From 876e7172eed7e37f4ebf97a432dea7223b85ede5 Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Fri, 20 Feb 2015 23:43:14 +0000 Subject: [PATCH] LiveRangeCalc: Don't start liveranges of PHI instruction at the block begin. Summary: Letting them begin at the PHI instruction slightly simplifies the code but more importantly avoids breaking the assumption that live ranges starting at the block begin are also live at the end of the predecessor blocks. The MachineVerifier checks that but was apparently never run in the few instances where liveranges are calculated for machine-SSA functions. Reviewers: qcolombet Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D7779 llvm-svn: 230093 --- llvm/lib/CodeGen/LiveRangeCalc.cpp | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/llvm/lib/CodeGen/LiveRangeCalc.cpp b/llvm/lib/CodeGen/LiveRangeCalc.cpp index a07c3a3..d804b39 100644 --- a/llvm/lib/CodeGen/LiveRangeCalc.cpp +++ b/llvm/lib/CodeGen/LiveRangeCalc.cpp @@ -43,11 +43,8 @@ void LiveRangeCalc::reset(const MachineFunction *mf, static void createDeadDef(SlotIndexes &Indexes, VNInfo::Allocator &Alloc, LiveRange &LR, const MachineOperand &MO) { const MachineInstr *MI = MO.getParent(); - SlotIndex DefIdx; - if (MI->isPHI()) - DefIdx = Indexes.getMBBStartIdx(MI->getParent()); - else - DefIdx = Indexes.getInstructionIndex(MI).getRegSlot(MO.isEarlyClobber()); + SlotIndex DefIdx = + Indexes.getInstructionIndex(MI).getRegSlot(MO.isEarlyClobber()); // Create the def in LR. This may find an existing def. LR.createDeadDef(DefIdx, Alloc); -- 2.7.4