It is beneficial to unroll reduction loop (and split the reduction target) to
reduce dependence height due to recurrence, but GCC does not perform such
optimization (-O3 -fno-tree-vectorize)
int a[1000];
int b[1000];
int foo(int n)
{
int s = 0;
int i = 0;
for (i = 0; i < 1000 ; i++)
{
s += a[i] + b[2*i];
}
return s;
}
--
Summary: Sum-reduction loop not recognized
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: xinliangli at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35343
