re PR tree-optimization/33615 (Hoisting of potentially-throwing values for -fnon-call-exceptions)

gcc/
	PR tree-optimization/33615
	* tree-ssa-loop-im.c (movement_possibility): Return MOVE_IMPOSSIBLE
	if the rhs might throw.

gcc/testsuite/
	PR tree-optimization/33615
	* g++.dg/tree-ssa/pr33615.C: New test.

From-SVN: r129163

gcc/ChangeLog

+2007-10-09  Richard Sandiford  <rsandifo@nildram.co.uk>
+
+	PR tree-optimization/33615
+	* tree-ssa-loop-im.c (movement_possibility): Return MOVE_IMPOSSIBLE
+	if the rhs might throw.
+
 2007-10-09  Jan Hubicka  <jh@suse.cz>
 
 	* invoke.texi (align-threshold, align-loop-iterations): Document.

gcc/testsuite/ChangeLog

+2007-10-09  Richard Sandiford  <rsandifo@nildram.co.uk>
+
+	PR tree-optimization/33615
+	* g++.dg/tree-ssa/pr33615.C: New test.
+
 2007-10-08  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR tree-optimization/33572

gcc/testsuite/g++.dg/tree-ssa/pr33615.C

+/* { dg-do compile } */
+/* { dg-options "-O -fnon-call-exceptions -fdump-tree-lim-details -w" } */
+
+extern volatile int y;
+
+double
+foo (double a, int x)
+{
+  while (x--)
+    {
+      y++;
+      a += 1.0 / 0.0;
+    }
+  return a;
+}
+
+// The expression 1.0 / 0.0 should not be treated as a loop invariant
+// if it may throw an exception.
+// { dg-final { scan-tree-dump-times "invariant up to" 0 "lim" } }
+// { dg-final { cleanup-tree-dump "lim" } }

gcc/tree-ssa-loop-im.c

@@ -260,7 +260,8 @@ movement_possibility (tree stmt)
 
   rhs = GIMPLE_STMT_OPERAND (stmt, 1);
 
-  if (TREE_SIDE_EFFECTS (rhs))
+  if (TREE_SIDE_EFFECTS (rhs)
+      || tree_could_throw_p (rhs))
     return MOVE_IMPOSSIBLE;
 
   if (TREE_CODE (lhs) != SSA_NAME