From 48dd5e7d44fe9c1e5fad42a76a80f6fa418a3bc3 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 30 Mar 2007 20:18:35 +0000 Subject: Bug fix for PR1279. When isDead is propagate by copy coalescing, we keep length of dead def live interval at 1 to avoid multiple def's targeting the same register. The previous patch missed a case where the source operand is live-in. In that case, remove the whole interval. llvm-svn: 35512 --- llvm/lib/CodeGen/LiveIntervalAnalysis.cpp | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'llvm/lib/CodeGen/LiveIntervalAnalysis.cpp') diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp index ff7b555d563..bc4f6016f36 100644 --- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -915,6 +915,7 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI, // Check if it is necessary to propagate "isDead" property before intervals // are joined. + MachineBasicBlock *CopyBB = CopyMI->getParent(); MachineOperand *mopd = CopyMI->findRegisterDefOperand(DstReg); bool isDead = mopd->isDead(); bool isShorten = false; @@ -941,9 +942,15 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI, isShorten = true; RemoveStart = getDefIndex(getInstructionIndex(LastUse)); RemoveEnd = SrcEnd; - } else if (RemoveStart > 0) - // A dead def should have a single cycle interval. - ++RemoveStart; + } else { + MachineInstr *SrcMI = getInstructionFromIndex(SrcStart); + if (SrcMI) { + MachineOperand *mops = SrcMI->findRegisterDefOperand(SrcReg); + if (mops) + // A dead def should have a single cycle interval. + ++RemoveStart; + } + } } } @@ -959,7 +966,6 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI, LiveVariables::VarInfo& dvi = lv_->getVarInfo(repDstReg); // Is the value used in the current BB or any immediate successroe BB? - MachineBasicBlock *CopyBB = CopyMI->getParent(); if (dvi.UsedBlocks[CopyBB->getNumber()]) goto TryJoin; for (MachineBasicBlock::succ_iterator SI = CopyBB->succ_begin(), @@ -1018,7 +1024,6 @@ TryJoin: if (SrcMI) { MachineOperand *mops = SrcMI->findRegisterDefOperand(SrcReg); if (mops) - // FIXME: mops == NULL means SrcMI defines a subregister? mops->setIsDead(); } } -- cgit v1.2.3