[Bug middle-end/47895] New: usage of __attribute__ ((__target__ ("xyz"))) with buitins

["vincenzo.innocente at cern dot ch" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47895

           Summary: usage of __attribute__ ((__target__ ("xyz"))) with
                    buitins
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: vincenzo.innocente@cern.ch


I would like to generate code for multiple targets from the same source when
using builtins
(
I think that this issue has been discussed before for instance in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39840
) 


I have code as in the example below that compiles only with -mavx.
In such a case it will use AVX instruction for all functions including the one
"targetted" for sse3
while I would like to obtain an object file that I can run on multiple
platform.
This problem occurs only when builtins are used: standard c code is correctly
emitted accordingly to the target provided that the minimal -m is used.

Is there any preprocessor flag to "activate" all intrinsics and builtins in
x86intrin.h?

-----------------------------
example

#include <x86intrin.h>

float  __attribute__ ((__target__ ("sse3"))) sum3(float const * __restrict__ x,
float const * __restrict__ y, float const * __restrict__ z) {
  __m128 sum = _mm_setzero_ps();
  for (int i=0; i!=1024; i+=4)
    sum  += _mm_add_ps(_mm_loadu_ps(z+i),
                       _mm_mul_ps(_mm_loadu_ps(x+i),_mm_loadu_ps(y+i)) );
    sum = _mm_hadd_ps(sum,sum);
    sum = _mm_hadd_ps(sum,sum);
  float ret;
  _mm_store_ss(&ret,sum);
  return ret;
}

float  __attribute__ ((__target__ ("avx"))) sumv(float const * __restrict__ x,
float const * __restrict__ y, float const * __restrict__ z) {
  __m256 sum = _mm256_setzero_ps();
  for (int i=0; i!=1024; i+=8)
    sum  += _mm256_add_ps(_mm256_loadu_ps(z+i),
                       _mm256_mul_ps(_mm256_loadu_ps(x+i),_mm256_loadu_ps(y+i))
);
    sum = _mm256_hadd_ps(sum,sum);
    sum = _mm256_hadd_ps(sum,sum);
    sum = _mm256_hadd_ps(sum,sum);
  float ret[8];
  _mm256_store_ps(ret,sum);
  return ret[0];
}