From a1a68905b51e292008309cdacb765642b1a33a25 Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Wed, 17 Dec 2014 21:25:20 +0000 Subject: [PATCH] RegisterCoalescer: Fix stripCopies() picking up main range instead of subregister range This fixes a problem where stripCopies() would switch to values in the main liverange when it crossed a copy instruction. However when joining subranges we need to stay in the respective subregister ranges. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224461 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/RegisterCoalescer.cpp | 128 ++++++++++++++++++------------ 1 file changed, 78 insertions(+), 50 deletions(-) diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index a3b68829a30..416f95bad7d 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -159,12 +159,16 @@ namespace { /// Add the LiveRange @p ToMerge as a subregister liverange of @p LI. /// Subranges in @p LI which only partially interfere with the desired /// LaneMask are split as necessary. + /// @p DestLaneMask are the lanes that @p ToMerge will end up in after the + /// merge, @p PrevLaneMask the ones it currently occupies. void mergeSubRangeInto(LiveInterval &LI, const LiveRange &ToMerge, - unsigned LaneMask, CoalescerPair &CP); + unsigned DstLaneMask, unsigned PrevLaneMask, + CoalescerPair &CP); /// Join the liveranges of two subregisters. Joins @p RRange into /// @p LRange, @p RRange may be invalid afterwards. - void joinSubRegRanges(LiveRange &LRange, LiveRange &RRange, + void joinSubRegRanges(LiveRange &LRange, unsigned LMask, + LiveRange &RRange, unsigned RMask, const CoalescerPair &CP); /// We found a non-trivially-coalescable copy. If @@ -1503,6 +1507,8 @@ class JoinVals { /// (Main) register we work on. const unsigned Reg; + /// When coalescing a subregister range this is the LaneMask in Reg. + unsigned SubRegMask; /// This is true when joining sub register ranges, false when joining main /// ranges. const bool SubRangeJoin; @@ -1603,7 +1609,8 @@ class JoinVals { SmallVector Vals; unsigned computeWriteLanes(const MachineInstr *DefMI, bool &Redef) const; - VNInfo *stripCopies(VNInfo *VNI) const; + VNInfo *stripCopies(VNInfo *VNI, unsigned LaneMask, unsigned &Reg) const; + bool valuesIdentical(VNInfo *Val0, VNInfo *Val1, const JoinVals &Other) const; ConflictResolution analyzeValue(unsigned ValNo, JoinVals &Other); void computeAssignment(unsigned ValNo, JoinVals &Other); bool taintExtent(unsigned, unsigned, JoinVals&, @@ -1615,9 +1622,9 @@ public: JoinVals(LiveRange &LR, unsigned Reg, unsigned subIdx, SmallVectorImpl &newVNInfo, const CoalescerPair &cp, LiveIntervals *lis, - const TargetRegisterInfo *tri, bool SubRangeJoin, - bool TrackSubRegLiveness) - : LR(LR), Reg(Reg), SubRangeJoin(SubRangeJoin), + const TargetRegisterInfo *tri, unsigned SubRegMask, + bool SubRangeJoin, bool TrackSubRegLiveness) + : LR(LR), Reg(Reg), SubRegMask(SubRegMask), SubRangeJoin(SubRangeJoin), TrackSubRegLiveness(TrackSubRegLiveness), SubIdx(subIdx), NewVNInfo(newVNInfo), CP(cp), LIS(lis), Indexes(LIS->getSlotIndexes()), TRI(tri), Assignments(LR.getNumValNums(), -1), @@ -1673,23 +1680,58 @@ unsigned JoinVals::computeWriteLanes(const MachineInstr *DefMI, bool &Redef) } /// Find the ultimate value that VNI was