From b2d75f49553c81190a22ce2edf453b2acc312b7a Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Thu, 8 Aug 2019 19:24:58 -0400
Subject: [PATCH] tcg: Fix constant folding of INDEX_op_extract2_i32

On a 64-bit host, discard any replications of the 32-bit
sign bit when performing the shift and merge.

Backports commit 80f4d7c3ae216c191fb403e149bcba88d6aa40bb from qemu
---
 qemu/tcg/optimize.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/qemu/tcg/optimize.c b/qemu/tcg/optimize.c
index 6483bcf8..8ae4922f 100644
--- a/qemu/tcg/optimize.c
+++ b/qemu/tcg/optimize.c
@@ -1213,8 +1213,8 @@ void tcg_optimize(TCGContext *s)
                 if (opc == INDEX_op_extract2_i64) {
                     tmp = (v1 >> op->args[3]) | (v2 << (64 - op->args[3]));
                 } else {
-                    tmp = (v1 >> op->args[3]) | (v2 << (32 - op->args[3]));
-                    tmp = (int32_t)tmp;
+                    tmp = (int32_t)(((uint32_t)v1 >> op->args[3]) |
+                                    ((uint32_t)v2 << (32 - op->args[3])));
                 }
                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
                 break;