From 1769cccfc8f248a34ab794b787752e2bdd9b21b3 Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Fri, 9 Jul 2010 01:27:19 +0000 Subject: [PATCH] Handle COPY in VirtRegRewriter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107949 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/VirtRegRewriter.cpp | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp index 15142c0ff65..d8f02495d40 100644 --- a/lib/CodeGen/VirtRegRewriter.cpp +++ b/lib/CodeGen/VirtRegRewriter.cpp @@ -2443,6 +2443,24 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs, // Also check if it's copying from an "undef", if so, we can't // eliminate this or else the undef marker is lost and it will // confuses the scavenger. This is extremely rare. + if (MI.isIdentityCopy() && !MI.getOperand(1).isUndef() && + MI.getNumOperands() == 2) { + ++NumDCE; + DEBUG(dbgs() << "Removing now-noop copy: " << MI); + SmallVector KillRegs; + InvalidateKills(MI, TRI, RegKills, KillOps, &KillRegs); + if (MO.isDead() && !KillRegs.empty()) { + // Source register or an implicit super/sub-register use is killed. + assert(TRI->regsOverlap(KillRegs[0], MI.getOperand(0).getReg())); + // Last def is now dead. + TransferDeadness(MI.getOperand(1).getReg(), RegKills, KillOps); + } + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; + Spills.disallowClobberPhysReg(VirtReg); + goto ProcessNextInst; + } unsigned Src, Dst, SrcSR, DstSR; if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) && Src == Dst && SrcSR == DstSR && @@ -2532,6 +2550,16 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs, // Check to see if this is a noop copy. If so, eliminate the // instruction before considering the dest reg to be changed. + if (MI.isIdentityCopy()) { + ++NumDCE; + DEBUG(dbgs() << "Removing now-noop copy: " << MI); + InvalidateKills(MI, TRI, RegKills, KillOps); + VRM->RemoveMachineInstrFromMaps(&MI); + MBB->erase(&MI); + Erased = true; + UpdateKills(*LastStore, TRI, RegKills, KillOps); + goto ProcessNextInst; + } { unsigned Src, Dst, SrcSR, DstSR; if (TII->isMoveInstr(MI, Src, Dst, SrcSR, DstSR) &&