From 1dabb68ab45cb05a2c50e9a6f18f60cd3d7105f4 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 1 Nov 2006 22:39:30 +0000 Subject: [PATCH] Clean up. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31359 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp index 0e63817e23b..7704a531aff 100644 --- a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp +++ b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp @@ -719,7 +719,14 @@ int BURegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { return SethiUllmanNumber; unsigned Opc = SU->Node->getOpcode(); - if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg) + if (Opc == ISD::CopyFromReg && !isCopyFromLiveIn(SU)) + // CopyFromReg should be close to its def because it restricts allocation + // choices. But if it is a livein then perhaps we want it closer to the + // uses so it can be coalesced. + SethiUllmanNumber = INT_MIN + 10; + else if (Opc == ISD::TokenFactor || Opc == ISD::CopyToReg) + // CopyToReg should be close to its uses to facilitate coalescing and avoid + // spilling. SethiUllmanNumber = INT_MAX - 10; else if (SU->NumSuccsLeft == 0) // If SU does not have a use, i.e. it doesn't produce a value that would @@ -727,10 +734,9 @@ int BURegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { // Give it a small SethiUllman number so it will be scheduled right before its // predecessors that it doesn't lengthen their live ranges. SethiUllmanNumber = INT_MIN + 10; - // FIXME: remove this else if? It seems to reduce register spills but often - // ends up increasing runtime. Need to investigate. - else if (SU->NumPredsLeft == 0 && - (Opc != ISD::CopyFromReg || isCopyFromLiveIn(SU))) + else if (SU->NumPredsLeft == 0) + // If SU does not have a def, schedule it close to its uses because it does + // not lengthen any live ranges. SethiUllmanNumber = INT_MAX - 10; else { int Extra = 0; -- 2.34.1