[llvm] r303850 - [GVNSink] GVNSink pass
James Molloy via llvm-commits
llvm-commits at lists.llvm.org
Fri May 26 23:22:03 PDT 2017
Hi,
Hal; gah yes; the patch commit message was taken from the phab review that
was ongoing for ages and I didn't remove that paragraph.
Zachary- sorry about that. I'm on vacation at the moment so don't have
access to any Dev machine. The pass is turned off, so I presume the only
way to get this assert currently is in gvnsink's own regression tests?
I suppose the options are: quick switch to std::sort to pacify the bot and
I'll ensure the code is actually correct later, xfail the tests or revert.
Apologies, if I'd seen a buildbot failure for this I'd have fixed it on
Thursday.
James
On Sat, 27 May 2017 at 03:35, Zachary Turner via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Is this being addressed?
>
> This asserts on MSVC in a debug build because it uses debug iterators that
> check this kind of thing.
>
>
> On Thu, May 25, 2017 at 9:05 AM Benjamin Kramer via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> On Thu, May 25, 2017 at 2:51 PM, James Molloy via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>> > Author: jamesm
>> > Date: Thu May 25 07:51:11 2017
>> > New Revision: 303850
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=303850&view=rev
>> > Log:
>> > [GVNSink] GVNSink pass
>> >
>> > This patch provides an initial prototype for a pass that sinks
>> instructions based on GVN information, similar to GVNHoist. It is not yet
>> ready for commiting but I've uploaded it to gather some initial thoughts.
>> >
>> > This pass attempts to sink instructions into successors, reducing static
>> > instruction count and enabling if-conversion.
>> > We use a variant of global value numbering to decide what can be sunk.
>> > Consider:
>> >
>> > [ %a1 = add i32 %b, 1 ] [ %c1 = add i32 %d, 1 ]
>> > [ %a2 = xor i32 %a1, 1 ] [ %c2 = xor i32 %c1, 1 ]
>> > \ /
>> > [ %e = phi i32 %a2, %c2 ]
>> > [ add i32 %e, 4 ]
>> >
>> > GVN would number %a1 and %c1 differently because they compute different
>> > results - the VN of an instruction is a function of its opcode and the
>> > transitive closure of its operands. This is the key property for
>> hoisting
>> > and CSE.
>> >
>> > What we want when sinking however is for a numbering that is a function
>> of
>> > the *uses* of an instruction, which allows us to answer the question
>> "if I
>> > replace %a1 with %c1, will it contribute in an equivalent way to all
>> > successive instructions?". The (new) PostValueTable class in GVN
>> provides this
>> > mapping.
>> >
>> > This pass has some shown really impressive improvements especially for
>> codesize already on internal benchmarks, so I have high hopes it can
>> replace all the sinking logic in SimplifyCFG.
>> >
>> > Differential revision: https://reviews.llvm.org/D24805
>> >
>> > Added:
>> > llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp
>> > llvm/trunk/test/Transforms/GVNSink/
>> > llvm/trunk/test/Transforms/GVNSink/dither.ll
>> > llvm/trunk/test/Transforms/GVNSink/indirect-call.ll
>> > llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll
>> > llvm/trunk/test/Transforms/GVNSink/struct.ll
>> > Modified:
>> > llvm/trunk/include/llvm/InitializePasses.h
>> > llvm/trunk/include/llvm/Transforms/Scalar.h
>> > llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
>> > llvm/trunk/include/llvm/Transforms/Utils/Local.h
>> > llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
>> > llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
>> > llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
>> > llvm/trunk/lib/Transforms/Utils/Local.cpp
>> > llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>> >
>> > Modified: llvm/trunk/include/llvm/InitializePasses.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/include/llvm/InitializePasses.h (original)
>> > +++ llvm/trunk/include/llvm/InitializePasses.h Thu May 25 07:51:11 2017
>> > @@ -144,6 +144,7 @@ void initializeGCMachineCodeAnalysisPass
>> > void initializeGCModuleInfoPass(PassRegistry&);
>> > void initializeGCOVProfilerLegacyPassPass(PassRegistry&);
>> > void initializeGVNHoistLegacyPassPass(PassRegistry&);
>> > +void initializeGVNSinkLegacyPassPass(PassRegistry&);
>> > void initializeGVNLegacyPassPass(PassRegistry&);
>> > void initializeGlobalDCELegacyPassPass(PassRegistry&);
>> > void initializeGlobalMergePass(PassRegistry&);
>> >
>> > Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
>> > +++ llvm/trunk/include/llvm/Transforms/Scalar.h Thu May 25 07:51:11 2017
>> > @@ -356,6 +356,13 @@ FunctionPass *createGVNHoistPass();
>> >
>> >
>> //===----------------------------------------------------------------------===//
>> > //
>> > +// GVNSink - This pass uses an "inverted" value numbering to decide the
>> > +// similarity of expressions and sinks similar expressions into
>> successors.
>> > +//
>> > +FunctionPass *createGVNSinkPass();
>> > +
>> >
>> +//===----------------------------------------------------------------------===//
>> > +//
>> > // MergedLoadStoreMotion - This pass merges loads and stores in
>> diamonds. Loads
>> > // are hoisted into the header, while stores sink into the footer.
