From 77ee1140a3297e6fbd6cb7cf586872af6d00d07e Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Tue, 2 Aug 2011 22:37:22 +0000 Subject: Add a BlockInfo::FirstDef field. This is either an invalid SlotIndex, or valno->def for the first value defined inside the block. PHI values are not counted as defined inside the block. The FirstDef field will be used when estimating the cost of spilling around a block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136736 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SplitKit.cpp | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'lib/CodeGen/SplitKit.cpp') diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp index 0679a619f5..45b976ca25 100644 --- a/lib/CodeGen/SplitKit.cpp +++ b/lib/CodeGen/SplitKit.cpp @@ -188,6 +188,13 @@ bool SplitAnalysis::calcLiveBlockInfo() { // LVI is the first live segment overlapping MBB. BI.LiveIn = LVI->start <= Start; + // When not live in, the first use should be a def. + if (!BI.LiveIn) { + assert(LVI->start == LVI->valno->def && "Dangling LiveRange start"); + assert(LVI->start == BI.FirstUse && "First instr should be a def"); + BI.FirstDef = BI.FirstUse; + } + // Look for gaps in the live range. BI.LiveOut = true; while (LVI->end < Stop) { @@ -197,6 +204,7 @@ bool SplitAnalysis::calcLiveBlockInfo() { BI.LastUse = LastStop; break; } + if (LastStop < LVI->start) { // There is a gap in the live range. Create duplicate entries for the // live-in snippet and the live-out snippet. @@ -210,8 +218,13 @@ bool SplitAnalysis::calcLiveBlockInfo() { // Set up BI for the live-out part. BI.LiveIn = false; BI.LiveOut = true; - BI.FirstUse = LVI->start; + BI.FirstUse = BI.FirstDef = LVI->start; } + + // A LiveRange that starts in the middle of the block must be a def. + assert(LVI->start == LVI->valno->def && "Dangling LiveRange start"); + if (!BI.FirstDef) + BI.FirstDef = LVI->start; } UseBlocks.push_back(BI); -- cgit v1.2.3-18-g5258