https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66981
Bug ID: 66981
Summary: [graphite] delinearization of arrays
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: spop at gcc dot gnu.org
Reporter: spop at gcc dot gnu.org
CC: hiraditya at msn dot com
Target Milestone: ---
Graphite needs to delinearize the memory accesses in this loop to do
vectorization and parallelization:
$ cat s.c
void foo(unsigned char *in, unsigned char *out, int w, int h)
{
unsigned int i, j;
for (i = 0; i < 3*w*h; i++)
for (j = 0; j < 3*w*h; j++)
out[i*w+j] = in[(i*w+j)*3] + in[(i*w+j)*3+1] + in[(i*w+j)*3+2];
}
$ gcc -O3 -floop-parallelize-all s.c
Polly vectorizes this loop with vector factor 16.
