[llvm] r224461 - RegisterCoalescer: Fix stripCopies() picking up main range instead of subregister range
Matthias Braun
matze at braunis.de
Wed Dec 17 13:25:21 PST 2014
Author: matze
Date: Wed Dec 17 15:25:20 2014
New Revision: 224461
URL: http://llvm.org/viewvc/llvm-project?rev=224461&view=rev
Log:
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.
Modified:
llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp
Modified: llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp?rev=224461&r1=224460&r2=224461&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp Wed Dec 17 15:25:20 2014
@@ -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<Val, 8> 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<VNInfo*> &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(con
}
/// 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, J
// %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(SmallPtrSetIm
}
}
-void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, LiveRange &RRange,
+void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, unsigned LMask,
+ LiveRange &RRange, unsigned RMask,
const CoalescerPair &CP) {
SmallVector<VNInfo*, 16> 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
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::mergeSubRangeInt
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::mergeSubRangeInt
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(Coa
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(Coa
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(Coa
<< " => " << format("%04X", RMask) << "\n");
}
- mergeSubRangeInto(LHS, R, RMask, CP);
+ mergeSubRangeInto(LHS, R, RMask, R.LaneMask, CP);
}
}
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