re PR tree-optimization/61438 (ICE on valid code at -O3 on x86_64-linux-gnu in in loop_preheader_edge, at cfgloop.c:1668)

2014-06-10  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/61438
	* tree-ssa-pre.c (eliminate_dom_walker): Add do_pre member.
	(eliminate_dom_walker::before_dom_children): Only try to inhibit
	insertion of IVs if running PRE.
	(eliminate): Adjust.
	(pass_pre::execute): Likewise.
	(pass_fre::execute): Likewise.

	* gcc.dg/torture/pr61438.c: New testcase.

From-SVN: r211413

4 files changed, 74 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7d37ddb..180d1c8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2014-06-10  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/61438
+	* tree-ssa-pre.c (eliminate_dom_walker): Add do_pre member.
+	(eliminate_dom_walker::before_dom_children): Only try to inhibit
+	insertion of IVs if running PRE.
+	(eliminate): Adjust.
+	(pass_pre::execute): Likewise.
+	(pass_fre::execute): Likewise.
+
+2014-06-10  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/61456
 	* tree-ssa-alias.c (nonoverlapping_component_refs_of_decl_p):
 	Do not use the main variant for the type comparison.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f3f1162..53b6134 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2014-06-10  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/61438
+	* gcc.dg/torture/pr61438.c: New testcase.
+
+2014-06-10  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/61456
 	* g++.dg/opt/pr61456.C: New testcase.
 
diff --git a/gcc/testsuite/gcc.dg/torture/pr61438.c b/gcc/testsuite/gcc.dg/torture/pr61438.c
new file mode 100644
index 0000000..2381999
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr61438.c
@@ -0,0 +1,48 @@
+/* { dg-do run } */
+
+extern void abort (void);
+
+int a, c, **d, e, g;
+static int b = 1;
+
+struct
+{
+  int f0;
+} f;
+
+void
+foo ()
+{
+  int h, *i = &a;
+  for (; e;)
+    {
+      for (c = 0; c < 1; c++)
+	for (; b;)
+	  ;
+      for (;;)
+	{
+	  if (a)
+	    {
+	      for (; f.f0; f.f0++)
+		;
+	      if (g)
+		break;
+	    }
+	  for (h = 0; h < 2; h++)
+	    {
+	      i = *d;
+	      if (!i)
+		abort ();
+	    }
+	}
+    }
+  if (!i)
+    abort ();
+}
+
+int
+main ()
+{
+  foo (); 
+  return 0;
+}
diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c
index f497f90..89e94e9 100644
--- a/gcc/tree-ssa-pre.c
+++ b/gcc/tree-ssa-pre.c
@@ -3992,10 +3992,13 @@ eliminate_insert (gimple_stmt_iterator *gsi, tree val)
 class eliminate_dom_walker : public dom_walker
 {
 public:
-  eliminate_dom_walker (cdi_direction direction) : dom_walker (direction) {}
+  eliminate_dom_walker (cdi_direction direction, bool do_pre_)
+      : dom_walker (direction), do_pre (do_pre_) {}
 
   virtual void before_dom_children (basic_block);
   virtual void after_dom_children (basic_block);
+
+  bool do_pre;
 };
 
 /* Perform elimination for the basic-block B during the domwalk.  */
@@ -4192,7 +4195,8 @@ eliminate_dom_walker::before_dom_children (basic_block b)
 		 variable.  In other cases the vectorizer won't do anything
 		 anyway (either it's loop invariant or a complicated
 		 expression).  */
-	      if (flag_tree_loop_vectorize
+	      if (do_pre
+		  && flag_tree_loop_vectorize
 		  && gimple_assign_single_p (stmt)
 		  && TREE_CODE (sprime) == SSA_NAME
 		  && loop_outer (b->loop_father))
@@ -4434,7 +4438,7 @@ eliminate_dom_walker::after_dom_children (basic_block)
 /* Eliminate fully redundant computations.  */
 
 static unsigned int
-eliminate (void)
+eliminate (bool do_pre)
 {
   gimple_stmt_iterator gsi;
   gimple stmt;
@@ -4448,7 +4452,8 @@ eliminate (void)
   el_avail.create (0);
   el_avail_stack.create (0);
 
-  eliminate_dom_walker (CDI_DOMINATORS).walk (cfun->cfg->x_entry_block_ptr);
+  eliminate_dom_walker (CDI_DOMINATORS,
+			do_pre).walk (cfun->cfg->x_entry_block_ptr);
 
   el_avail.release ();
   el_avail_stack.release ();
@@ -4779,7 +4784,7 @@ pass_pre::execute (function *fun)
   gsi_commit_edge_inserts ();
 
   /* Remove all the redundant expressions.  */
-  todo |= eliminate ();
+  todo |= eliminate (true);
 
   statistics_counter_event (fun, "Insertions", pre_stats.insertions);
   statistics_counter_event (fun, "PA inserted", pre_stats.pa_insert);
@@ -4864,7 +4869,7 @@ pass_fre::execute (function *fun)
   memset (&pre_stats, 0, sizeof (pre_stats));
 
   /* Remove all the redundant expressions.  */
-  todo |= eliminate ();
+  todo |= eliminate (false);
 
   todo |= fini_eliminate ();