Edited DFG2LLVM pass

1. Bug fix
2. Properly remove or replace intrinsics

llvm/lib/Transforms/DFG2LLVM/DFG2LLVM.cpp

@@ -57,7 +57,6 @@ namespace {
     void codeGen(DFLeafNode* N) {
 
       std::vector<IntrinsicInst *> IItoRemove;
-      std::vector<std::pair<IntrinsicInst *, Value *> > IItoReplace;
       BuildDFG::HandleToDFNode Leaf_HandleToDFNodeMap;
 
       // Get the function associated woth the dataflow node      
@@ -91,12 +90,13 @@ namespace {
               // get the parent node of the arg node
               // get argument node
               ArgII = cast<IntrinsicInst>((II->getOperand(0))->stripPointerCasts());
-              // get the parent node of the arg node
               ArgDFNode = Leaf_HandleToDFNodeMap[ArgII];
+              // get the parent node of the arg node
               // Add mapping <intrinsic, parent node> to the node-specific map
               // the argument node must have been added to the map, orelse the
               // code could not refer to it
-              Leaf_HandleToDFNodeMap[II] = ArgDFNode;
+              Leaf_HandleToDFNodeMap[II] = ArgDFNode->getParent();
+
               IItoRemove.push_back(II);
               }
               break;
@@ -107,8 +107,11 @@ namespace {
               int numOfDim = Leaf_HandleToDFNodeMap[ArgII]->getNumOfDim();
               IntegerType* IntTy = Type::getInt32Ty(getGlobalContext());
               ConstantInt* numOfDimConstant = ConstantInt::getSigned(IntTy, (int64_t) numOfDim);
-              
-              IItoReplace.push_back(std::make_pair(II,numOfDimConstant));
+
+              // Replace the result of the intrinsic with the computed value
+              II->replaceAllUsesWith(numOfDimConstant);
+
+              IItoRemove.push_back(II);
               }
               break;
 /*********************** llvm.visc.getNodeInstanceID() ************************/
@@ -166,8 +169,12 @@ namespace {
                 assert(false && "Unable to translate this intrinsic");
               }
 
-              CallInst* CI = CallInst::Create(OpenCLFunction, Args);
-              IItoReplace.push_back(std::make_pair(II,CI));
+              // Create call instruction, insert it before the intrinsic and
+              // replace the uses of the previous instruction with the new one
+              CallInst* CI = CallInst::Create(OpenCLFunction, Args, "", II);
+              II->replaceAllUsesWith(CI);
+
+              IItoRemove.push_back(II);
               }
               break;
 /********************** llvm.visc.getNumNodeInstances() ***********************/
@@ -226,8 +233,12 @@ namespace {
                 assert(false && "Unable to translate this intrinsic");
               }
 
-              CallInst* CI = CallInst::Create(OpenCLFunction, Args);
-              IItoReplace.push_back(std::make_pair(II,CI));
+              // Create call instruction, insert it before the intrinsic and
+              // replace the uses of the previous instruction with the new one
+              CallInst* CI = CallInst::Create(OpenCLFunction, Args, "", II);
+              II->replaceAllUsesWith(CI);
+
+              IItoRemove.push_back(II);
               }
               break;
             default:
@@ -250,7 +261,8 @@ namespace {
       // using dyn_cast in order to determine if we replace with inst or value
 
 
-      //TODO: maybe leave these instructions to be removed by a later DCE pass
+      //We need to do this explicitly: DCE pass will not remove them because we
+      // have assumed theworst memory behaviour for these function calls
       for (std::vector<IntrinsicInst *>::iterator i = IItoRemove.begin();
            i != IItoRemove.end(); ++i)
         (*i)->eraseFromParent();
@@ -297,6 +309,8 @@ namespace {
     // Initiate code generation for root DFNode
     CGTVisitor->visit(Root);
 
+    //TODO: Edit module epilogue to remove the VISC intrinsic declarations
+
     return true;
   }