From: Richard Guenther <rguenther@suse.de>
Date: Sat, 17 Nov 2007 14:22:42 +0000 (+0000)
Subject: re PR middle-end/34130 (the builtin abs() gives wrong result when used in some expres... 
X-Git-Tag: releases/gcc-4.3.0~1465
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a0857153ddb27ba0f64a16c934734421fd2fccfc;p=thirdparty%2Fgcc.git

re PR middle-end/34130 (the builtin abs() gives wrong result when used in some expression)

2007-11-17  Richard Guenther  <rguenther@suse.de>

	PR middle-end/34130
	* fold-const.c (extract_muldiv_1): Do not move negative
	constants inside ABS_EXPR.

	* gcc.c-torture/execute/pr34130.c: New testcase.

From-SVN: r130258
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2bef81feb0d5..3151f57deb06 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2007-11-17  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/34130
+	* fold-const.c (extract_muldiv_1): Do not move negative
+	constants inside ABS_EXPR.
+
 2007-11-16  Ian Lance Taylor  <iant@google.com>
 
 	* collect2.c (dump_file): If a demangled symbol is followed by a
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 1057d2609a19..1c03f30894ad 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -6095,6 +6095,9 @@ extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type,
             }
           break;
         }
+      /* If the constant is negative, we cannot simplify this.  */
+      if (tree_int_cst_sgn (c) == -1)
+        break;
       /* FALLTHROUGH */
     case NEGATE_EXPR:
       if ((t1 = extract_muldiv (op0, c, code, wide_type, strict_overflow_p))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bec1ea53bcdf..1386cebca7d4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-11-17  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/34130
+	* gcc.c-torture/execute/pr34130.c: New testcase.
+
 2007-11-17  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	PR fortran/34108
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr34130.c b/gcc/testsuite/gcc.c-torture/execute/pr34130.c
new file mode 100644
index 000000000000..b528ff22b8a1
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr34130.c
@@ -0,0 +1,12 @@
+extern void abort (void);
+int foo (int i)
+{
+  return -2 * __builtin_abs(i - 2);
+}
+int main()
+{
+  if (foo(1) != -2
+      || foo(3) != -2)
+    abort ();
+  return 0;
+}