1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 1d3f96f..b73019b 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -2621,6 +2621,14 @@ expand_gimple_cond (basic_block bb, gcond *stmt)
       && TREE_CODE (op1) == INTEGER_CST)
     code = maybe_optimize_mod_cmp (code, &op0, &op1);
 
+  /* Optimize (x - y) < 0 into x < y if x - y has undefined overflow.  */
+  if (!TYPE_UNSIGNED (TREE_TYPE (op0))
+      && (code == LT_EXPR || code == LE_EXPR
+	  || code == GT_EXPR || code == GE_EXPR)
+      && integer_zerop (op1)
+      && TREE_CODE (op0) == SSA_NAME)
+    maybe_optimize_sub_cmp_0 (code, &op0, &op1);
+
   last2 = last = get_last_insn ();
 
   extract_true_false_edges_from_block (bb, &true_edge, &false_edge);