diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 7b8d7c549c..c841d433c9 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -1077,9 +1077,15 @@ LowerArguments(BasicBlock *BB, SelectionDAGLowering &SDL, AI != E; ++AI,++a) if (!AI->use_empty()) { SDL.setValue(AI, Args[a]); - SDOperand Copy = - CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]); - UnorderedChains.push_back(Copy); + + if (IsOnlyUsedInOneBasicBlock(AI) == F.begin()) { + // Only used in the entry block, no need to copy it to a vreg for + // other blocks. + } else { + SDOperand Copy = + CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]); + UnorderedChains.push_back(Copy); + } } } else { // Otherwise, if any argument is only accessed in a single basic block, |