[LoopDist] Improve variable names and comments in LoopVersioning class, NFC
As with the previous patch, the goal is to turn the class into a general
loop-versioning class. This patch removes any references to loop
distribution.
llvm-svn: 240352
diff --git a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
index d21a7db..0325d26 100644
--- a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
@@ -635,10 +635,11 @@
LoopVersioning(const LoopAccessInfo &LAI, Loop *L, LoopInfo *LI,
DominatorTree *DT,
const SmallVector<int, 8> *PtrToPartition = nullptr)
- : OrigLoop(L), NonDistributedLoop(nullptr),
+ : VersionedLoop(L), NonVersionedLoop(nullptr),
PtrToPartition(PtrToPartition), LAI(LAI), LI(LI), DT(DT) {}
- /// \brief Returns true if we need memchecks to distribute the loop.
+ /// \brief Returns true if we need memchecks to disambiguate may-aliasing
+ /// accesses.
bool needsRuntimeChecks() const {
return LAI.getRuntimePointerCheck()->needsAnyChecking(PtrToPartition);
}
@@ -649,49 +650,51 @@
Instruction *FirstCheckInst;
Instruction *MemRuntimeCheck;
// Add the memcheck in the original preheader (this is empty initially).
- BasicBlock *MemCheckBB = OrigLoop->getLoopPreheader();
+ BasicBlock *MemCheckBB = VersionedLoop->getLoopPreheader();
std::tie(FirstCheckInst, MemRuntimeCheck) =
LAI.addRuntimeCheck(MemCheckBB->getTerminator(), PtrToPartition);
assert(MemRuntimeCheck && "called even though needsAnyChecking = false");
// Rename the block to make the IR more readable.
- MemCheckBB->setName(OrigLoop->getHeader()->getName() + ".ldist.memcheck");
+ MemCheckBB->setName(VersionedLoop->getHeader()->getName() +
+ ".lver.memcheck");
// Create empty preheader for the loop (and after cloning for the
- // original/nondist loop).
+ // non-versioned loop).
BasicBlock *PH =
SplitBlock(MemCheckBB, MemCheckBB->getTerminator(), DT, LI);
- PH->setName(OrigLoop->getHeader()->getName() + ".ph");
+ PH->setName(VersionedLoop->getHeader()->getName() + ".ph");
// Clone the loop including the preheader.
//
// FIXME: This does not currently preserve SimplifyLoop because the exit
// block is a join between the two loops.
- SmallVector<BasicBlock *, 8> NonDistributedLoopBlocks;
- NonDistributedLoop =
- cloneLoopWithPreheader(PH, MemCheckBB, OrigLoop, VMap, ".ldist.nondist",
- LI, DT, NonDistributedLoopBlocks);
- remapInstructionsInLoop(NonDistributedLoopBlocks, VMap);
+ SmallVector<BasicBlock *, 8> NonVersionedLoopBlocks;
+ NonVersionedLoop =
+ cloneLoopWithPreheader(PH, MemCheckBB, VersionedLoop, VMap,
+ ".lver.orig", LI, DT, NonVersionedLoopBlocks);
+ remapInstructionsInLoop(NonVersionedLoopBlocks, VMap);
// Insert the conditional branch based on the result of the memchecks.
Instruction *OrigTerm = MemCheckBB->getTerminator();
- BranchInst::Create(NonDistributedLoop->getLoopPreheader(),
- OrigLoop->getLoopPreheader(), MemRuntimeCheck, OrigTerm);
+ BranchInst::Create(NonVersionedLoop->getLoopPreheader(),
+ VersionedLoop->getLoopPreheader(), MemRuntimeCheck,
+ OrigTerm);
OrigTerm->eraseFromParent();
// The loops merge in the original exit block. This is now dominated by the
// memchecking block.
- DT->changeImmediateDominator(OrigLoop->getExitBlock(), MemCheckBB);
+ DT->changeImmediateDominator(VersionedLoop->getExitBlock(), MemCheckBB);
}
/// \brief Adds the necessary PHI nodes for the versioned loops based on the
/// loop-defined values used outside of the loop.
void addPHINodes(const SmallVectorImpl<Instruction *> &DefsUsedOutside) {
- BasicBlock *PHIBlock = OrigLoop->getExitBlock();
+ BasicBlock *PHIBlock = VersionedLoop->getExitBlock();
assert(PHIBlock && "No single successor to loop exit block");
for (auto *Inst : DefsUsedOutside) {
- auto *NonDistInst = cast<Instruction>(VMap[Inst]);
+ auto *NonVersionedLoopInst = cast<Instruction>(VMap[Inst]);
PHINode *PN;
// First see if we have a single-operand PHI with the value defined by the
@@ -704,24 +707,25 @@
}
// If not create it.
if (!PN) {
- PN = PHINode::Create(Inst->getType(), 2, Inst->getName() + ".ldist",
+ PN = PHINode::Create(Inst->getType(), 2, Inst->getName() + ".lver",
PHIBlock->begin());
for (auto *User : Inst->users())
- if (!OrigLoop->contains(cast<Instruction>(User)->getParent()))
+ if (!VersionedLoop->contains(cast<Instruction>(User)->getParent()))
User->replaceUsesOfWith(Inst, PN);
- PN->addIncoming(Inst, OrigLoop->getExitingBlock());
+ PN->addIncoming(Inst, VersionedLoop->getExitingBlock());
}
- // Add the new incoming value from the non-distributed loop.
- PN->addIncoming(NonDistInst, NonDistributedLoop->getExitingBlock());
+ // Add the new incoming value from the non-versioned loop.
+ PN->addIncoming(NonVersionedLoopInst,
+ NonVersionedLoop->getExitingBlock());
}
}
private:
/// \brief The original loop. This becomes the "versioned" one, i.e. control
/// goes if the memchecks all pass.
- Loop *OrigLoop;
+ Loop *VersionedLoop;
/// \brief The fall-back loop, i.e. if any of the memchecks fail.
- Loop *NonDistributedLoop;
+ Loop *NonVersionedLoop;
/// \brief For each memory pointer it contains the partitionId it is used in.
/// If nullptr, no partitioning is used.
@@ -730,8 +734,8 @@
/// If the pointer is used in multiple partitions the entry is set to -1.
const SmallVector<int, 8> *PtrToPartition;
- /// \brief This maps the instructions from OrigLoop to their counterpart in
- /// NonDistributedLoop.
+ /// \brief This maps the instructions from VersionedLoop to their counterpart
+ /// in NonVersionedLoop.
ValueToValueMapTy VMap;
/// \brief Analyses used.