[Bug tree-optimization/66580] New: max reduction does not auto vectorize

[dejan.crnila at dewesoft dot si]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66580

            Bug ID: 66580
           Summary: max reduction does not auto vectorize
           Product: gcc
           Version: 5.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dejan.crnila at dewesoft dot si
  Target Milestone: ---

following code does (max reduction) not auto vectorize on x64/mingw gcc

#include <stdio.h>
#include <float.h>

int main()
{
        float a[] __attribute__((aligned(0x20))) = {0, 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16};
        float maxval = -FLT_MAX;        
        for (size_t i = 0; i < 16; i++)
                maxval = a[i] > maxval ? a[i] : maxval;

        printf("%g\n", maxval);
}

compiled as 

gcc test.c -O3 -Wall -o test.exe -ftree-vectorizer-verbose=6 
-fopt-info-vec-all -ffast-math -mavx

not supported or bug?