From patchwork Thu Aug 12 14:35:04 2010
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Subject: Fix make_range (PR middle-end/45262)
Date: Thu, 12 Aug 2010 04:35:04 -0000
From: Jakub Jelinek <jakub@redhat.com>
X-Patchwork-Id: 61614
Message-Id: <20100812143504.GP702@tyan-ft48-01.lab.bos.redhat.com>
To: gcc-patches@gcc.gnu.org

Hi!

The range folding code in fold-const.c expects ranges to have always
low <= high (with NULL being -inf resp. +inf), and for PLUS_EXPR/MINUS_EXPR
the code normalizes, but not so for NEGATE_EXPR.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux.
Ok for trunk/4.5/4.4?

2010-08-12  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/45262
	* fold-const.c (make_range) <case NEGATE_EXPR>: Punt if
	-a overflows.  Normalize the range.

	* gcc.c-torture/execute/pr45262.c: New test.


	Jakub


--- gcc/fold-const.c.jj	2010-07-09 13:44:24.000000000 +0200
+++ gcc/fold-const.c	2010-08-12 13:44:42.000000000 +0200
@@ -3985,9 +3985,9 @@ make_range (tree exp, int *pin_p, tree *
 	  n_high = range_binop (MINUS_EXPR, exp_type,
 				build_int_cst (exp_type, 0),
 				0, low, 0);
-	  low = n_low, high = n_high;
-	  exp = arg0;
-	  continue;
+	  if (n_high != 0 && TREE_OVERFLOW (n_high))
+	    break;
+	  goto normalize;
 
 	case BIT_NOT_EXPR:
 	  /* ~ X -> -X - 1  */
@@ -4021,6 +4021,7 @@ make_range (tree exp, int *pin_p, tree *
 	  if (TYPE_OVERFLOW_UNDEFINED (arg0_type))
 	    *strict_overflow_p = true;
 
+	normalize:
 	  /* Check for an unsigned range which has wrapped around the maximum
 	     value thus making n_high < n_low, and normalize it.  */
 	  if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
--- gcc/testsuite/gcc.c-torture/execute/pr45262.c.jj	2010-08-12 13:51:49.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr45262.c	2010-08-12 13:51:21.000000000 +0200
@@ -0,0 +1,33 @@
+/* PR middle-end/45262 */
+
+extern void abort (void);
+
+int
+foo (unsigned int x)
+{
+  return ((int) x < 0) || ((int) (-x) < 0);
+}
+
+int
+bar (unsigned int x)
+{
+  return x >> 31 || (-x) >> 31;
+}
+
+int
+main (void)
+{
+  if (foo (1) != 1)
+    abort ();
+  if (foo (0) != 0)
+    abort ();
+  if (foo (-1) != 1)
+    abort ();
+  if (bar (1) != 1)
+    abort ();
+  if (bar (0) != 0)
+    abort ();
+  if (bar (-1) != 1)
+    abort ();
+  return 0;
+}