From 2166571b8f1a95012072e563d4c112da24d11167 Mon Sep 17 00:00:00 2001
From: Richard Stallman <rms@gnu.org>
Date: Wed, 14 Oct 1992 01:20:21 +0000
Subject: [PATCH] (simplify_binary_operation): Insure that folded >> extends
 the sign even if the host bootstrap compiler doesn't.

From-SVN: r2446
---
 gcc/cse.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gcc/cse.c b/gcc/cse.c
index 89cd43316e0..12255b0e769 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -3964,6 +3964,12 @@ simplify_binary_operation (code, mode, op0, op1)
 	return 0;
 
       val = arg0s >> arg1;
+
+      /* Bootstrap compiler may not have sign extended the right shift.
+	 Manually extend the sign to insure bootstrap cc matches gcc.  */
+      if (arg0s < 0 && arg1 > 0)
+	val |= ((HOST_WIDE_INT) -1) << (HOST_BITS_PER_WIDE_INT - arg1);
+
       break;
 
     case ROTATERT:
-- 
2.30.2