re PR middle-end/38422 (union/bitfield causes cc1/cc1plus to run out of memory.)

	PR middle-end/38422
	* fold-const.c (fold_unary) <CASE_CONVERT>: Don't convert MULT_EXPR
	operands to mult_type if it isn't narrower than op0's type.

	* gcc.c-torture/execute/pr38422.c: New test.

From-SVN: r142521

gcc/ChangeLog

+2008-12-06  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/38422
+	* fold-const.c (fold_unary) <CASE_CONVERT>: Don't convert MULT_EXPR
+	operands to mult_type if it isn't narrower than op0's type.
+
 2008-12-06  Jan Hubicka  <jh@suse.cz>
 	    Jakub Jelinek <jakub@redhat.com>
 

gcc/fold-const.c

@@ -8351,11 +8351,16 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	    mult_type = type;
 	  else
 	    mult_type = unsigned_type_for (type);
-	  
-	  tem = fold_build2 (MULT_EXPR, mult_type,
-			     fold_convert (mult_type, TREE_OPERAND (op0, 0)),
-			     fold_convert (mult_type, TREE_OPERAND (op0, 1)));
-	  return fold_convert (type, tem);
+
+	  if (TYPE_PRECISION (mult_type) < TYPE_PRECISION (TREE_TYPE (op0)))
+	    {
+	      tem = fold_build2 (MULT_EXPR, mult_type,
+				 fold_convert (mult_type,
+					       TREE_OPERAND (op0, 0)),
+				 fold_convert (mult_type,
+					       TREE_OPERAND (op0, 1)));
+	      return fold_convert (type, tem);
+	    }
 	}
 
       tem = fold_convert_const (code, type, op0);

gcc/testsuite/ChangeLog

+2008-12-06  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/38422
+	* gcc.c-torture/execute/pr38422.c: New test.
+
 2008-12-06  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/38415

gcc/testsuite/gcc.c-torture/execute/pr38422.c

+/* PR middle-end/38422 */
+
+extern void abort (void);
+
+struct S
+{
+  int s : (sizeof (int) * __CHAR_BIT__ - 2);
+} s;
+
+void
+foo (void)
+{
+  s.s *= 2;
+}
+
+int
+main ()
+{
+  s.s = 24;
+  foo ();
+  if (s.s != 48)
+    abort ();
+  return 0;
+}