Hi!
On Mon, Oct 08, 2012 at 10:01:53AM +0000, Kumar, Venkataramanan wrote:
Both the testcases fail on i686-linux unfortunately:
Excess errors:
/usr/src/gcc/gcc/testsuite/gcc.dg/pr53397-1.c:1:0: warning:
-fprefetch-loop-arrays not supported for this target (try -march switches)
[enabled by default]
Guess you need to add -msse2 to dg-options (for x86_64 it doesn't
change anything, but for i686 it does). Furthermore, as the testcases
are limited to x86_64/i686, I wonder why the tests didn't go into
gcc/testsuite/gcc.target/i386/ directory instead.
> >> --- gcc/testsuite/gcc.dg/pr53397-1.c (revision 0)
> >> +++ gcc/testsuite/gcc.dg/pr53397-1.c (revision 0)
> >> @@ -0,0 +1,28 @@
> >> +/* Prefetching when the step is loop invariant. */
> >> +
> >> +/* { dg-do compile } */
> >> +/* { dg-options "-O3 -fprefetch-loop-arrays -fdump-tree-aprefetch-details
> >> --param min-insn-to-prefetch-ratio=3 --param simultaneous-prefetches=10
> >> -fdump-tree-aprefetch-details" }
> >> +*/
> >> +
> >> +
> >> +double data[16384];
> >> +void prefetch_when_non_constant_step_is_invariant(int step, int n) {
> >> + int a;
> >> + int b;
> >> + for (a = 1; a < step; a++) {
> >> + for (b = 0; b < n; b += 2 * step) {
> >> +
> >> + int i = 2*(b + a);
> >> + int j = 2*(b + a + step);
> >> +
> >> +
> >> + data[j] = data[i];
> >> + data[j+1] = data[i+1];
> >> + }
> >> + }
> >> +}
> >> +
> >> +/* { dg-final { scan-tree-dump "Issued prefetch" "aprefetch" } } */
> >> +/* { dg-final { scan-assembler "prefetcht0" } } */
> >
> > This (and the case below) needs to be adjusted to only run on the
> > appropriate hardware. See for example gcc.dg/tree-ssa/prefetch-8.c for how
> > to do this.
> >
> >> +/* { dg-final { cleanup-tree-dump "aprefetch" } } */
> >> --- gcc/testsuite/gcc.dg/pr53397-2.c (revision 0)
> >> +++ gcc/testsuite/gcc.dg/pr53397-2.c (revision 0)
> >> @@ -0,0 +1,29 @@
> >> +/* Not prefetching when the step is loop variant. */
> >> +
> >> +/* { dg-do compile } */
> >> +/* { dg-options "-O3 -fprefetch-loop-arrays -fdump-tree-aprefetch-details
> >> --param min-insn-to-prefetch-ratio=3 --param simultaneous-prefetches=10
> >> -fdump-tree-aprefetch-details" }
> >> +*/
> >> +
> >> +
> >> +double data[16384];
> >> +void donot_prefetch_when_non_constant_step_is_variant(int step, int
> >> +n) {
> >> + int a;
> >> + int b;
> >> + for (a = 1; a < step; a++,step*=2) {
> >> + for (b = 0; b < n; b += 2 * step) {
> >> +
> >> + int i = 2*(b + a);
> >> + int j = 2*(b + a + step);
> >> +
> >> +
> >> + data[j] = data[i];
> >> + data[j+1] = data[i+1];
> >> + }
> >> + }
> >> +}
> >> +
> >> +/* { dg-final { scan-tree-dump "Not prefetching" "aprefetch" } } */
> >> +/* { dg-final { scan-tree-dump "loop variant step" "aprefetch" } }
> >> +*/
> >> +
> >> +/* { dg-final { cleanup-tree-dump "aprefetch" } } */
> >> +
Jakub
