From f6ff51fc62f312e0251c663c8d527559af1bf8ed Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Fri, 9 Mar 2018 23:36:58 +0000 Subject: [TwoAddressInstructionPass] Improve tryInstructionCommute of X86 FMA and vpternlog instructions These instructions have 3 operands that can be commuted. The first commute we find may not be the best. So we should keep searching if we performed an aggressive commute. There may still be an operand that is killed or a physical register constraint that might be better. Differential Revision: https://reviews.llvm.org/D44324 llvm-svn: 327188 --- llvm/lib/CodeGen/TwoAddressInstructionPass.cpp | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) (limited to 'llvm/lib/CodeGen/TwoAddressInstructionPass.cpp') diff --git a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp index 774b76f84b7..539f8486192 100644 --- a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -1205,6 +1205,7 @@ bool TwoAddressInstructionPass::tryInstructionCommute(MachineInstr *MI, if (!MI->isCommutable()) return false; + bool MadeChange = false; unsigned DstOpReg = MI->getOperand(DstOpIdx).getReg(); unsigned BaseOpReg = MI->getOperand(BaseOpIdx).getReg(); unsigned OpsNum = MI->getDesc().getNumOperands(); @@ -1223,8 +1224,8 @@ bool TwoAddressInstructionPass::tryInstructionCommute(MachineInstr *MI, // If OtherOp dies but BaseOp does not, swap the OtherOp and BaseOp // operands. This makes the live ranges of DstOp and OtherOp joinable. - bool DoCommute = - !BaseOpKilled && isKilled(*MI, OtherOpReg, MRI, TII, LIS, false); + bool OtherOpKilled = isKilled(*MI, OtherOpReg, MRI, TII, LIS, false); + bool DoCommute = !BaseOpKilled && OtherOpKilled; if (!DoCommute && isProfitableToCommute(DstOpReg, BaseOpReg, OtherOpReg, MI, Dist)) { @@ -1235,13 +1236,21 @@ bool TwoAddressInstructionPass::tryInstructionCommute(MachineInstr *MI, // If it's profitable to commute, try to do so. if (DoCommute && commuteInstruction(MI, DstOpIdx, BaseOpIdx, OtherOpIdx, Dist)) { + MadeChange = true; ++NumCommuted; - if (AggressiveCommute) + if (AggressiveCommute) { ++NumAggrCommuted; - return true; + // There might be more than two commutable operands, update BaseOp and + // continue scanning. + BaseOpReg = OtherOpReg; + BaseOpKilled = OtherOpKilled; + continue; + } + // If this was a commute based on kill, we won't do better continuing. + return MadeChange; } } - return false; + return MadeChange; } /// For the case where an instruction has a single pair of tied register -- cgit v1.2.3