From d592a28ca1506f2ccd6384679d87cce4b4fd874a Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 28 Mar 2007 01:30:37 +0000 Subject: [PATCH] Fix for PR1279. Dead def has a live interval of length 1. Copy coalescing should not violate that. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35396 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LiveIntervalAnalysis.cpp | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index 38ada30ad74..eb3ac31998a 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -935,9 +935,9 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI, // The instruction which defines the src is only truly dead if there are // no intermediate uses and there isn't a use beyond the copy. // FIXME: find the last use, mark is kill and shorten the live range. - if (SrcEnd > getDefIndex(CopyIdx)) + if (SrcEnd > getDefIndex(CopyIdx)) { isDead = false; - else { + } else { MachineOperand *MOU; MachineInstr *LastUse= lastRegisterUse(repSrcReg, SrcStart, CopyIdx, MOU); if (LastUse) { @@ -947,7 +947,9 @@ 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; } } -- 2.34.1