From a2cd028f5fd512c04e4fdce69d4398d13b51cfb9 Mon Sep 17 00:00:00 2001
From: Janis Johnson <janis187@us.ibm.com>
Date: Wed, 6 Feb 2002 22:13:01 +0000
Subject: [PATCH] loop.c (remove_constant_addition): Avoid clobbering a shared
 CONST expression.

	* loop.c (remove_constant_addition): Avoid clobbering a shared
	CONST expression.

Co-Authored-By: Jan Hubicka <jh@suse.cz>

From-SVN: r49556
---
 gcc/ChangeLog |  6 ++++++
 gcc/loop.c    | 13 ++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 778b0d7c621..6b413d62b1c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2002-02-06  Janis Johnson  <janis187@us.ibm.com>
+	    Jan Hubicka  <jh@suse.cz>
+
+	* loop.c (remove_constant_addition): Avoid clobbering a shared
+	CONST expression.
+
 2002-02-06  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* config.gcc (s390x-*-linux*): Add t-linux64 makefile fragment.
diff --git a/gcc/loop.c b/gcc/loop.c
index 0067e7490fd..e0847a8c32f 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -3683,8 +3683,19 @@ remove_constant_addition (x)
   HOST_WIDE_INT addval = 0;
   rtx exp = *x;
 
+  /* Avoid clobbering a shared CONST expression.  */
   if (GET_CODE (exp) == CONST)
-    exp = XEXP (exp, 0);
+    {
+      if (GET_CODE (XEXP (exp, 0)) == PLUS
+	  && GET_CODE (XEXP (XEXP (exp, 0), 0)) == SYMBOL_REF
+	  && GET_CODE (XEXP (XEXP (exp, 0), 1)) == CONST_INT)
+	{
+	  *x = XEXP (XEXP (exp, 0), 0);
+	  return INTVAL (XEXP (XEXP (exp, 0), 1));
+	}
+      return 0;
+    }
+
   if (GET_CODE (exp) == CONST_INT)
     {
       addval = INTVAL (exp);