>> > //
>> >
>> > Modified: llvm/trunk/include/llvm/Transforms/Scalar/GVN.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar/GVN.h?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/include/llvm/Transforms/Scalar/GVN.h (original)
>> > +++ llvm/trunk/include/llvm/Transforms/Scalar/GVN.h Thu May 25 07:51:11
>> 2017
>> > @@ -238,7 +238,12 @@ struct GVNHoistPass : PassInfoMixin<GVNH
>> > /// \brief Run the pass over the function.
>> > PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
>> > };
>> > -
>> > +/// \brief Uses an "inverted" value numbering to decide the similarity
>> of
>> > +/// expressions and sinks similar expressions into successors.
>> > +struct GVNSinkPass : PassInfoMixin<GVNSinkPass> {
>> > + /// \brief Run the pass over the function.
>> > + PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
>> > +};
>> > }
>> >
>> > #endif
>> >
>> > Modified: llvm/trunk/include/llvm/Transforms/Utils/Local.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/Local.h?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
>> > +++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Thu May 25
>> 07:51:11 2017
>> > @@ -410,6 +410,14 @@ bool recognizeBSwapOrBitReverseIdiom(
>> > void maybeMarkSanitizerLibraryCallNoBuiltin(CallInst *CI,
>> > const TargetLibraryInfo
>> *TLI);
>> >
>> >
>> +//===----------------------------------------------------------------------===//
>> > +// Transform predicates
>> > +//
>> > +
>> > +/// Given an instruction, is it legal to set operand OpIdx to a
>> non-constant
>> > +/// value?
>> > +bool canReplaceOperandWithVariable(const Instruction *I, unsigned
>> OpIdx);
>> > +
>> > } // End llvm namespace
>> >
>> > #endif
>> >
>> > Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
>> > +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu May 25
>> 07:51:11 2017
>> > @@ -155,6 +155,10 @@ static cl::opt<bool>
>> > cl::Hidden,
>> > cl::desc("Enable the simple loop unswitch
>> pass."));
>> >
>> > +static cl::opt<bool> EnableGVNSink(
>> > + "enable-gvn-sink", cl::init(false), cl::Hidden,
>> > + cl::desc("Enable the GVN sinking pass (default = on)"));
>> > +
>> > PassManagerBuilder::PassManagerBuilder() {
>> > OptLevel = 2;
>> > SizeLevel = 0;
>> > @@ -307,6 +311,11 @@ void PassManagerBuilder::addFunctionSimp
>> > MPM.add(createEarlyCSEPass()); // Catch trivial
>> redundancies
>> > if (EnableGVNHoist)
>> > MPM.add(createGVNHoistPass());
>> > + if (EnableGVNSink) {
>> > + MPM.add(createGVNSinkPass());
>> > + MPM.add(createCFGSimplificationPass());
>> > + }
>> > +
>> > // Speculative execution if the target has divergent branches;
>> otherwise nop.
>> > MPM.add(createSpeculativeExecutionIfHasBranchDivergencePass());
>> > MPM.add(createJumpThreadingPass()); // Thread jumps.
>> >
>> > Modified: llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt (original)
>> > +++ llvm/trunk/lib/Transforms/Scalar/CMakeLists.txt Thu May 25 07:51:11
>> 2017
>> > @@ -13,6 +13,7 @@ add_llvm_library(LLVMScalarOpts
>> > GuardWidening.cpp
>> > GVN.cpp
>> > GVNHoist.cpp
>> > + GVNSink.cpp
>> > IVUsersPrinter.cpp
>> > InductiveRangeCheckElimination.cpp
>> > IndVarSimplify.cpp
>> >
>> > Added: llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp?rev=303850&view=auto
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp (added)
>> > +++ llvm/trunk/lib/Transforms/Scalar/GVNSink.cpp Thu May 25 07:51:11
>> 2017
>> > @@ -0,0 +1,870 @@
>> > +//===- GVNSink.cpp - sink expressions into successors
>> -------------------===//
>> > +//
>> > +// The LLVM Compiler Infrastructure
>> > +//
>> > +// This file is distributed under the University of Illinois Open
>> Source
>> > +// License. See LICENSE.TXT for details.
>> > +//
>> >
>> +//===----------------------------------------------------------------------===//
>> > +//
>> > +/// \file GVNSink.cpp
>> > +/// This pass attempts to sink instructions into successors, reducing
>> static
>> > +/// instruction count and enabling if-conversion.
>> > +///
>> > +/// We use a variant of global value numbering to decide what can be
>> sunk.
>> > +/// Consider:
>> > +///
>> > +/// [ %a1 = add i32 %b, 1 ] [ %c1 = add i32 %d, 1 ]
>> > +/// [ %a2 = xor i32 %a1, 1 ] [ %c2 = xor i32 %c1, 1 ]
>> > +/// \ /
>> > +/// [ %e = phi i32 %a2, %c2 ]
>> > +/// [ add i32 %e, 4 ]
>> > +///
>> > +///
>> > +/// GVN would number %a1 and %c1 differently because they compute
>> different
>> > +/// results - the VN of an instruction is a function of its opcode and
>> the
>> > +/// transitive closure of its operands. This is the key property for
>> hoisting
>> > +/// and CSE.
>> > +///
>> > +/// What we want when sinking however is for a numbering that is a
>> function of
>> > +/// the *uses* of an instruction, which allows us to answer the
>> question "if I
>> > +/// replace %a1 with %c1, will it contribute in an equivalent way to
>> all
>> > +/// successive instructions?". The PostValueTable class in GVN
>> provides this
>> > +/// mapping.
