[Bug target/83479] Register spilling in AVX code

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83479

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
And compiling with -Wall gives

t.c: In function ‘test’:
t.c:32:37: warning: index value is out of bound [-Warray-bounds]
   vLastCol = _mm256_set1_pd(vLastRow[4]);
                                     ^
t.c:35:37: warning: index value is out of bound [-Warray-bounds]
   vLastCol = _mm256_set1_pd(vLastRow[5]);
                                     ^
t.c:38:37: warning: index value is out of bound [-Warray-bounds]
   vLastCol = _mm256_set1_pd(vLastRow[6]);
                                     ^
t.c:41:37: warning: index value is out of bound [-Warray-bounds]
   vLastCol = _mm256_set1_pd(vLastRow[7]);
                                     ^
t.c:61:37: warning: index value is out of bound [-Warray-bounds]
   vLastCol = _mm256_set1_pd(vLastRow[4]);
                                     ^
...