From e7b9fb45d5550493972d74fbdd512f9712e5521c Mon Sep 17 00:00:00 2001
From: Ian Rogers <ian.rogers@manchester.ac.uk>
Date: Sun, 28 Jun 2009 04:16:46 +0100
Subject: [PATCH] Avoid problems with moveable objects breaking LIR canonical
 form.

---
 rvm/src/org/jikesrvm/compilers/opt/Simplifier.java | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/rvm/src/org/jikesrvm/compilers/opt/Simplifier.java b/rvm/src/org/jikesrvm/compilers/opt/Simplifier.java
index b8bdf7faa..707b16736 100644
--- a/rvm/src/org/jikesrvm/compilers/opt/Simplifier.java
+++ b/rvm/src/org/jikesrvm/compilers/opt/Simplifier.java
@@ -3837,20 +3837,20 @@ private static DefUseEffect refLoad(Instruction s, OptOptions opts) {
   }
 
   /**
-   * To reduce the number of conditions to consider, we
-   * transform all commutative
-   * operators to a canoncial form.  The following forms are considered
-   * canonical:
+   * To reduce the number of conditions to consider, we transform all commutative
+   * operators to a canoncial form.  The following forms are considered canonical:
    * <ul>
    * <li> <code> Reg = Reg <op> Reg </code>
    * <li> <code> Reg = Reg <op> Constant </code>
    * <li> <code> Reg = Constant <op> Constant </code>
    * </ul>
+	* For object constant operands we treat movable objects like registers.
    */
   private static void canonicalizeCommutativeOperator(Instruction instr) {
-    if (Binary.getVal1(instr).isConstant()) {
-      Operand tmp = Binary.getClearVal1(instr);
-      Binary.setVal1(instr, Binary.getClearVal2(instr));
+	 Operand op1 = Binary.getVal1(instr);
+    if (op1.isConstant() && !op1.isMovableObjectConstant()) {
+	   Operand tmp = Binary.getClearVal1(instr);
+	   Binary.setVal1(instr, Binary.getClearVal2(instr));
       Binary.setVal2(instr, tmp);
     }
   }