>> > +///
>> >
>> +//===----------------------------------------------------------------------===//
>> > +
>> > +#include "llvm/ADT/DenseMap.h"
>> > +#include "llvm/ADT/DenseMapInfo.h"
>> > +#include "llvm/ADT/DenseSet.h"
>> > +#include "llvm/ADT/Hashing.h"
>> > +#include "llvm/ADT/Optional.h"
>> > +#include "llvm/ADT/PostOrderIterator.h"
>> > +#include "llvm/ADT/SCCIterator.h"
>> > +#include "llvm/ADT/SmallPtrSet.h"
>> > +#include "llvm/ADT/Statistic.h"
>> > +#include "llvm/ADT/StringExtras.h"
>> > +#include "llvm/Analysis/GlobalsModRef.h"
>> > +#include "llvm/Analysis/MemorySSA.h"
>> > +#include "llvm/Analysis/PostDominators.h"
>> > +#include "llvm/Analysis/TargetTransformInfo.h"
>> > +#include "llvm/Analysis/ValueTracking.h"
>> > +#include "llvm/IR/Instructions.h"
>> > +#include "llvm/IR/Verifier.h"
>> > +#include "llvm/Support/MathExtras.h"
>> > +#include "llvm/Transforms/Scalar.h"
>> > +#include "llvm/Transforms/Scalar/GVN.h"
>> > +#include "llvm/Transforms/Scalar/GVNExpression.h"
>> > +#include "llvm/Transforms/Utils/BasicBlockUtils.h"
>> > +#include "llvm/Transforms/Utils/Local.h"
>> > +#include <unordered_set>
>> > +using namespace llvm;
>> > +
>> > +#define DEBUG_TYPE "gvn-sink"
>> > +
>> > +STATISTIC(NumRemoved, "Number of instructions removed");
>> > +
>> > +namespace {
>> > +
>> > +static bool isMemoryInst(const Instruction *I) {
>> > + return isa<LoadInst>(I) || isa<StoreInst>(I) ||
>> > + (isa<InvokeInst>(I) &&
>> !cast<InvokeInst>(I)->doesNotAccessMemory()) ||
>> > + (isa<CallInst>(I) &&
>> !cast<CallInst>(I)->doesNotAccessMemory());
>> > +}
>> > +
>> > +/// Iterates through instructions in a set of blocks in reverse order
>> from the
>> > +/// first non-terminator. For example (assume all blocks have size n):
>> > +/// LockstepReverseIterator I([B1, B2, B3]);
>> > +/// *I-- = [B1[n], B2[n], B3[n]];
>> > +/// *I-- = [B1[n-1], B2[n-1], B3[n-1]];
>> > +/// *I-- = [B1[n-2], B2[n-2], B3[n-2]];
>> > +/// ...
>> > +///
>> > +/// It continues until all blocks have been exhausted. Use \c
>> getActiveBlocks()
>> > +/// to
>> > +/// determine which blocks are still going and the order they appear
>> in the
>> > +/// list returned by operator*.
>> > +class LockstepReverseIterator {
>> > + ArrayRef<BasicBlock *> Blocks;
>> > + SmallPtrSet<BasicBlock *, 4> ActiveBlocks;
>> > + SmallVector<Instruction *, 4> Insts;
>> > + bool Fail;
>> > +
>> > +public:
>> > + LockstepReverseIterator(ArrayRef<BasicBlock *> Blocks) :
>> Blocks(Blocks) {
>> > + reset();
>> > + }
>> > +
>> > + void reset() {
>> > + Fail = false;
>> > + ActiveBlocks.clear();
>> > + for (BasicBlock *BB : Blocks)
>> > + ActiveBlocks.insert(BB);
>> > + Insts.clear();
>> > + for (BasicBlock *BB : Blocks) {
>> > + if (BB->size() <= 1) {
>> > + // Block wasn't big enough - only contained a terminator.
>> > + ActiveBlocks.erase(BB);
>> > + continue;
>> > + }
>> > + Insts.push_back(BB->getTerminator()->getPrevNode());
>> > + }
>> > + if (Insts.empty())
>> > + Fail = true;
>> > + }
>> > +
>> > + bool isValid() const { return !Fail; }
>> > + ArrayRef<Instruction *> operator*() const { return Insts; }
>> > + SmallPtrSet<BasicBlock *, 4> &getActiveBlocks() { return
>> ActiveBlocks; }
>> > +
>> > + void restrictToBlocks(SmallPtrSetImpl<BasicBlock *> &Blocks) {
>> > + for (auto II = Insts.begin(); II != Insts.end();) {
>> > + if (std::find(Blocks.begin(), Blocks.end(), (*II)->getParent())
>> ==
>> > + Blocks.end()) {
>> > + ActiveBlocks.erase((*II)->getParent());
>> > + II = Insts.erase(II);
>> > + } else {
>> > + ++II;
>> > + }
>> > + }
>> > + }
>> > +
>> > + void operator--() {
>> > + if (Fail)
>> > + return;
>> > + SmallVector<Instruction *, 4> NewInsts;
>> > + for (auto *Inst : Insts) {
>> > + if (Inst == &Inst->getParent()->front())
>> > + ActiveBlocks.erase(Inst->getParent());
>> > + else
>> > + NewInsts.push_back(Inst->getPrevNode());
>> > + }
>> > + if (NewInsts.empty()) {
>> > + Fail = true;
>> > + return;
>> > + }
>> > + Insts = NewInsts;
>> > + }
>> > +};
>> > +
>> >
>> +//===----------------------------------------------------------------------===//
>> > +
>> > +/// Candidate solution for sinking. There may be different ways to
>> > +/// sink instructions, differing in the number of instructions sunk,
>> > +/// the number of predecessors sunk from and the number of PHIs
>> > +/// required.
