From 65268575c419a890052a446d28329f9e81302a05 Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Sun, 3 Jul 2011 05:26:42 +0000 Subject: [PATCH] Fix an easy fixme. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134364 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/RegisterCoalescer.cpp | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index 3b2046a5c9e..b91f92c6aa5 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -1214,12 +1214,6 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li, unsigned Dst = MI->getOperand(0).getReg(); unsigned Src = MI->getOperand(1).getReg(); - // FIXME: If "B = X" kills X, we have to move the kill back to its - // previous use. For now we just avoid the optimization in that case. - LiveInterval &SrcInt = li.getInterval(Src); - if (SrcInt.killedAt(VNI->def)) - return false; - if (!TargetRegisterInfo::isVirtualRegister(Src) || !TargetRegisterInfo::isVirtualRegister(Dst)) return false; @@ -1253,6 +1247,7 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li, // If the copies use two different value numbers of X, we cannot merge // A and B. + LiveInterval &SrcInt = li.getInterval(Src); if (SrcInt.getVNInfoAt(Other->def) != SrcInt.getVNInfoAt(VNI->def)) return false; @@ -1476,6 +1471,7 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) { if (RHSValNoAssignments.empty()) RHSValNoAssignments.push_back(-1); + SmallVector SourceRegisters; for (SmallVector::iterator I = DupCopies.begin(), E = DupCopies.end(); I != E; ++I) { MachineInstr *MI = *I; @@ -1489,11 +1485,19 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) { // X = X // and mark the X as coalesced to keep the illusion. unsigned Src = MI->getOperand(1).getReg(); + SourceRegisters.push_back(Src); MI->getOperand(0).substVirtReg(Src, 0, *tri_); markAsJoined(MI); } + // If B = X was the last use of X in a liverange, we have to shrink it now + // that B = X is gone. + for (SmallVector::iterator I = SourceRegisters.begin(), + E = SourceRegisters.end(); I != E; ++I) { + li_->shrinkToUses(&li_->getInterval(*I)); + } + // If we get here, we know that we can coalesce the live ranges. Ask the // intervals to coalesce themselves now. LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo,