re PR middle-end/36137 (gcc can't do math)

	PR middle-end/36137
	* fold-const.c (fold_binary): Use STRIP_SIGN_NOPS instead of
	STRIP_NOPS on arguments even for MIN_EXPR and MAX_EXPR.

	* gcc.c-torture/execute/20080506-1.c: New test.

From-SVN: r135028

4 files changed, 34 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6147e35..20ee05c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,14 +1,14 @@
 2008-05-07  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/36137
+	* fold-const.c (fold_binary): Use STRIP_SIGN_NOPS instead of
+	STRIP_NOPS on arguments even for MIN_EXPR and MAX_EXPR.
+
 	PR middle-end/36106
 	* omp-low.c (expand_omp_atomic_pipeline): Load value using the
 	integral type rather than floating point, then VIEW_CONVERT_EXPR
 	to the floating point type.
 
-	* testsuite/libgomp.c/atomic-5.c: New test.
-	* testsuite/libgomp.c/atomic-6.c: New test.
-	* testsuite/libgomp.c/autopar-1.c: New test.
-
 2008-05-07  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.c (ix86_expand_copysign): Force non-zero constant
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index b4645ca..db7be87 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -1,6 +1,6 @@
 /* Fold a constant sub-tree into a single node for C-compiler
    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
+   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -9261,7 +9261,8 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
      safe for every expression, except for a comparison expression
      because its signedness is derived from its operands.  So, in
      the latter case, only strip conversions that don't change the
-     signedness.
+     signedness.  MIN_EXPR/MAX_EXPR also need signedness of arguments
+     preserved.
 
      Note that this is done as an internal manipulation within the
      constant folder, in order to find the simplest representation
@@ -9269,7 +9270,7 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
      cases, the appropriate type conversions should be put back in
      the tree that will get out of the constant folder.  */
 
-  if (kind == tcc_comparison)
+  if (kind == tcc_comparison || code == MIN_EXPR || code == MAX_EXPR)
     {
       STRIP_SIGN_NOPS (arg0);
       STRIP_SIGN_NOPS (arg1);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e2d2bb8..a36aa5a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-05-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/36137
+	* gcc.c-torture/execute/20080506-1.c: New test.
+
 2008-05-06  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libfortran/34974
diff --git a/gcc/testsuite/gcc.c-torture/execute/20080506-1.c b/gcc/testsuite/gcc.c-torture/execute/20080506-1.c
new file mode 100644
index 0000000..4f6d6d8
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20080506-1.c
@@ -0,0 +1,21 @@
+/* PR middle-end/36137 */
+extern void abort (void);
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+int
+main ()
+{
+  unsigned int u;
+  int i = -1;
+
+  u = MAX ((unsigned int) MAX (i, 0), 1);
+  if (u != 1)
+    abort ();
+
+  u = MIN ((unsigned int) MAX (i, 0), (unsigned int) i);
+  if (u != 0)
+    abort ();
+  return 0;
+}