[Bug c/88153] New: sqrt() is not vectorized

[bugzilla@poradnik-webmastera.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88153

            Bug ID: 88153
           Summary: sqrt() is not vectorized
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bugzilla@poradnik-webmastera.com
  Target Milestone: ---

Sequence of calls to sqrt() is not vectorized.

I found Bug 21466 that claims that it was fixed in GCC 4.3, but looks that
change was reverted - at least 4.4.7 it also is not vectorized. I suspect that
after that change errors were not reported correctly - non-vectorized code uses
sqrtsd, and for negative numbers it also calls sqrt for its side effects.

I wrote following code snippet as a possible solution for SSE instructions. I
did not check all details how errors should be reported for sequence of sqrt
calls, so it may need some changes.

#include <emmintrin.h>
#include <math.h>

#define SIZE 8
double d1[SIZE];
double d2[SIZE];

void test()
{
    int m = 0;
    for (int n = 0; n < SIZE; n += 2)
    {
        __m128d v = _mm_load_pd(&d1[n]);
        __m128d vs = _mm_sqrt_pd(v);
        __m128d vn = _mm_cmplt_pd(v, _mm_setzero_pd());
        m |= _mm_movemask_pd(vn);
        _mm_store_pd(&d2[n], vs);
    }

    if (m)
        sqrt(-1.0);
}