From 09eeac9f5f8c21621f82f9b6598eb7e34593357e Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Thu, 11 Feb 2010 00:34:33 +0000 Subject: [PATCH] Reuse operand location when updating PHI instructions. Calling RemoveOperand is very expensive on huge PHI instructions. This makes early tail duplication run twice as fast on the Firefox JavaScript interpreter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95832 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/TailDuplication.cpp | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp index 9ab4058b19b..3223e53d5da 100644 --- a/lib/CodeGen/TailDuplication.cpp +++ b/lib/CodeGen/TailDuplication.cpp @@ -403,26 +403,45 @@ TailDuplicatePass::UpdateSuccessorsPHIs(MachineBasicBlock *FromBB, bool isDead, II->RemoveOperand(i); } } - II->RemoveOperand(Idx+1); - II->RemoveOperand(Idx); - } + } else + Idx = 0; + + // If Idx is set, the operands at Idx and Idx+1 must be removed. + // We reuse the location to avoid expensive RemoveOperand calls. + DenseMap::iterator LI=SSAUpdateVals.find(Reg); if (LI != SSAUpdateVals.end()) { // This register is defined in the tail block. for (unsigned j = 0, ee = LI->second.size(); j != ee; ++j) { MachineBasicBlock *SrcBB = LI->second[j].first; unsigned SrcReg = LI->second[j].second; - II->addOperand(MachineOperand::CreateReg(SrcReg, false)); - II->addOperand(MachineOperand::CreateMBB(SrcBB)); + if (Idx != 0) { + II->getOperand(Idx).setReg(SrcReg); + II->getOperand(Idx+1).setMBB(SrcBB); + Idx = 0; + } else { + II->addOperand(MachineOperand::CreateReg(SrcReg, false)); + II->addOperand(MachineOperand::CreateMBB(SrcBB)); + } } } else { // Live in tail block, must also be live in predecessors. for (unsigned j = 0, ee = TDBBs.size(); j != ee; ++j) { MachineBasicBlock *SrcBB = TDBBs[j]; - II->addOperand(MachineOperand::CreateReg(Reg, false)); - II->addOperand(MachineOperand::CreateMBB(SrcBB)); + if (Idx != 0) { + II->getOperand(Idx).setReg(Reg); + II->getOperand(Idx+1).setMBB(SrcBB); + Idx = 0; + } else { + II->addOperand(MachineOperand::CreateReg(Reg, false)); + II->addOperand(MachineOperand::CreateMBB(SrcBB)); + } } } + if (Idx != 0) { + II->RemoveOperand(Idx+1); + II->RemoveOperand(Idx); + } } } } -- 2.34.1