>> > +struct SinkingInstructionCandidate {
>> > + unsigned NumBlocks;
>> > + unsigned NumInstructions;
>> > + unsigned NumPHIs;
>> > + unsigned NumMemoryInsts;
>> > + int Cost = -1;
>> > + SmallVector<BasicBlock *, 4> Blocks;
>> > +
>> > + void calculateCost(unsigned NumOrigPHIs, unsigned NumOrigBlocks) {
>> > + unsigned NumExtraPHIs = NumPHIs - NumOrigPHIs;
>> > + unsigned SplitEdgeCost = (NumOrigBlocks > NumBlocks) ? 2 : 0;
>> > + Cost = (NumInstructions * (NumBlocks - 1)) -
>> > + (NumExtraPHIs *
>> > + NumExtraPHIs) // PHIs are expensive, so make sure they're
>> worth it.
>> > + - SplitEdgeCost;
>> > + }
>> > + bool operator>=(const SinkingInstructionCandidate &Other) const {
>> > + return Cost >= Other.Cost;
>> > + }
>> > +};
>> > +
>> > +llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
>> > + const SinkingInstructionCandidate &C) {
>> > + OS << "<Candidate Cost=" << C.Cost << " #Blocks=" << C.NumBlocks
>> > + << " #Insts=" << C.NumInstructions << " #PHIs=" << C.NumPHIs <<
>> ">";
>> > + return OS;
>> > +}
>> > +
>> >
>> +//===----------------------------------------------------------------------===//
>> > +
>> > +/// Describes a PHI node that may or may not exist. These track the
>> PHIs
>> > +/// that must be created if we sunk a sequence of instructions. It
>> provides
>> > +/// a hash function for efficient equality comparisons.
>> > +class ModelledPHI {
>> > + SmallVector<Value *, 4> Values;
>> > + SmallVector<BasicBlock *, 4> Blocks;
>> > +
>> > +public:
>> > + ModelledPHI() {}
>> > + ModelledPHI(const PHINode *PN) {
>> > + for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I)
>> > + Blocks.push_back(PN->getIncomingBlock(I));
>> > + std::sort(Blocks.begin(), Blocks.end());
>> > +
>> > + // This assumes the PHI is already well-formed and there aren't
>> conflicting
>> > + // incoming values for the same block.
>> > + for (auto *B : Blocks)
>> > + Values.push_back(PN->getIncomingValueForBlock(B));
>> > + }
>> > + /// Create a dummy ModelledPHI that will compare unequal to any
>> other ModelledPHI
>> > + /// without the same ID.
>> > + /// \note This is specifically for DenseMapInfo - do not use this!
>> > + static ModelledPHI createDummy(unsigned ID) {
>> > + ModelledPHI M;
>> > + M.Values.push_back(reinterpret_cast<Value*>(ID));
>> > + return M;
>> > + }
>> > +
>> > + /// Create a PHI from an array of incoming values and incoming
>> blocks.
>> > + template <typename VArray, typename BArray>
>> > + ModelledPHI(const VArray &V, const BArray &B) {
>> > + std::copy(V.begin(), V.end(), std::back_inserter(Values));
>> > + std::copy(B.begin(), B.end(), std::back_inserter(Blocks));
>> > + }
>> > +
>> > + /// Create a PHI from [I[OpNum] for I in Insts].
>> > + template <typename BArray>
>> > + ModelledPHI(ArrayRef<Instruction *> Insts, unsigned OpNum, const
>> BArray &B) {
>> > + std::copy(B.begin(), B.end(), std::back_inserter(Blocks));
>> > + for (auto *I : Insts)
>> > + Values.push_back(I->getOperand(OpNum));
>> > + }
>> > +
>> > + /// Restrict the PHI's contents down to only \c NewBlocks.
>> > + /// \c NewBlocks must be a subset of \c this->Blocks.
