re PR middle-end/45262 (Optimization results in wrong result on expression x>>31...

	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.

From-SVN: r163193

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 09da08d61763a45433a56bef14f52f93ddf4c42c..31dd288030ffc7c2ac4a4d0960b7c5a0b002d43a 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,10 @@
        * builtins.c (fold_builtin_memory_op): Avoid -Wsign-compare
        warning.
 
+       PR middle-end/45262
+       * fold-const.c (make_range) <case NEGATE_EXPR>: Punt if
+       -a overflows.  Normalize the range.
+
 2010-08-12  Richard Guenther  <rguenther@suse.de>
 
        PR tree-optimization/45232

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 9ca5eff554e209d91b7b6a228a1ddd5f91ac27a0..d63411ea89aa708964fa72290600cb9332601c0d 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3985,9 +3985,9 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh,
          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 *plow, tree *phigh,
          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))

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index dd180c655e56366b14f1d9f316900c169fbbfe3d..840253dcaf32e99696258195c6b4c6a15c668dc0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-12  Jakub Jelinek  <jakub@redhat.com>
+
+       PR middle-end/45262
+       * gcc.c-torture/execute/pr45262.c: New test.
+
 2010-08-12  Uros Bizjak  <ubizjak@gmail.com>
 
        * gcc.dg/profile-generate-3.c: Call dg-require-profiling with

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr45262.c b/gcc/testsuite/gcc.c-torture/execute/pr45262.c
new file mode 100644 (file)
index 0000000..72e186b
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr45262.c
@@ -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;
+}