Richard Guenther wrote:
> On Wed, Apr 25, 2012 at 3:34 PM, Greta Yorsh <greta.yo...@arm.com>
> wrote:
> > Richard Guenther wrote:
> >> On Wed, Apr 25, 2012 at 1:51 PM, Greta Yorsh <greta.yo...@arm.com>
> >> wrote:
> >> > The test gcc.dg/vect/slp-perm-8.c fails on arm-none-eabi with neon
> >> enabled:
> >> > FAIL: gcc.dg/vect/slp-perm-8.c scan-tree-dump-times vect
> "vectorized
> >> 1
> >> > loops" 2
> >> >
> >> > The test expects 2 loops to be vectorized, while gcc successfully
> >> vectorizes
> >> > 3 loops in this test using neon on arm. This patch adjusts the
> >> expected
> >> > output. Fixed test passes on qemu for arm and powerpc.
> >> >
> >> > OK for trunk?
> >>
> >> I think the proper fix is to instead of
> >>
> >> for (i = 0; i < N; i++)
> >> {
> >> input[i] = i;
> >> output[i] = 0;
> >> if (input[i] > 256)
> >> abort ();
> >> }
> >>
> >> use
> >>
> >> for (i = 0; i < N; i++)
> >> {
> >> input[i] = i;
> >> output[i] = 0;
> >> __asm__ volatile ("");
> >> }
> >>
> >> to prevent vectorization of initialization loops.
> >
> > Actually, it looks like both arm and powerpc vectorize this
> initialization loop (line 31), because the control flow is hoisted
> outside the loop by previous optimizations. In addition, arm with neon
> vectorizes the second loop (line 39), but powerpc does not:
> >
> > 39: not vectorized: relevant stmt not supported: D.2163_8 = i_40 * 9;
> >
> > If this is the expected behaviour for powerpc, then the patch I
> proposed is still needed to fix the test failure on arm. Also, there
> would be no need to disable vectorization of the initialization loop,
> right?
>
> Ah, I thought that was what changed. Btw, the if () abort () tries to
> disable
> vectorization but does not succeed in doing so.
>
> Richard.
Here is an updated patch. It prevents vectorization of the initialization
loop, as Richard suggested, and updates the expected number of vectorized
loops accordingly. This patch assumes that the second loop in main (line 39)
should only be vectorized on arm with neon. The test passes for arm and
powerpc.
OK for trunk?
Thank you,
Greta
gcc/testsuite/ChangeLog
2012-04-25 Greta Yorsh <greta.yo...@arm.com>
* gcc.dg/vect/slp-perm-8.c (main): Prevent
vectorization of initialization loop.
(dg-final): Adjust the expected number of
vectorized loops.
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
b/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
index d211ef9..aaa6cbb 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
@@ -32,8 +32,7 @@ int main (int argc, const char* argv[])
{
input[i] = i;
output[i] = 0;
- if (input[i] > 256)
- abort ();
+ __asm__ volatile ("");
}
for (i = 0; i < N / 3; i++)
@@ -52,7 +51,8 @@ int main (int argc, const char* argv[])
return 0;
}
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" { target
vect_perm_byte } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 2 "vect" { target {
vect_perm_byte && arm_neon_ok } } } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target {
vect_perm_byte && {! arm_neon_ok } } } } } */
/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" {
target vect_perm_byte } } } */
/* { dg-final { cleanup-tree-dump "vect" } } */
