On Wed, 4 Jun 2014, Richard Biener wrote:
So I'd say we should instead simply bail out if the middle-bb has a PHI node.
Sounds good to me, so I am testing the mini-patch I had originally posted
to bugzilla:
2014-06-04 Marc Glisse <marc.gli...@inria.fr>
PR tree-optimization/61385
gcc/
* tree-ssa-phiopt.c (value_replacement): Punt if there are PHI nodes.
gcc/testsuite/
* gcc.dg/tree-ssa/pr61385.c: New file.
--
Marc GlisseIndex: gcc/testsuite/gcc.dg/tree-ssa/pr61385.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/pr61385.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/pr61385.c (working copy)
@@ -0,0 +1,43 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#define assert(x) if (!(x)) __builtin_abort ()
+
+int a, b, c, d, e, f, g;
+
+int
+fn1 ()
+{
+ int *h = &c;
+ for (; c < 1; c++)
+ {
+ int *i = &a, *k = &a;
+ f = 0;
+ if (b)
+ return 0;
+ if (*h)
+ {
+ int **j = &i;
+ *j = 0;
+ d = 0;
+ }
+ else
+ g = e = 0;
+ if (*h)
+ {
+ int **l = &k;
+ *l = &g;
+ }
+ d &= *h;
+ assert (k == &a || k);
+ assert (i);
+ }
+ return 0;
+}
+
+int
+main ()
+{
+ fn1 ();
+ return 0;
+}
Index: gcc/tree-ssa-phiopt.c
===================================================================
--- gcc/tree-ssa-phiopt.c (revision 211221)
+++ gcc/tree-ssa-phiopt.c (working copy)
@@ -842,20 +842,24 @@ value_replacement (basic_block cond_bb,
/* Now optimize (x != 0) ? x + y : y to just y.
The following condition is too restrictive, there can easily be another
stmt in middle_bb, for instance a CONVERT_EXPR for the second argument.
*/
gimple assign = last_and_only_stmt (middle_bb);
if (!assign || gimple_code (assign) != GIMPLE_ASSIGN
|| gimple_assign_rhs_class (assign) != GIMPLE_BINARY_RHS
|| (!INTEGRAL_TYPE_P (TREE_TYPE (arg0))
&& !POINTER_TYPE_P (TREE_TYPE (arg0))))
return 0;
+ /* Punt if there are (degenerate) PHIs in middle_bb, there should not be. */
+ if (!gimple_seq_empty_p (phi_nodes (middle_bb)))
+ return 0;
+
/* Only transform if it removes the condition. */
if (!single_non_singleton_phi_for_edges (phi_nodes (gimple_bb (phi)), e0,
e1))
return 0;
/* Size-wise, this is always profitable. */
if (optimize_bb_for_speed_p (cond_bb)
/* The special case is useless if it has a low probability. */
&& profile_status_for_fn (cfun) != PROFILE_ABSENT
&& EDGE_PRED (middle_bb, 0)->probability < PROB_EVEN
/* If assign is cheap, there is no point avoiding it. */
