* fold-const.c (tree_expr_nonnegative_p): Treat truth values as

	non-negative.

testsuite:
	* gcc.dg/compare3.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@38374 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 6 insertions, 2 deletions

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index d8131faf226..a0a76b2d491 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7299,8 +7299,12 @@ tree_expr_nonnegative_p (t)
       return rtl_expr_nonnegative_p (RTL_EXPR_RTL (t));
       
     default:
-      /* We don't know sign of `t', so be safe and return false.  */
-      return 0;
+      if (truth_value_p (TREE_CODE (t)))
+	/* Truth values evaluate to 0 or 1, which is nonnegative.  */
+	return 1;
+      else
+	/* We don't know sign of `t', so be conservative and return false.  */
+	return 0;
     }
 }