I am testing the following patch to fix another case where call
shrink-wrapping fails to update PHIs properly. The previous fix
missed the case where the destination contained a degenerate PHI
thus we can simply propagate those out.
Bootstrap and regtest running on x86_64-unknown-linux-gnu (for trunk
where the testcase doesn't show the latent issue). I'll backport
later.
Richard.
2016-01-10 Richard Biener <rguent...@suse.de>
PR tree-optimization/79034
* tree-call-cdce.c (shrink_wrap_one_built_in_call_with_conds):
Propagate out degenerate PHIs in the joiner.
* g++.dg/torture/pr79034.C: New testcase.
Index: gcc/tree-call-cdce.c
===================================================================
--- gcc/tree-call-cdce.c (revision 244260)
+++ gcc/tree-call-cdce.c (working copy)
@@ -805,7 +805,18 @@ shrink_wrap_one_built_in_call_with_conds
if (EDGE_COUNT (join_tgt_in_edge_from_call->dest->preds) > 1)
join_tgt_bb = split_edge (join_tgt_in_edge_from_call);
else
- join_tgt_bb = join_tgt_in_edge_from_call->dest;
+ {
+ join_tgt_bb = join_tgt_in_edge_from_call->dest;
+ /* We may have degenerate PHIs in the destination. Propagate
+ those out. */
+ for (gphi_iterator i = gsi_start_phis (join_tgt_bb); !gsi_end_p (i);)
+ {
+ gphi *phi = i.phi ();
+ replace_uses_by (gimple_phi_result (phi),
+ gimple_phi_arg_def (phi, 0));
+ remove_phi_node (&i, true);
+ }
+ }
}
else
{
Index: gcc/testsuite/g++.dg/torture/pr79034.C
===================================================================
--- gcc/testsuite/g++.dg/torture/pr79034.C (nonexistent)
+++ gcc/testsuite/g++.dg/torture/pr79034.C (working copy)
@@ -0,0 +1,52 @@
+/* { dg-do compile } */
+
+extern "C" {
+ float sqrtf(float);
+}
+
+class T {
+public:
+ float floats[1];
+
+ inline float length() const {
+ return sqrtf(floats[0]);
+ }
+};
+
+void destruct(void *);
+
+class Container {
+
+ T Ts[1];
+
+public:
+ ~Container() {
+ destruct((void *)Ts);
+ }
+
+ T& operator[](int n) {
+ return Ts[0];
+ }
+};
+
+void fill(Container&);
+
+void doit()
+{
+ Container data;
+ float max = 10;
+
+ int i, j, k;
+
+ for (i = 0; i < 10; i++) {
+ for (j = 1; j < 10; j++) {
+ if (max < 5)
+ break;
+ fill( data);
+ max = data[0].length();
+ for (k = 1; k < j; k++) {
+ max = 5;
+ }
+ }
+ }
+}
