diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index e9bfe76..c76a222 100644
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -87,6 +87,11 @@
             v2pMap_[virtReg] = NO_PHYS_REG;
         }
 
+        void clearAllVirt() {
+            v2pMap_.clear();
+            grow();
+        }
+
         bool hasStackSlot(unsigned virtReg) const {
             return getStackSlot(virtReg) != NO_STACK_SLOT;
         }