copied from. -VNInfo *JoinVals::stripCopies(VNInfo *VNI) const { +VNInfo *JoinVals::stripCopies(VNInfo *VNI, unsigned LaneMask, unsigned &Reg) + const { while (!VNI->isPHIDef()) { - MachineInstr *MI = Indexes->getInstructionFromIndex(VNI->def); + SlotIndex Def = VNI->def; + MachineInstr *MI = Indexes->getInstructionFromIndex(Def); assert(MI && "No defining instruction"); if (!MI->isFullCopy()) + return VNI; + unsigned SrcReg = MI->getOperand(1).getReg(); + if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) + return VNI; + + const LiveInterval &LI = LIS->getInterval(SrcReg); + VNInfo *ValueIn; + // No subrange involved. + if (LaneMask == 0 || !LI.hasSubRanges()) { + LiveQueryResult LRQ = LI.Query(Def); + ValueIn = LRQ.valueIn(); + } else { + // Query subranges. Pick the first matching one. + ValueIn = nullptr; + for (const LiveInterval::SubRange &S : LI.subranges()) { + if ((S.LaneMask & LaneMask) == 0) + continue; + LiveQueryResult LRQ = S.Query(Def); + ValueIn = LRQ.valueIn(); + break; + } + } + if (ValueIn == nullptr) break; - unsigned Reg = MI->getOperand(1).getReg(); - if (!TargetRegisterInfo::isVirtualRegister(Reg)) - break; - LiveQueryResult LRQ = LIS->getInterval(Reg).Query(VNI->def); - if (!LRQ.valueIn()) - break; - VNI = LRQ.valueIn(); + VNI = ValueIn; + Reg = SrcReg; } return VNI; } +bool JoinVals::valuesIdentical(VNInfo *Value0, VNInfo *Value1, + const JoinVals &Other) const { + unsigned Reg0 = Reg; + VNInfo *Stripped0 = stripCopies(Value0, SubRegMask, Reg0); + unsigned Reg1 = Other.Reg; + VNInfo *Stripped1 = stripCopies(Value1, Other.SubRegMask, Reg1); + if (Stripped0 == Stripped1) + return true; + + // Special case: when merging subranges one of the ranges is actually a copy, + // so we can't simply compare VNInfos but have to resort to comparing + // position and register of the Def. + return Stripped0->def == Stripped1->def && Reg0 == Reg1; +} + /// Analyze ValNo in this live range, and set all fields of Vals[ValNo]. /// Return a conflict resolution when possible, but leave the hard cases as /// CR_Unresolved. @@ -1849,26 +1891,9 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) { // %other = COPY %ext // %this = COPY %ext <-- Erase this copy // - if (DefMI->isFullCopy() && !CP.isPartial()) { - VNInfo *TVNI = stripCopies(VNI); - VNInfo *OVNI = stripCopies(V.OtherVNI); - // Map our subrange values to main range as stripCopies() follows the main - // ranges. - if (SubRangeJoin && TVNI != OVNI) { - if (TVNI == VNI) { - LiveInterval &LI = LIS->getInterval(Reg); - TVNI = LI.getVNInfoAt(TVNI->def); - } - if (OVNI == V.OtherVNI) { - LiveInterval &LI = LIS->getInterval(Other.Reg); - OVNI = LI.getVNInfoAt(OVNI->def); - } - } - - if (TVNI == OVNI) - return CR_Erase; - } - + if (DefMI->isFullCopy() && !CP.isPartial() + && valuesIdentical(VNI, V.OtherVNI, Other)) + return CR_Erase; // If the lanes written by this instruction were all undef in OtherVNI, it is // still safe to join the live ranges. This can't be done with a simple value @@ -2277,13 +2302,14 @@ void JoinVals::eraseInstrs(SmallPtrSetImpl &ErasedInstrs, } } -void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, LiveRange &RRange, +void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, unsigned LMask, + LiveRange &RRange, unsigned