re PR tree-optimization/47280 (ICE: verify_stmts failed: statement marked for…

re PR tree-optimization/47280 (ICE: verify_stmts failed: statement marked for throw, but doesn't with -fnon-call-exceptions -ftrapv)

2011-01-14  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/47280
	* tree-ssa-forwprop.c (associate_plusminus): Cleanup EH and
	return CFG changes.
	(tree_ssa_forward_propagate_single_use_vars): Deal with
	CFG changes from associate_plusminus.

	* g++.dg/opt/pr47280.C: New testcase.

From-SVN: r168784

gcc/ChangeLog

 2011-01-14  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/47280
+	* tree-ssa-forwprop.c (associate_plusminus): Cleanup EH and
+	return CFG changes.
+	(tree_ssa_forward_propagate_single_use_vars): Deal with
+	CFG changes from associate_plusminus.
+
+2011-01-14  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/47281
 	Revert
 	2011-01-11  Richard Guenther  <rguenther@suse.de>

gcc/testsuite/ChangeLog

+2011-01-14  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/47280
+	* g++.dg/opt/pr47280.C: New testcase.
+
 2011-01-14  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/constexpr-regress1.C: New.

gcc/testsuite/g++.dg/opt/pr47280.C

+// { dg-do compile }
+// { dg-options "-O -fnon-call-exceptions -ftrapv" }
+
+void bar (int n, char *p)
+{
+  try
+    {
+      n++;
+      for (int i = 0; i < n - 1; i++)
+	p[i];
+    }
+  catch (...)
+    {}
+}
+

gcc/tree-ssa-forwprop.c

@@ -1658,9 +1658,9 @@ simplify_bitwise_and (gimple_stmt_iterator *gsi, gimple stmt)
 
 
 /* Perform re-associations of the plus or minus statement STMT that are
-   always permitted.  */
+   always permitted.  Returns true if the CFG was changed.  */
 
-static void
+static bool
 associate_plusminus (gimple stmt)
 {
   tree rhs1 = gimple_assign_rhs1 (stmt);
@@ -1671,7 +1671,7 @@ associate_plusminus (gimple stmt)
 
   /* We can't reassociate at all for saturating types.  */
   if (TYPE_SATURATING (TREE_TYPE (rhs1)))
-    return;
+    return false;
 
   /* First contract negates.  */
   do
@@ -1934,7 +1934,12 @@ out:
     {
       fold_stmt_inplace (stmt);
       update_stmt (stmt);
+      if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
+	  && gimple_purge_dead_eh_edges (gimple_bb (stmt)))
+	return true;
     }
+
+  return false;
 }
 
 /* Main entry point for the forward propagation optimizer.  */
@@ -2062,7 +2067,7 @@ tree_ssa_forward_propagate_single_use_vars (void)
 	      else if (gimple_assign_rhs_code (stmt) == PLUS_EXPR
 		       || gimple_assign_rhs_code (stmt) == MINUS_EXPR)
 		{
-		  associate_plusminus (stmt);
+		  cfg_changed |= associate_plusminus (stmt);
 		  gsi_next (&gsi);
 		}
 	      else