[Bug c/108191] New: Add support to usage of *intrin.h without -mavx512f -mavx512cd

[luoyonggang at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108191

            Bug ID: 108191
           Summary: Add support to usage of *intrin.h without -mavx512f
                    -mavx512cd
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: luoyonggang at gmail dot com
  Target Milestone: ---

This is for getting the following command to be works
```
gcc -fPIC -O2 -D__SSE3__=1 -D__SSSE3__=1 \
-D__SSE4_1__=1 -D__SSE4_2__=1 -D__SSE4A__=1 \
-D__POPCNT__=1 -D__XSAVE__=1 -D__CRC32__=1 \
-D__AVX__=1 -D__AVX2__=1 \
-D__FP_FAST_FMAF32=1 \
-D__FP_FAST_FMAF64=1 \
-D__FP_FAST_FMAF=1 \
-D__FP_FAST_FMAF32x=1 \
-D__AVX512F__=1 -D__AVX512CD__=1 test.c
```
That is generating code for SSE2 only, and we can using 
#include <x86intrin.h>
by using runtime flags.

Indeed, MSVC are aready can did that, if gcc can also support for that, we can
reduce the usage of inline assembly, because MSVC(x64) doesn't support for
inline assembly, so that we can reduce the code complex

The content of test.c is:
```
#if defined(_MSC_VER)
#include <intrin.h>
#else
#include <x86intrin.h>
#endif

#include <math.h>

static inline int
util_iround(float f)
{
   __m128 m = _mm_set_ss(f);
   return _mm_cvtss_i32(m);
}

int util_iround_outside(int x, float y) {
    return x + util_iround(y);
}
```

The compile error is something like:
```
In file included from
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/immintrin.h:35,
                 from
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/x86intrin.h:32,
                 from test.c:4:
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:
In function '_mm_addsub_ps':
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:53:3:
error: cannot convert a value of type 'int' to vector type '__vector(4) float'
which has different size
   53 |   return (__m128) __builtin_ia32_addsubps ((__v4sf)__X, (__v4sf)__Y);
      |   ^~~~~~
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:
In function '_mm_hadd_ps':
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:59:3:
error: cannot convert a value of type 'int' to vector type '__vector(4) float'
which has different size
   59 |   return (__m128) __builtin_ia32_haddps ((__v4sf)__X, (__v4sf)__Y);
      |   ^~~~~~
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:
In function '_mm_hsub_ps':
C:/CI-Tools/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/12.2.0/include/pmmintrin.h:65:3:
error: cannot convert a value of type 'int' to vector type '__vector(4) float'
which has different size
   65 |   return (__m128) __builtin_ia32_hsubps ((__v4sf)__X, (__v4sf)__Y);
```