From 9f0caad0e43f97a4613850b3874b851cb1bc301d Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Wed, 8 Nov 2017 12:53:05 +0100
Subject: [PATCH] Fix FOLD rule for strength reduction of widening.

Reported by Matthew Burk.
---
 src/lj_opt_fold.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lj_opt_fold.c b/src/lj_opt_fold.c
index 3d0e35a6f9..5dc7ae3da9 100644
--- a/src/lj_opt_fold.c
+++ b/src/lj_opt_fold.c
@@ -1052,7 +1052,7 @@ LJFOLDF(simplify_conv_sext)
   if (ref == J->scev.idx) {
     IRRef lo = J->scev.dir ? J->scev.start : J->scev.stop;
     lua_assert(irt_isint(J->scev.t));
-    if (lo && IR(lo)->i + ofs >= 0) {
+    if (lo && IR(lo)->o == IR_KINT && IR(lo)->i + ofs >= 0) {
     ok_reduce:
 #if LJ_TARGET_X64
       /* Eliminate widening. All 32 bit ops do an implicit zero-extension. */