From: Matthias Klose <doko@ubuntu.com>
Date: Thu, 22 Nov 2007 15:34:03 +0000 (+0000)
Subject: backport: re PR middle-end/34130 (the builtin abs() gives wrong result when used... 
X-Git-Tag: prereleases/gcc-4.2.3-rc1~118
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e72534af59f446593d4802ca4fcc2611a0154716;p=thirdparty%2Fgcc.git

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

2007-11-22  Matthias Klose  <doko@ubuntu.com>

        Backport from mainline:
        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.

        PR middle-end/34130
        * gcc.c-torture/execute/pr34130.c: New testcase.

From-SVN: r130352
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 63f136354f02..9541b91049b5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2007-11-22  Matthias Klose  <doko@ubuntu.com>
+
+	Backport from mainline:
+	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.
+
 2007-11-22  Richard Sandiford  <rsandifo@nildram.co.uk>
 
 	PR rtl-optimization/33848
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index b2a3fa6a3147..81b1d4f84cd8 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -5660,6 +5660,9 @@ 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 1aef4f96bd53..88df27b9d7d3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2007-11-22  Matthias Klose  <doko@ubuntu.com>
+
+	Backport from mainline:
+	2007-11-17  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/34130
+	* gcc.c-torture/execute/pr34130.c: New testcase.
+
 2007-11-22  Richard Sandiford  <rsandifo@nildram.co.uk>
 
 	PR rtl-optimization/33848
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;
+}