(fold): Don't record overflow when negating unsigned constants.

From-SVN: r10779

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index cf57a37..ba459c0 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3549,7 +3549,7 @@ fold (expr)
              TREE_TYPE (t) = type;
              TREE_OVERFLOW (t)
                = (TREE_OVERFLOW (arg0)
-                  | force_fit_type (t, overflow));
+                  | force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
              TREE_CONSTANT_OVERFLOW (t)
                = TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
            }