I made scheduling to fail when we end up with an empty domain but as
I forgot to actually check the return value of build_original_schedule
the fix was equivalent to just doing nothing to the schedule when
it has an empty domain. I verified that for the testcase it DCEs
the relevant stmt and that this is a valid transform.
Bootstrapped and tested on x86_64-unknown-linux-gnu, SPEC 2k6 is also
happy with this.
Committed as obvious (since no functional change).
Richard.
2017-10-12 Richard Biener <rguent...@suse.de>
PR tree-optimization/69728
Revert
2017-09-19 Richard Biener <rguent...@suse.de>
PR tree-optimization/69728
* graphite-sese-to-poly.c (schedule_error): New global.
(add_loop_schedule): Handle empty domain by failing the
schedule.
(build_original_schedule): Handle schedule_error.
* graphite-sese-to-poly.c (add_loop_schedule): Handle empty
domain by returning an unchanged schedule.
* gcc.dg/graphite/pr69728.c: Adjust to reflect we can handle
the loop now. Remove unrelated undefined behavior.
Index: gcc/graphite-sese-to-poly.c
===================================================================
--- gcc/graphite-sese-to-poly.c (revision 253645)
+++ gcc/graphite-sese-to-poly.c (working copy)
@@ -1066,8 +1051,6 @@ outer_projection_mupa (__isl_take isl_un
return isl_multi_union_pw_aff_from_union_pw_multi_aff (data.res);
}
-static bool schedule_error;
-
/* Embed SCHEDULE in the constraints of the LOOP domain. */
static isl_schedule *
@@ -1082,11 +1065,9 @@ add_loop_schedule (__isl_take isl_schedu
return empty < 0 ? isl_schedule_free (schedule) : schedule;
isl_union_set *domain = isl_schedule_get_domain (schedule);
- /* We cannot apply an empty domain to pbbs in this loop so fail.
- ??? Somehow drop pbbs in the loop instead. */
+ /* We cannot apply an empty domain to pbbs in this loop so return early. */
if (isl_union_set_is_empty (domain))
{
- schedule_error = true;
isl_union_set_free (domain);
return schedule;
}
@@ -1216,8 +1197,6 @@ build_schedule_loop_nest (scop_p scop, i
static bool
build_original_schedule (scop_p scop)
{
- schedule_error = false;
-
int i = 0;
int n = scop->pbbs.length ();
while (i < n)
@@ -1232,14 +1211,6 @@ build_original_schedule (scop_p scop)
scop->original_schedule = add_in_sequence (scop->original_schedule, s);
}
- if (schedule_error)
- {
- if (dump_file)
- fprintf (dump_file, "[sese-to-poly] failed to build "
- "original schedule\n");
- return false;
- }
-
if (dump_file)
{
fprintf (dump_file, "[sese-to-poly] original schedule:\n");
Index: gcc/testsuite/gcc.dg/graphite/pr69728.c
===================================================================
--- gcc/testsuite/gcc.dg/graphite/pr69728.c (revision 253645)
+++ gcc/testsuite/gcc.dg/graphite/pr69728.c (working copy)
@@ -1,7 +1,7 @@
/* { dg-do compile } */
-/* { dg-options "-O3 -floop-nest-optimize" } */
+/* { dg-options "-O3 -floop-nest-optimize -fdump-tree-graphite-details" } */
-int a[1];
+int a[9];
int b, c, d, e;
void
fn1 ()
@@ -19,3 +19,9 @@ fn1 ()
}
}
}
+
+/* At the moment only ISL figures that if (d) is always true. We've
+ run into scheduling issues before here, not being able to handle
+ empty domains. */
+
+/* { dg-final { scan-tree-dump "loop nest optimized" "graphite" } } */
