Hi,
this patches fixes a 5/6 regression PR69426.
When compiling the test-case in the patch, the verify_ssa todo check
fails after removing a clobber in eliminate_local_variables_stmt.
The problem is that the clobber is removed, but the uses of the
corresponding vdef are not changed, and the virtual symbol is not marked
for renaming.
[ The same happens in 4.9, but because omp_expand_local is called before
verify_ssa, the ICE does not happen. In 5.0 and later, we use a separate
expand_omp_ssa pass. ]
This patch fixes the problem by replacing the uses of the vdef of the
clobber by the vuse of the clobber.
The patch uses replace_uses_by, but unlink_vdef_stmt also works, I'm not
sure which one to use.
Bootstrapped and reg-tested on x86_64.
OK for trunk, gcc-5-branch?
Thanks,
- Tom
Fix clobber removal in parloops
2016-01-23 Tom de Vries
PR tree-optimization/69426
* tree-parloops.c (eliminate_local_variables_stmt): Handle vdef of
removed clobber.
* gcc.dg/autopar/pr69426.c: New test.
---
gcc/testsuite/gcc.dg/autopar/pr69426.c | 19 +++
gcc/tree-parloops.c| 1 +
2 files changed, 20 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/autopar/pr69426.c b/gcc/testsuite/gcc.dg/autopar/pr69426.c
new file mode 100644
index 000..e91421c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/autopar/pr69426.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-parallelize-loops=2" } */
+
+int iq;
+
+void
+mr(void)
+{
+ unsigned int i8;
+
+ for (i8 = 0; i8 != 1; i8 += 3) {
+void *f0[] = { f0 };
+int hv;
+
+for (; hv < 1; ++hv)
+ iq = 0;
+ }
+ ++iq;
+}
diff --git a/gcc/tree-parloops.c b/gcc/tree-parloops.c
index 7749d34..f9db43b 100644
--- a/gcc/tree-parloops.c
+++ b/gcc/tree-parloops.c
@@ -725,6 +725,7 @@ eliminate_local_variables_stmt (edge entry, gimple_stmt_iterator *gsi,
}
else if (gimple_clobber_p (stmt))
{
+ replace_uses_by (gimple_vdef (stmt), gimple_vuse (stmt));
stmt = gimple_build_nop ();
gsi_replace (gsi, stmt, false);
dta.changed = true;
