* fold-const.c (make_range): Only narrow to signed range if

        the signed range is smaller than the unsigned range.

	* gcc.c-torture/execute/20020911-1.c: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@57050 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 701bd4c..914ae17 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2002-09-11  Hartmut Penner  <hpenner@de.ibm.com>
+
+       * fold-const.c (make_range): Only narrow to signed range if
+       the signed range is smaller than the unsigned range.
+
 2002-09-12  Alan Modra  <amodra@bigpond.net.au>
 
        * emit-rtl.c (set_mem_size): New function.

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index b8da1a7..1b2124a 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3089,9 +3089,10 @@ make_range (exp, pin_p, plow, phigh)
                = TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type)
                  : TYPE_MAX_VALUE (type);
 
-             high_positive = fold (build (RSHIFT_EXPR, type,
-                                          convert (type, high_positive),
-                                          convert (type, integer_one_node)));
+             if (TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (exp)))
+               high_positive = fold (build (RSHIFT_EXPR, type,
+                                            convert (type, high_positive),
+                                            convert (type, integer_one_node)));
 
              /* If the low bound is specified, "and" the range with the
                 range for which the original unsigned value will be

diff --git a/gcc/testsuite/gcc.c-torture/execute/20020911-1.c b/gcc/testsuite/gcc.c-torture/execute/20020911-1.c
new file mode 100644 (file)
index 0000000..ec83022
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20020911-1.c
@@ -0,0 +1,8 @@
+extern void abort (void);
+unsigned short c = 0x8000;
+int main()
+{
+  if ((c-0x8000) < 0 || (c-0x8000) > 0x7fff)
+    abort();
+  return 0;
+}