Index: lib/CodeGen/MachineInstr.cpp
===================================================================
--- lib/CodeGen/MachineInstr.cpp	(revision 163653)
+++ lib/CodeGen/MachineInstr.cpp	(working copy)
@@ -834,7 +834,8 @@
   // If opcodes or number of operands are not the same then the two
   // instructions are obviously not identical.
   if (Other->getOpcode() != getOpcode() ||
-      Other->getNumOperands() != getNumOperands())
+      Other->getNumOperands() != getNumOperands() ||
+      Other->memoperands_empty() != memoperands_empty())
     return false;
 
   if (isBundle()) {
@@ -850,6 +851,20 @@
     }
   }
 
+  if (!memoperands_empty()) {
+    // If we have mem operands, make sure that the sizes of the memoperands for
+    // each MI are the same. The values can be different, so lets only check
+    // the sizes. If the sizes between one of the memoperands differ, then the
+    // instructions are not identical.
+    for (MachineInstr::mmo_iterator mb1 = memoperands_begin(),
+        mb2 = Other->memoperands_begin(),
+        me = memoperands_end(); mb1 != me; ++mb1, ++mb2) {
+      if ((*mb1)->getSize() != (*mb2)->getSize()) {
+        return false;
+      }
+    }
+  }
+
   // Check operands to make sure they match.
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = getOperand(i);