re PR tree-optimization/32721 (CCP removes volatile qualifiers.)

2007-07-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/32721
	* tree-ssa-ccp.c (maybe_fold_stmt_indirect): Preserve
	TREE_THIS_VOLATILE on the folded reference.
	* tree-ssa-operands.c (get_expr_operands): Set has_volatile_ops
	if the array reference has TREE_THIS_VOLATILE set.

	* gcc.dg/pr32721.c: New testcase.

From-SVN: r126624

gcc/ChangeLog

+2007-07-13  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/32721
+	* tree-ssa-ccp.c (maybe_fold_stmt_indirect): Preserve
+	TREE_THIS_VOLATILE on the folded reference.
+	* tree-ssa-operands.c (get_expr_operands): Set has_volatile_ops
+	if the array reference has TREE_THIS_VOLATILE set.
+
 2007-07-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR other/32188

gcc/testsuite/ChangeLog

+2007-07-13  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/32721
+	* gcc.dg/pr32721.c: New testcase.
+
 2007-07-13  Hans-Peter Nilsson  <hp@axis.com>
 
 	* gcc.dg/20011127-1.c: Use dg-message, not dg-error to match the

gcc/testsuite/gcc.dg/pr32721.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+int spinlock[2];
+int main ()
+{
+volatile int * spinlock0;
+volatile int * spinlock1;
+spinlock0 = &spinlock[0];
+spinlock1 = &spinlock[1];
+
+*spinlock0 = 0;
+*spinlock1 = 0;
+ while (*spinlock0);
+}
+
+/* { dg-final { scan-tree-dump "= spinlock.0." "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-ssa-ccp.c

@@ -1839,6 +1839,7 @@ static tree
 maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
 {
   tree t;
+  bool volatile_p = TREE_THIS_VOLATILE (expr);
 
   /* We may well have constructed a double-nested PLUS_EXPR via multiple
      substitutions.  Fold that down to one.  Remove NON_LVALUE_EXPRs that
@@ -1882,7 +1883,10 @@ maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
       t = maybe_fold_offset_to_reference (base_addr, offset,
 					  TREE_TYPE (expr));
       if (t)
-	return t;
+	{
+	  TREE_THIS_VOLATILE (t) = volatile_p;
+	  return t;
+	}
     }
   else
     {

gcc/tree-ssa-operands.c

@@ -2078,6 +2078,9 @@ get_expr_operands (tree stmt, tree *expr_p, int flags)
 
 	    if (!none)
 	      flags |= opf_no_vops;
+
+	    if (TREE_THIS_VOLATILE (expr))
+	      get_stmt_ann (stmt)->has_volatile_ops = true;
 	  }
 	else if (TREE_CODE (ref) == INDIRECT_REF)
 	  {