[llvm-commits] [llvm] r40803 - /llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

[Chris Lattner]

Author: lattner
Date: Fri Aug  3 20:07:49 2007
New Revision: 40803

URL: http://llvm.org/viewvc/llvm-project?rev=40803&view=rev
Log:
avoid an unneeded vector copy.  This speeds up mem2reg on the testcase 
in PR1432 by 6%

Modified:
    llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

Modified: llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp?rev=40803&r1=40802&r2=40803&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/PromoteMemoryToRegister.cpp Fri Aug  3 20:07:49 2007
@@ -76,11 +76,18 @@
   // Data package used by RenamePass()
   class VISIBILITY_HIDDEN RenamePassData {
   public:
+    RenamePassData() {}
     RenamePassData(BasicBlock *B, BasicBlock *P,
                    const std::vector<Value *> &V) : BB(B), Pred(P), Values(V) {}
     BasicBlock *BB;
     BasicBlock *Pred;
     std::vector<Value *> Values;
+    
+    void swap(RenamePassData &RHS) {
+      std::swap(BB, RHS.BB);
+      std::swap(Pred, RHS.Pred);
+      Values.swap(RHS.Values);
+    }
   };
 
   struct VISIBILITY_HIDDEN PromoteMem2Reg {
@@ -406,7 +413,8 @@
   std::vector<RenamePassData> RenamePassWorkList;
   RenamePassWorkList.push_back(RenamePassData(F.begin(), 0, Values));
   while(!RenamePassWorkList.empty()) {
-    RenamePassData RPD = RenamePassWorkList.back(); 
+    RenamePassData RPD;
+    RPD.swap(RenamePassWorkList.back());
     RenamePassWorkList.pop_back();
     // RenamePass may add new worklist entries.
     RenamePass(RPD.BB, RPD.Pred, RPD.Values, RenamePassWorkList);