RMask, const CoalescerPair &CP) { SmallVector NewVNInfo; JoinVals RHSVals(RRange, CP.getSrcReg(), CP.getSrcIdx(), - NewVNInfo, CP, LIS, TRI, true, true); + NewVNInfo, CP, LIS, TRI, LMask, true, true); JoinVals LHSVals(LRange, CP.getDstReg(), CP.getDstIdx(), - NewVNInfo, CP, LIS, TRI, true, true); + NewVNInfo, CP, LIS, TRI, RMask, true, true); /// Compute NewVNInfo and resolve conflicts (see also joinVirtRegs()) /// Conflicts should already be resolved so the mapping/resolution should @@ -2321,13 +2347,14 @@ void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, LiveRange &RRange, void RegisterCoalescer::mergeSubRangeInto(LiveInterval &LI, const LiveRange &ToMerge, - unsigned LaneMask, + unsigned DstLaneMask, + unsigned PrevLaneMask, CoalescerPair &CP) { BumpPtrAllocator &Allocator = LIS->getVNInfoAllocator(); for (LiveInterval::SubRange &R : LI.subranges()) { unsigned RMask = R.LaneMask; // LaneMask of subregisters common to subrange R and ToMerge. - unsigned Common = RMask & LaneMask; + unsigned Common = RMask & DstLaneMask; // There is nothing to do without common subregs. if (Common == 0) continue; @@ -2335,7 +2362,7 @@ void RegisterCoalescer::mergeSubRangeInto(LiveInterval &LI, DEBUG(dbgs() << format("\t\tCopy+Merge %04X into %04X\n", RMask, Common)); // LaneMask of subregisters contained in the R range but not in ToMerge, // they have to split into their own subrange. - unsigned LRest = RMask & ~LaneMask; + unsigned LRest = RMask & ~DstLaneMask; LiveInterval::SubRange *CommonRange; if (LRest != 0) { R.LaneMask = LRest; @@ -2348,13 +2375,14 @@ void RegisterCoalescer::mergeSubRangeInto(LiveInterval &LI, CommonRange = &R; } LiveRange RangeCopy(ToMerge, Allocator); - joinSubRegRanges(*CommonRange, RangeCopy, CP); - LaneMask &= ~RMask; + joinSubRegRanges(*CommonRange, CommonRange->LaneMask, RangeCopy, + PrevLaneMask, CP); + DstLaneMask &= ~RMask; } - if (LaneMask != 0) { - DEBUG(dbgs() << format("\t\tNew Lane %04X\n", LaneMask)); - LI.createSubRangeFrom(Allocator, LaneMask, ToMerge); + if (DstLaneMask != 0) { + DEBUG(dbgs() << format("\t\tNew Lane %04X\n", DstLaneMask)); + LI.createSubRangeFrom(Allocator, DstLaneMask, ToMerge); } } @@ -2364,9 +2392,9 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) { LiveInterval &LHS = LIS->getInterval(CP.getDstReg()); bool TrackSubRegLiveness = MRI->tracksSubRegLiveness(); JoinVals RHSVals(RHS, CP.getSrcReg(), CP.getSrcIdx(), NewVNInfo, CP, LIS, TRI, - false, TrackSubRegLiveness); + 0, false, TrackSubRegLiveness); JoinVals LHSVals(LHS, CP.getDstReg(), CP.getDstIdx(), NewVNInfo, CP, LIS, TRI, - false, TrackSubRegLiveness); + 0, false, TrackSubRegLiveness); DEBUG(dbgs() << "\t\tRHS = " << RHS << "\n\t\tLHS = " << LHS @@ -2411,7 +2439,7 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) { DEBUG(dbgs() << "\t\tRHS Mask: " << format("%04X", Mask) << "\n"); - mergeSubRangeInto(LHS, RHS, Mask, CP); + mergeSubRangeInto(LHS, RHS, Mask, 0, CP); } else { // Pair up subranges and merge. for (LiveInterval::SubRange &R : RHS.subranges()) { @@ -2425,7 +2453,7 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) { << " => " << format("%04X", RMask) << "\n"); } - mergeSubRangeInto(LHS, R, RMask, CP); + mergeSubRangeInto(LHS, R, RMask, R.LaneMask, CP); } } -- 2.34.1