PR tree-optimization/18431

	* fold-const.c (associate_trees): Do not produce x + 0.
	(fold_widened_comparison, fold_sign_changed_comparison): New functions.
	(fold): Use them.
	* tree-ssa-loop-niter.c (upper_bound_in_type, lower_bound_in_type):
	Moved ...
	* tree.c (upper_bound_in_type, lower_bound_in_type): Here.
	* tree.h (upper_bound_in_type, lower_bound_in_type): Declare.

	* testsuite/gcc.c-torture/execute/20041114-1.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@90646 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 72 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index a05dab73f73..654ce785857 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -6074,4 +6074,76 @@ get_case_label (tree t)
   return CASE_LEADER_OR_LABEL (t);
 }
 
+/* Returns the largest value obtainable by casting something in INNER type to
+   OUTER type.  */
+
+tree
+upper_bound_in_type (tree outer, tree inner)
+{
+  unsigned HOST_WIDE_INT lo, hi;
+  unsigned bits = TYPE_PRECISION (inner);
+
+  if (TYPE_UNSIGNED (outer) || TYPE_UNSIGNED (inner))
+    {
+      /* Zero extending in these cases.  */
+      if (bits <= HOST_BITS_PER_WIDE_INT)
+	{
+	  hi = 0;
+	  lo = (~(unsigned HOST_WIDE_INT) 0)
+		  >> (HOST_BITS_PER_WIDE_INT - bits);
+	}
+      else
+	{
+	  hi = (~(unsigned HOST_WIDE_INT) 0)
+		  >> (2 * HOST_BITS_PER_WIDE_INT - bits);
+	  lo = ~(unsigned HOST_WIDE_INT) 0;
+	}
+    }
+  else
+    {
+      /* Sign extending in these cases.  */
+      if (bits <= HOST_BITS_PER_WIDE_INT)
+	{
+	  hi = 0;
+	  lo = (~(unsigned HOST_WIDE_INT) 0)
+		  >> (HOST_BITS_PER_WIDE_INT - bits) >> 1;
+	}
+      else
+	{
+	  hi = (~(unsigned HOST_WIDE_INT) 0)
+		  >> (2 * HOST_BITS_PER_WIDE_INT - bits) >> 1;
+	  lo = ~(unsigned HOST_WIDE_INT) 0;
+	}
+    }
+
+  return fold_convert (outer,
+		       build_int_cst_wide (inner, lo, hi));
+}
+
+/* Returns the smallest value obtainable by casting something in INNER type to
+   OUTER type.  */
+
+tree
+lower_bound_in_type (tree outer, tree inner)
+{
+  unsigned HOST_WIDE_INT lo, hi;
+  unsigned bits = TYPE_PRECISION (inner);
+
+  if (TYPE_UNSIGNED (outer) || TYPE_UNSIGNED (inner))
+    lo = hi = 0;
+  else if (bits <= HOST_BITS_PER_WIDE_INT)
+    {
+      hi = ~(unsigned HOST_WIDE_INT) 0;
+      lo = (~(unsigned HOST_WIDE_INT) 0) << (bits - 1);
+    }
+  else
+    {
+      hi = (~(unsigned HOST_WIDE_INT) 0) << (bits - HOST_BITS_PER_WIDE_INT - 1);
+      lo = 0;
+    }
+
+  return fold_convert (outer,
+		       build_int_cst_wide (inner, lo, hi));
+}
+
 #include "gt-tree.h"