>> > + void restrictToBlocks(const SmallPtrSetImpl<BasicBlock *>
>> &NewBlocks) {
>> > + auto BI = Blocks.begin();
>> > + auto VI = Values.begin();
>> > + while (BI != Blocks.end()) {
>> > + assert(VI != Values.end());
>> > + if (std::find(NewBlocks.begin(), NewBlocks.end(), *BI) ==
>> > + NewBlocks.end()) {
>> > + BI = Blocks.erase(BI);
>> > + VI = Values.erase(VI);
>> > + } else {
>> > + ++BI;
>> > + ++VI;
>> > + }
>> > + }
>> > + assert(Blocks.size() == NewBlocks.size());
>> > + }
>> > +
>> > + ArrayRef<Value *> getValues() const { return Values; }
>> > +
>> > + bool areAllIncomingValuesSame() const {
>> > + return all_of(Values, [&](Value *V) { return V == Values[0]; });
>> > + }
>> > + bool areAllIncomingValuesSameType() const {
>> > + return all_of(
>> > + Values, [&](Value *V) { return V->getType() ==
>> Values[0]->getType(); });
>> > + }
>> > + bool areAnyIncomingValuesConstant() const {
>> > + return any_of(Values, [&](Value *V) { return isa<Constant>(V); });
>> > + }
>> > + // Hash functor
>> > + unsigned hash() const {
>> > + return (unsigned)hash_combine_range(Values.begin(),
>> Values.end());
>> > + }
>> > + bool operator==(const ModelledPHI &Other) const {
>> > + return Values == Other.Values && Blocks == Other.Blocks;
>> > + }
>> > +};
>> > +
>> > +template <typename ModelledPHI> struct DenseMapInfo {
>> > + static inline ModelledPHI &getEmptyKey() {
>> > + static ModelledPHI Dummy = ModelledPHI::createDummy(0);
>> > + return Dummy;
>> > + }
>> > + static inline ModelledPHI &getTombstoneKey() {
>> > + static ModelledPHI Dummy = ModelledPHI::createDummy(1);
>> > + return Dummy;
>> > + }
>> > + static unsigned getHashValue(const ModelledPHI &V) { return
>> V.hash(); }
>> > + static bool isEqual(const ModelledPHI &LHS, const ModelledPHI &RHS) {
>> > + return LHS == RHS;
>> > + }
>> > +};
>> > +
>> > +typedef DenseSet<ModelledPHI, DenseMapInfo<ModelledPHI>>
>> ModelledPHISet;
>> > +
>> >
>> +//===----------------------------------------------------------------------===//
>> > +// ValueTable
>> >
>> +//===----------------------------------------------------------------------===//
>> > +// This is a value number table where the value number is a function
>> of the
>> > +// *uses* of a value, rather than its operands. Thus, if VN(A) ==
>> VN(B) we know
>> > +// that the program would be equivalent if we replaced A with PHI(A,
>> B).
>> >
>> +//===----------------------------------------------------------------------===//
>> > +
>> > +/// A GVN expression describing how an instruction is used. The
>> operands
>> > +/// field of BasicExpression is used to store uses, not operands.
>> > +///
>> > +/// This class also contains fields for discriminators used when
>> determining
>> > +/// equivalence of instructions with sideeffects.
>> > +class InstructionUseExpr : public GVNExpression::BasicExpression {
>> > + unsigned MemoryUseOrder = -1;
>> > + bool Volatile = false;
>> > +
>> > +public:
>> > + InstructionUseExpr(Instruction *I, ArrayRecycler<Value *> &R,
>> > + BumpPtrAllocator &A)
>> > + : GVNExpression::BasicExpression(I->getNumUses()) {
>> > + allocateOperands(R, A);
>> > + setOpcode(I->getOpcode());
>> > + setType(I->getType());
>> > +
>> > + for (auto &U : I->uses())
>> > + op_push_back(U.getUser());
>> > + std::sort(op_begin(), op_end());
>> > + }
>> > + void setMemoryUseOrder(unsigned MUO) { MemoryUseOrder = MUO; }
>> > + void setVolatile(bool V) { Volatile = V; }
>> > +
>> > + virtual hash_code getHashValue() const {
>> > + return hash_combine(GVNExpression::BasicExpression::getHashValue(),
>> > + MemoryUseOrder, Volatile);
>> > + }
>> > +
>> > + template <typename Function> hash_code getHashValue(Function MapFn) {
>> > + hash_code H =
>> > + hash_combine(getOpcode(), getType(), MemoryUseOrder, Volatile);
>> > + for (auto *V : operands())
>> > + H = hash_combine(H, MapFn(V));
>> > + return H;
>> > + }
>> > +};
>> > +
>> > +class ValueTable {
>> > + DenseMap<Value *, uint32_t> ValueNumbering;
>> > + DenseMap<GVNExpression::Expression *, uint32_t> ExpressionNumbering;
>> > + DenseMap<size_t, uint32_t> HashNumbering;
>> > + BumpPtrAllocator Allocator;
>> > + ArrayRecycler<Value *> Recycler;
>> > + uint32_t nextValueNumber;
>> > +
>> > + /// Create an expression for I based on its opcode and its uses. If I
>> > + /// touches or reads memory, the expression is also based upon its
>> memory
>> > + /// order - see \c getMemoryUseOrder().
>> > + InstructionUseExpr *createExpr(Instruction *I) {
>> > + InstructionUseExpr *E =
>> > + new (Allocator) InstructionUseExpr(I, Recycler, Allocator);
>> > + if (isMemoryInst(I))
>> > + E->setMemoryUseOrder(getMemoryUseOrder(I));
>> > +
>> > + if (CmpInst *C = dyn_cast<CmpInst>(I)) {
>> > + CmpInst::Predicate Predicate = C->getPredicate();
>> > + E->setOpcode((C->getOpcode() << 8) | Predicate);
>> > + }
>> > + return E;
>> > + }
>> > +
>> > + /// Helper to compute the value number for a memory instruction
>> > + /// (LoadInst/StoreInst), including checking the memory ordering and
>> > + /// volatility.
