re PR middle-end/36077 (Expressions result is wrong)

2008-04-29  Richard Guenther  <rguenther@suse.de>

	PR middle-end/36077
	* fold-const.c (extract_muldiv_1): In combining division constants
	make sure to never overflow.

	* gcc.c-torture/execute/pr36077.c: New testcase.

From-SVN: r134792

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1c7cba1c5684240f98a9dd31454b6fe6d0f53fc3..3ffe3bc08f3db19193897dd1ec6872999df0fad6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-04-29  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/36077
+       * fold-const.c (extract_muldiv_1): In combining division constants
+       make sure to never overflow.
+
 2008-04-29  Nick Clifton  <nickc@redhat.com>
 
        * doc/tm.texi (RETURN_ADDR_RTX): Fix typo.

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index a4d5760b8619c9409844315f0d8b91ed78bb709d..aae203777289cb5e39a4dc9799af674705a27714 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -5953,8 +5953,13 @@ extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type,
       /* If these are the same operation types, we can associate them
         assuming no overflow.  */
       if (tcode == code
-         && 0 != (t1 = const_binop (MULT_EXPR, fold_convert (ctype, op1),
-                                    fold_convert (ctype, c), 0))
+         && 0 != (t1 = int_const_binop (MULT_EXPR, fold_convert (ctype, op1),
+                                        fold_convert (ctype, c), 1))
+         && 0 != (t1 = force_fit_type_double (ctype, TREE_INT_CST_LOW (t1),
+                                              TREE_INT_CST_HIGH (t1),
+                                              (TYPE_UNSIGNED (ctype)
+                                               && tcode != MULT_EXPR) ? -1 : 1,
+                                              TREE_OVERFLOW (t1)))
          && !TREE_OVERFLOW (t1))
        return fold_build2 (tcode, ctype, fold_convert (ctype, op0), t1);
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f6bb5e1aadc4361a0f5943902bd9986a49061d50..f2b69e90afca2484067642d0d7f7291653c7d5bf 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-04-29  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/36077
+       * gcc.c-torture/execute/pr36077.c: New testcase.
+
 2008-04-29  Kai Tietz  <kai.tietz@onevision.com>
 
        * testsuite/gcc.dg/sync-2.c: Set dg-options "-ansi".

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr36077.c b/gcc/testsuite/gcc.c-torture/execute/pr36077.c
new file mode 100644 (file)
index 0000000..09636a1
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr36077.c
@@ -0,0 +1,13 @@
+extern void abort (void);
+
+unsigned int test (unsigned int x)
+{
+  return x / 0x80000001U / 0x00000002U;
+}
+
+int main()
+{
+  if (test(2) != 0)
+    abort ();
+  return 0;
+}