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.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@142521 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 248ba67..89d28bc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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>
 

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 719b787..8c0cb1d 100644 (file)
--- a/gcc/fold-const.c
+++ b/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);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2c7ee3c..bf19792 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+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

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr38422.c b/gcc/testsuite/gcc.c-torture/execute/pr38422.c
new file mode 100644 (file)
index 0000000..e36879d
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr38422.c
@@ -0,0 +1,24 @@
+/* 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;
+}