Transfer physical register spill info when load / store folding happens.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48246 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index 7ebf31e..63d5b87 100644
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -268,6 +268,8 @@
       }
     }
 
+    /// @brief - transfer spill point information from one instruction to
+    /// another.
     void transferSpillPts(MachineInstr *Old, MachineInstr *New) {
       std::map<MachineInstr*,std::vector<std::pair<unsigned,bool> > >::iterator
         I = SpillPt2VirtMap.find(Old);
@@ -343,6 +345,21 @@
       return EmergencySpillMap[MI];
     }
 
+    /// @brief - transfer emergency spill information from one instruction to
+    /// another.
+    void transferEmergencySpills(MachineInstr *Old, MachineInstr *New) {
+      std::map<MachineInstr*,std::vector<unsigned> >::iterator I =
+        EmergencySpillMap.find(Old);
+      if (I == EmergencySpillMap.end())
+        return;
+      while (!I->second.empty()) {
+        unsigned virtReg = I->second.back();
+        I->second.pop_back();
+        addEmergencySpill(virtReg, New);
+      }
+      EmergencySpillMap.erase(I);
+    }
+
     /// @brief return or get a emergency spill slot for the register class.
     int getEmergencySpillSlot(const TargetRegisterClass *RC);