>> > + template <class Inst> InstructionUseExpr *createMemoryExpr(Inst *I) {
>> > + if (isStrongerThanUnordered(I->getOrdering()) || I->isAtomic())
>> > + return nullptr;
>> > + InstructionUseExpr *E = createExpr(I);
>> > + E->setVolatile(I->isVolatile());
>> > + return E;
>> > + }
>> > +
>> > +public:
>> > + /// Returns the value number for the specified value, assigning
>> > + /// it a new number if it did not have one before.
>> > + uint32_t lookupOrAdd(Value *V) {
>> > + auto VI = ValueNumbering.find(V);
>> > + if (VI != ValueNumbering.end())
>> > + return VI->second;
>> > +
>> > + if (!isa<Instruction>(V)) {
>> > + ValueNumbering[V] = nextValueNumber;
>> > + return nextValueNumber++;
>> > + }
>> > +
>> > + Instruction *I = cast<Instruction>(V);
>> > + InstructionUseExpr *exp = nullptr;
>> > + switch (I->getOpcode()) {
>> > + case Instruction::Load:
>> > + exp = createMemoryExpr(cast<LoadInst>(I));
>> > + break;
>> > + case Instruction::Store:
>> > + exp = createMemoryExpr(cast<StoreInst>(I));
>> > + break;
>> > + case Instruction::Call:
>> > + case Instruction::Invoke:
>> > + case Instruction::Add:
>> > + case Instruction::FAdd:
>> > + case Instruction::Sub:
>> > + case Instruction::FSub:
>> > + case Instruction::Mul:
>> > + case Instruction::FMul:
>> > + case Instruction::UDiv:
>> > + case Instruction::SDiv:
>> > + case Instruction::FDiv:
>> > + case Instruction::URem:
>> > + case Instruction::SRem:
>> > + case Instruction::FRem:
>> > + case Instruction::Shl:
>> > + case Instruction::LShr:
>> > + case Instruction::AShr:
>> > + case Instruction::And:
>> > + case Instruction::Or:
>> > + case Instruction::Xor:
>> > + case Instruction::ICmp:
>> > + case Instruction::FCmp:
>> > + case Instruction::Trunc:
>> > + case Instruction::ZExt:
>> > + case Instruction::SExt:
>> > + case Instruction::FPToUI:
>> > + case Instruction::FPToSI:
>> > + case Instruction::UIToFP:
>> > + case Instruction::SIToFP:
>> > + case Instruction::FPTrunc:
>> > + case Instruction::FPExt:
>> > + case Instruction::PtrToInt:
>> > + case Instruction::IntToPtr:
>> > + case Instruction::BitCast:
>> > + case Instruction::Select:
>> > + case Instruction::ExtractElement:
>> > + case Instruction::InsertElement:
>> > + case Instruction::ShuffleVector:
>> > + case Instruction::InsertValue:
>> > + case Instruction::GetElementPtr:
>> > + exp = createExpr(I);
>> > + break;
>> > + default:
>> > + break;
>> > + }
>> > +
>> > + if (!exp) {
>> > + ValueNumbering[V] = nextValueNumber;
>> > + return nextValueNumber++;
>> > + }
>> > +
>> > + uint32_t e = ExpressionNumbering[exp];
>> > + if (!e) {
>> > + hash_code H = exp->getHashValue([=](Value *V) { return
>> lookupOrAdd(V); });
>> > + auto I = HashNumbering.find(H);
>> > + if (I != HashNumbering.end()) {
>> > + e = I->second;
>> > + } else {
>> > + e = nextValueNumber++;
>> > + HashNumbering[H] = e;
>> > + ExpressionNumbering[exp] = e;
>> > + }
>> > + }
>> > + ValueNumbering[V] = e;
>> > + return e;
>> > + }
>> > +
>> > + /// Returns the value number of the specified value. Fails if the
>> value has
>> > + /// not yet been numbered.
>> > + uint32_t lookup(Value *V) const {
>> > + auto VI = ValueNumbering.find(V);
>> > + assert(VI != ValueNumbering.end() && "Value not numbered?");
>> > + return VI->second;
>> > + }
>> > +
>> > + /// Removes all value numberings and resets the value table.
>> > + void clear() {
>> > + ValueNumbering.clear();
>> > + ExpressionNumbering.clear();
>> > + HashNumbering.clear();
>> > + Recycler.clear(Allocator);
>> > + nextValueNumber = 1;
>> > + }
>> > +
>> > + ValueTable() : nextValueNumber(1) {}
>> > +
>> > + /// \c Inst uses or touches memory. Return an ID describing the
>> memory state
>> > + /// at \c Inst such that if getMemoryUseOrder(I1) ==
>> getMemoryUseOrder(I2),
>> > + /// the exact same memory operations happen after I1 and I2.
>> > + ///
>> > + /// This is a very hard problem in general, so we use domain-specific
>> > + /// knowledge that we only ever check for equivalence between blocks
>> sharing a
>> > + /// single immediate successor that is common, and when determining
>> if I1 ==
>> > + /// I2 we will have already determined that next(I1) == next(I2).
>> This
>> > + /// inductive property allows us to simply return the value number
>> of the next
>> > + /// instruction that defines memory.
