From 7511abd5c1c6a8adcd7609cca53446613310a6d9 Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Mon, 4 Apr 2016 21:23:46 +0000 Subject: [PATCH] MachineScheduler: Ignore COPYs with undef/dead op in CopyConstrain mutation. There is no problem with the code today, but the fix will avoid a crash in test/CodeGen/AMDGPU/subreg-coalescer-undef-use.ll once the DetectDeadLanes pass is added. llvm-svn: 265351 --- llvm/lib/CodeGen/MachineScheduler.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp index 18933a9..9a7cae6 100644 --- a/llvm/lib/CodeGen/MachineScheduler.cpp +++ b/llvm/lib/CodeGen/MachineScheduler.cpp @@ -1580,12 +1580,14 @@ void CopyConstrain::constrainLocalCopy(SUnit *CopySU, ScheduleDAGMILive *DAG) { MachineInstr *Copy = CopySU->getInstr(); // Check for pure vreg copies. - unsigned SrcReg = Copy->getOperand(1).getReg(); - if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) + const MachineOperand &SrcOp = Copy->getOperand(1); + unsigned SrcReg = SrcOp.getReg(); + if (!TargetRegisterInfo::isVirtualRegister(SrcReg) || !SrcOp.readsReg()) return; - unsigned DstReg = Copy->getOperand(0).getReg(); - if (!TargetRegisterInfo::isVirtualRegister(DstReg)) + const MachineOperand &DstOp = Copy->getOperand(0); + unsigned DstReg = DstOp.getReg(); + if (!TargetRegisterInfo::isVirtualRegister(DstReg) || DstOp.isDead()) return; // Check if either the dest or source is local. If it's live across a back -- 2.7.4