From f8fe20b224e983e7cb930a04ed6b574cf0f01d60 Mon Sep 17 00:00:00 2001
From: Jim Wilson <wilson@gcc.gnu.org>
Date: Thu, 27 Jun 1996 15:48:57 -0700
Subject: [PATCH] (extract_bit_field): Check TRULY_NOOP_TRUNCATION before
 making a SUBREG of a REG.

From-SVN: r12338
---
 gcc/expmed.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/expmed.c b/gcc/expmed.c
index be27f855ae8..a5939423034 100644
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -928,7 +928,9 @@ extract_bit_field (str_rtx, bitsize, bitnum, unsignedp,
      So too extracting a subword value in
      the least significant part of the register.  */
 
-  if ((GET_CODE (op0) == REG
+  if (((GET_CODE (op0) == REG
+	&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+				  GET_MODE_BITSIZE (GET_MODE (op0))))
        || (GET_CODE (op0) == MEM
 	   && (! SLOW_UNALIGNED_ACCESS
 	       || (offset * BITS_PER_UNIT % bitsize == 0
-- 
2.30.2