[Bug c/25371] New: -ftree-vectorize results in internal compiler error on AMD64

[David dot Monniaux at ens dot fr]

Same problem occurs in 4.0.1, 4.1 (Subversion) but not in 4.2 (Subversion).

$ gcc -c -ftree-vectorize -O2 oct_makes_gcc_explode.i
oct_makes_gcc_explode.i: In function ‘slow_close’:
oct_makes_gcc_explode.i:8: internal compiler error: in gimplify_expr, at
gimplify.c:4182

$ cat oct_makes_gcc_explode.i
typedef double num_t;
typedef long size_t;
void *octfag_mm_malloc (size_t t);
void octfag_mm_free (void* p);

void
slow_close(num_t* m, int n)
{
  int i,j,k;
  num_t* mm = ((num_t*) octfag_mm_malloc (sizeof(num_t)*(4*n*n)));
  num_t a,b,c,d;
  ;
  ; ; ; ;
  for (k=0;k<2*n;k+=2) {
    for (i=0;i<2*n;i++)
      for (j=0;j<2*n;j++) {
 *(&a) = *(m+i*2*n+k) + *(m+k*2*n+j);
 *(&b) = *(m+i*2*n+k+1) + *(m+(k+1)*2*n+j);
 *(&c) = *(m+i*2*n+k) + *(m+k*2*n+k+1); *(&c) = *(&c) + *(m+(k+1)*2*n+j);
 *(&d) = *(m+i*2*n+k+1) + *(m+(k+1)*2*n+k); *(&d) = *(&d) + *(m+k*2*n+j);
 num_min(&a,&a,&b);
 num_min(&c,&c,&d);
 num_min(&a,&a,&c);
 num_min(mm+i*2*n+j,mm+i*2*n+j,&a);
      }
    for (i=0;i<2*n;i++) *(mm+i*2*n+i) = (num_t)(0);
    for (i=0;i<2*n;i++)
      for (j=0;j<2*n;j++) {
 *(&a) = *(mm+i*2*n+(i^1)) / 2.;
 *(&b) = *(mm+(j^1)*2*n+j) / 2.;
 *(&a) = *(&a) + *(&b);
 num_min(mm+i*2*n+j,mm+i*2*n+j,&a);
      }
  }
  ;
  ; ; ; ;
  octfag_mm_free(mm);
}


-- 
           Summary: -ftree-vectorize results in internal compiler error on
                    AMD64
           Product: gcc
           Version: 4.0.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: David dot Monniaux at ens dot fr
 GCC build triplet: x86_64-redhat-linux
  GCC host triplet: x86_64-redhat-linux
GCC target triplet: x86_64-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25371