Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2018-09-19 Richard Biener <rguent...@suse.de>
PR tree-optimization/87349
PR tree-optimization/87342
* tree-ssa-sccvn.c (do_rpo_vn): Iterate max_rpo computation.
* gcc.dg/torture/pr87349-1.c: New testcase.
* gcc.dg/torture/pr87349-2.c: Likewise.
* gcc.dg/torture/pr87342.c: Likewise.
Index: gcc/tree-ssa-sccvn.c
===================================================================
--- gcc/tree-ssa-sccvn.c (revision 264390)
+++ gcc/tree-ssa-sccvn.c (working copy)
@@ -6374,6 +6374,7 @@ do_rpo_vn (function *fn, edge entry, bit
vn_valueize = rpo_vn_valueize;
/* Initialize the unwind state and edge/BB executable state. */
+ bool need_max_rpo_iterate = false;
for (int i = 0; i < n; ++i)
{
basic_block bb = BASIC_BLOCK_FOR_FN (fn, rpo[i]);
@@ -6388,11 +6389,14 @@ do_rpo_vn (function *fn, edge entry, bit
if (e->flags & EDGE_DFS_BACK)
has_backedges = true;
e->flags &= ~EDGE_EXECUTABLE;
- if (e == entry)
+ if (iterate || e == entry)
continue;
if (bb_to_rpo[e->src->index] > i)
- rpo_state[i].max_rpo = MAX (rpo_state[i].max_rpo,
- bb_to_rpo[e->src->index]);
+ {
+ rpo_state[i].max_rpo = MAX (rpo_state[i].max_rpo,
+ bb_to_rpo[e->src->index]);
+ need_max_rpo_iterate = true;
+ }
else
rpo_state[i].max_rpo
= MAX (rpo_state[i].max_rpo,
@@ -6403,6 +6407,35 @@ do_rpo_vn (function *fn, edge entry, bit
entry->flags |= EDGE_EXECUTABLE;
entry->dest->flags |= BB_EXECUTABLE;
+ /* When there are irreducible regions the simplistic max_rpo computation
+ above for the case of backedges doesn't work and we need to iterate
+ until there are no more changes. */
+ unsigned nit = 0;
+ while (need_max_rpo_iterate)
+ {
+ nit++;
+ need_max_rpo_iterate = false;
+ for (int i = 0; i < n; ++i)
+ {
+ basic_block bb = BASIC_BLOCK_FOR_FN (fn, rpo[i]);
+ edge e;
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ if (e == entry)
+ continue;
+ int max_rpo = MAX (rpo_state[i].max_rpo,
+ rpo_state[bb_to_rpo[e->src->index]].max_rpo);
+ if (rpo_state[i].max_rpo != max_rpo)
+ {
+ rpo_state[i].max_rpo = max_rpo;
+ need_max_rpo_iterate = true;
+ }
+ }
+ }
+ }
+ statistics_histogram_event (cfun, "RPO max_rpo iterations", nit);
+
/* As heuristic to improve compile-time we handle only the N innermost
loops and the outermost one optimistically. */
if (iterate)
Index: gcc/testsuite/gcc.dg/torture/pr87349-1.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr87349-1.c (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr87349-1.c (working copy)
@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+
+void
+h1 (int *fh, int pw)
+{
+ *fh = 0;
+ if (*fh != 0)
+ for (;;)
+ {
+ fh = &pw;
+
+ if (pw == 0)
+ {
+ }
+ else
+ while (pw < 1)
+ {
+ if (pw == 0)
+ {
+ut:
+ ;
+ }
+
+ ++pw;
+ }
+
+ if (pw == 0)
+ goto ut;
+ }
+
+ goto ut;
+}
+
Index: gcc/testsuite/gcc.dg/torture/pr87349-2.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr87349-2.c (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr87349-2.c (working copy)
@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+
+void
+h1 (int *fh, int pw)
+{
+ *fh = 0;
+ if (*fh != 0)
+ for (;;)
+ {
+ fh = &pw;
+
+ if (pw == 0)
+ {
+ }
+ else
+ while (pw < 1)
+ {
+ if (pw == 0)
+ {
+ut:
+ ;
+ }
+
+ ++pw;
+ }
+
+ if (pw == *fh)
+ goto ut;
+ }
+
+ goto ut;
+}
+
Index: gcc/testsuite/gcc.dg/torture/pr87342.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr87342.c (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr87342.c (working copy)
@@ -0,0 +1,44 @@
+/* { dg-do compile } */
+
+int ix;
+
+void
+o6 (int rh)
+{
+ if (rh == 0)
+ {
+ ix = 0;
+ while (ix < 1)
+ {
+ }
+
+ for (;;)
+ if (ix == 0)
+ while (rh < 1)
+ {
+ if (rh == 0)
+ {
+ __builtin_unreachable ();
+
+kp:
+ if (ix == 0)
+ {
+hk:
+ ix = 0;
+ }
+ }
+
+ while (rh < 1)
+ if (ix == 0)
+ goto kp;
+
+ while (rh < 1)
+ {
+ }
+ }
+ else
+ goto kp;
+ }
+
+ goto hk;
+}
