diff --git a/src/cpu/o3/rename_map.cc b/src/cpu/o3/rename_map.cc
index d1876a9..1b831d9 100644
--- a/src/cpu/o3/rename_map.cc
+++ b/src/cpu/o3/rename_map.cc
@@ -76,14 +76,14 @@
     PhysRegIdPtr renamed_reg;
     // Record the current physical register that is renamed to the
     // requested architected register.
-    PhysRegIdPtr prev_reg = map[arch_reg.index()];
+    PhysRegIdPtr prev_reg = map[arch_reg.flatIndex()];
 
     // If it's not referencing the zero register, then rename the
     // register.
     if (arch_reg != zeroReg) {
         renamed_reg = freeList->getReg();
 
-        map[arch_reg.index()] = renamed_reg;
+        map[arch_reg.flatIndex()] = renamed_reg;
     } else {
         // Otherwise return the zero register so nothing bad happens.
         assert(prev_reg->isZeroReg());
@@ -92,8 +92,8 @@
 
     DPRINTF(Rename, "Renamed reg %d to physical reg %d (%d) old mapping was"
             " %d (%d)\n",
-            arch_reg, renamed_reg->index(), renamed_reg->flatIndex(),
-            prev_reg->index(), prev_reg->flatIndex());
+            arch_reg, renamed_reg->flatIndex(), renamed_reg->flatIndex(),
+            prev_reg->flatIndex(), prev_reg->flatIndex());
 
     return RenameInfo(renamed_reg, prev_reg);
 }