IRgen optimization: cache the value of 'this' and 'vtt' instead of

repeatedly reloading from an alloca.  We still need to create the alloca
for debug info purposes (although we currently create it in all cases
because of some abstraction boundaries that're hard to break down).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96403 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index a4db556d39..a694b894df 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -382,11 +382,13 @@ private:
   /// CXXThisDecl - When generating code for a C++ member function,
   /// this will hold the implicit 'this' declaration.
   ImplicitParamDecl *CXXThisDecl;
+  llvm::Value *CXXThisValue;
 
   /// CXXVTTDecl - When generating code for a base object constructor or
   /// base object destructor with virtual bases, this will hold the implicit
   /// VTT parameter.
   ImplicitParamDecl *CXXVTTDecl;
+  llvm::Value *CXXVTTValue;
   
   /// CXXLiveTemporaryInfo - Holds information about a live C++ temporary.
   struct CXXLiveTemporaryInfo {
@@ -745,11 +747,17 @@ public:
 
   /// LoadCXXThis - Load the value of 'this'. This function is only valid while
   /// generating code for an C++ member function.
-  llvm::Value *LoadCXXThis();
+  llvm::Value *LoadCXXThis() {
+    assert(CXXThisValue && "no 'this' value for this function");
+    return CXXThisValue;
+  }
 
   /// LoadCXXVTT - Load the VTT parameter to base constructors/destructors have
   /// virtual bases.
-  llvm::Value *LoadCXXVTT();
+  llvm::Value *LoadCXXVTT() {
+    assert(CXXVTTValue && "no VTT value for this function");
+    return CXXVTTValue;
+  }
 
   /// GetAddressOfBaseOfCompleteClass - Convert the given pointer to a
   /// complete class down to one of its virtual bases.