https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85693
Bug ID: 85693
Summary: Generation of SAD (Sum of Absolute Difference)
instruction
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ubizjak at gmail dot com
Target Milestone: ---
As mentioned in [1], page 7, following code:
--cut here--
#include <stdlib.h>
#define N 1024
unsigned char pix1[N], pix2[N];
int foo (void)
{
int i_sum = 0;
int i;
for (i = 0; i < N; i++)
i_sum += abs (pix1[i] - pix2[i]);
return i_sum;
}
--cut here--
should vectorize to psadbw instruction.
[1]
http://llvm.org/devmtg/2018-04/slides/Das-An%20Introduction%20to%20AMD%20Optimizing%20Compiler.pdf
