.com> 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