>> > + uint32_t getMemoryUseOrder(Instruction *Inst) {
>> > + auto *BB = Inst->getParent();
>> > + for (auto I = std::next(Inst->getIterator()), E = BB->end();
>> > + I != E && !I->isTerminator(); ++I) {
>> > + if (!isMemoryInst(&*I))
>> > + continue;
>> > + if (isa<LoadInst>(&*I))
>> > + continue;
>> > + CallInst *CI = dyn_cast<CallInst>(&*I);
>> > + if (CI && CI->onlyReadsMemory())
>> > + continue;
>> > + InvokeInst *II = dyn_cast<InvokeInst>(&*I);
>> > + if (II && II->onlyReadsMemory())
>> > + continue;
>> > + return lookupOrAdd(&*I);
>> > + }
>> > + return 0;
>> > + }
>> > +};
>> > +
>> >
>> +//===----------------------------------------------------------------------===//
>> > +
>> > +class GVNSink {
>> > +public:
>> > + GVNSink() : VN() {}
>> > + bool run(Function &F) {
>> > + DEBUG(dbgs() << "GVNSink: running on function @" << F.getName() <<
>> "\n");
>> > +
>> > + unsigned NumSunk = 0;
>> > + ReversePostOrderTraversal<Function*> RPOT(&F);
>> > + for (auto *N : RPOT)
>> > + NumSunk += sinkBB(N);
>> > +
>> > + return NumSunk > 0;
>> > + }
>> > +
>> > +private:
>> > + ValueTable VN;
>> > +
>> > + bool isInstructionBlacklisted(Instruction *I) {
>> > + // These instructions may change or break semantics if moved.
>> > + if (isa<PHINode>(I) || I->isEHPad() || isa<AllocaInst>(I) ||
>> > + I->getType()->isTokenTy())
>> > + return true;
>> > + return false;
>> > + }
>> > +
>> > + /// The main heuristic function. Analyze the set of instructions
>> pointed to by
>> > + /// LRI and return a candidate solution if these instructions can be
>> sunk, or
>> > + /// None otherwise.
>> > + Optional<SinkingInstructionCandidate> analyzeInstructionForSinking(
>> > + LockstepReverseIterator &LRI, unsigned &InstNum, unsigned
>> &MemoryInstNum,
>> > + ModelledPHISet &NeededPHIs, SmallPtrSetImpl<Value *>
>> &PHIContents);
>> > +
>> > + /// Create a ModelledPHI for each PHI in BB, adding to PHIs.
>> > + void analyzeInitialPHIs(BasicBlock *BB, ModelledPHISet &PHIs,
>> > + SmallPtrSetImpl<Value *> &PHIContents) {
>> > + for (auto &I : *BB) {
>> > + auto *PN = dyn_cast<PHINode>(&I);
>> > + if (!PN)
>> > + return;
>> > +
>> > + auto MPHI = ModelledPHI(PN);
>> > + PHIs.insert(MPHI);
>> > + for (auto *V : MPHI.getValues())
>> > + PHIContents.insert(V);
>> > + }
>> > + }
>> > +
>> > + /// The main instruction sinking driver. Set up state and try and
>> sink
>> > + /// instructions into BBEnd from its predecessors.
>> > + unsigned sinkBB(BasicBlock *BBEnd);
>> > +
>> > + /// Perform the actual mechanics of sinking an instruction from
>> Blocks into
>> > + /// BBEnd, which is their only successor.
>> > + void sinkLastInstruction(ArrayRef<BasicBlock *> Blocks, BasicBlock
>> *BBEnd);
>> > +
>> > + /// Remove PHIs that all have the same incoming value.
>> > + void foldPointlessPHINodes(BasicBlock *BB) {
>> > + auto I = BB->begin();
>> > + while (PHINode *PN = dyn_cast<PHINode>(I++)) {
>> > + if (!all_of(PN->incoming_values(),
>> > + [&](const Value *V) { return V ==
>> PN->getIncomingValue(0); }))
>> > + continue;
>> > + if (PN->getIncomingValue(0) != PN)
>> > + PN->replaceAllUsesWith(PN->getIncomingValue(0));
>> > + else
>> > + PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
>> > + PN->eraseFromParent();
>> > + }
>> > + }
>> > +};
>> > +
>> > +Optional<SinkingInstructionCandidate>
>> GVNSink::analyzeInstructionForSinking(
>> > + LockstepReverseIterator &LRI, unsigned &InstNum, unsigned
>> &MemoryInstNum,
>> > + ModelledPHISet &NeededPHIs, SmallPtrSetImpl<Value *> &PHIContents) {
>> > + auto Insts = *LRI;
>> > + DEBUG(dbgs() << " -- Analyzing instruction set: [\n"; for (auto *I
>> > + : Insts) {
>> > + I->dump();
>> > + } dbgs() << " ]\n";);
>> > +
>> > + DenseMap<uint32_t, unsigned> VNums;
>> > + for (auto *I : Insts) {
>> > + uint32_t N = VN.lookupOrAdd(I);
>> > + DEBUG(dbgs() << " VN=" << utohexstr(N) << " for" << *I << "\n");
>> > + if (N == ~0U)
>> > + return None;
>> > + VNums[N]++;
>> > + }
>> > + unsigned VNumToSink =
>> > + std::max_element(VNums.begin(), VNums.end(),
>> > + [](const std::pair<uint32_t, unsigned> &I,
>> > + const std::pair<uint32_t, unsigned> &J) {
>> > + return I.second < J.second;
>> > + })
>> > + ->first;
>> > +
>> > + if (VNums[VNumToSink] == 1)
>> > + // Can't sink anything!
>> > + return None;
>> > +
>> > + // Now restrict the number of incoming blocks down to only those with
>> > + // VNumToSink.
