PR middle-end/40204

	* fold-const.c (fold_binary) <case BIT_AND_EXPR>: Avoid infinite
	recursion if build_int_cst_type returns the same INTEGER_CST as
	arg1.

	* gcc.c-torture/compile/pr40204.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@147749 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 25d73d9..8770426 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2009-05-20  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/40204
+       * fold-const.c (fold_binary) <case BIT_AND_EXPR>: Avoid infinite
+       recursion if build_int_cst_type returns the same INTEGER_CST as
+       arg1.
+
 2009-05-20  Eric Botcazou  <ebotcazou@adacore.com>
 
        * fold-const.c (build_fold_addr_expr_with_type): Take the address of

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 0ac9e29..e322ecb 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -11382,6 +11382,8 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
              if (prec < HOST_BITS_PER_WIDE_INT
                  || newmask == ~(unsigned HOST_WIDE_INT) 0)
                {
+                 tree newmaskt;
+
                  if (shift_type != TREE_TYPE (arg0))
                    {
                      tem = fold_build2 (TREE_CODE (arg0), shift_type,
@@ -11392,9 +11394,9 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
                    }
                  else
                    tem = op0;
-                 return fold_build2 (BIT_AND_EXPR, type, tem,
-                                     build_int_cst_type (TREE_TYPE (op1),
-                                                         newmask));
+                 newmaskt = build_int_cst_type (TREE_TYPE (op1), newmask);
+                 if (!tree_int_cst_equal (newmaskt, arg1))
+                   return fold_build2 (BIT_AND_EXPR, type, tem, newmaskt);
                }
            }
        }

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cca56e5..465ae00 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2009-05-20  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/40204
+       * gcc.c-torture/compile/pr40204.c: New test.
+
 2009-05-20  Richard Guenther  <rguenther@suse.de>
 
        * gcc.c-torture/compile/20090518-1.c: New testcase.

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr40204.c b/gcc/testsuite/gcc.c-torture/compile/pr40204.c
new file mode 100644 (file)
index 0000000..3193284
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr40204.c
@@ -0,0 +1,14 @@
+/* PR middle-end/40204 */
+
+struct S
+{
+  unsigned int a : 4;
+  unsigned int b : 28;
+} s;
+char c;
+
+void
+f (void)
+{
+  s.a = (c >> 4) & ~(1 << 4);
+}