>> > + auto &ActivePreds = LRI.getActiveBlocks();
>> > + unsigned InitialActivePredSize = ActivePreds.size();
>> > + SmallVector<Instruction *, 4> NewInsts;
>> > + for (auto *I : Insts) {
>> > + if (VN.lookup(I) != VNumToSink)
>> > + ActivePreds.erase(I->getParent());
>> > + else
>> > + NewInsts.push_back(I);
>> > + }
>> > + for (auto *I : NewInsts)
>> > + if (isInstructionBlacklisted(I))
>> > + return None;
>> > +
>> > + // If we've restricted the incoming blocks, restrict all needed PHIs
>> also
>> > + // to that set.
>> > + bool RecomputePHIContents = false;
>> > + if (ActivePreds.size() != InitialActivePredSize) {
>> > + ModelledPHISet NewNeededPHIs;
>> > + for (auto P : NeededPHIs) {
>> > + P.restrictToBlocks(ActivePreds);
>> > + NewNeededPHIs.insert(P);
>> > + }
>> > + NeededPHIs = NewNeededPHIs;
>> > + LRI.restrictToBlocks(ActivePreds);
>> > + RecomputePHIContents = true;
>> > + }
>> > +
>> > + // The sunk instruction's results.
>> > + ModelledPHI NewPHI(NewInsts, ActivePreds);
>> > +
>> > + // Does sinking this instruction render previous PHIs redundant?
>> > + if (NeededPHIs.find(NewPHI) != NeededPHIs.end()) {
>> > + NeededPHIs.erase(NewPHI);
>> > + RecomputePHIContents = true;
>> > + }
>> > +
>> > + if (RecomputePHIContents) {
>> > + // The needed PHIs have changed, so recompute the set of all needed
>> > + // values.
>> > + PHIContents.clear();
>> > + for (auto &PHI : NeededPHIs)
>> > + PHIContents.insert(PHI.getValues().begin(),
>> PHI.getValues().end());
>> > + }
>> > +
>> > + // Is this instruction required by a later PHI that doesn't match
>> this PHI?
>> > + // if so, we can't sink this instruction.
>> > + for (auto *V : NewPHI.getValues())
>> > + if (PHIContents.count(V))
>> > + // V exists in this PHI, but the whole PHI is different to NewPHI
>> > + // (else it would have been removed earlier). We cannot continue
>> > + // because this isn't representable.
>> > + return None;
>> > +
>> > + // Which operands need PHIs?
>> > + // FIXME: If any of these fail, we should partition up the
>> candidates to
>> > + // try and continue making progress.
>> > + Instruction *I0 = NewInsts[0];
>> > + for (unsigned OpNum = 0, E = I0->getNumOperands(); OpNum != E;
>> ++OpNum) {
>> > + ModelledPHI PHI(NewInsts, OpNum, ActivePreds);
>> > + if (PHI.areAllIncomingValuesSame())
>> > + continue;
>> > + if (!canReplaceOperandWithVariable(I0, OpNum))
>> > + // We can 't create a PHI from this instruction!
>> > + return None;
>> > + if (NeededPHIs.count(PHI))
>> > + continue;
>> > + if (!PHI.areAllIncomingValuesSameType())
>> > + return None;
>> > + // Don't create indirect calls! The called value is the final
>> operand.
>> > + if ((isa<CallInst>(I0) || isa<InvokeInst>(I0)) && OpNum == E - 1 &&
>> > + PHI.areAnyIncomingValuesConstant())
>> > + return None;
>> > +
>> > + NeededPHIs.reserve(NeededPHIs.size());
>> > + NeededPHIs.insert(PHI);
>> > + PHIContents.insert(PHI.getValues().begin(), PHI.getValues().end());
>> > + }
>> > +
>> > + if (isMemoryInst(NewInsts[0]))
>> > + ++MemoryInstNum;
>> > +
>> > + SinkingInstructionCandidate Cand;
>> > + Cand.NumInstructions = ++InstNum;
>> > + Cand.NumMemoryInsts = MemoryInstNum;
>> > + Cand.NumBlocks = ActivePreds.size();
>> > + Cand.NumPHIs = NeededPHIs.size();
>> > + for (auto *C : ActivePreds)
>> > + Cand.Blocks.push_back(C);
>> > +
>> > + return Cand;
>> > +}
>> > +
>> > +unsigned GVNSink::sinkBB(BasicBlock *BBEnd) {
>> > + DEBUG(dbgs() << "GVNSink: running on basic block ";
>> > + BBEnd->printAsOperand(dbgs()); dbgs() << "\n");
>> > + SmallVector<BasicBlock *, 4> Preds;
>> > + for (auto *B : predecessors(BBEnd)) {
>> > + auto *T = B->getTerminator();
>> > + if (isa<BranchInst>(T) || isa<SwitchInst>(T))
>> > + Preds.push_back(B);
>> > + else
>> > + return 0;
>> > + }
>> > + if (Preds.size() < 2)
>> > + return 0;
>> > + std::sort(Preds.begin(), Preds.end());
>> > +
>> > + unsigned NumOrigPreds = Preds.size();
>> > + // We can only sink instructions through unconditional branches.
>> > + for (auto I = Preds.begin(); I != Preds.end();) {
>> > + if ((*I)->getTerminator()->getNumSuccessors() != 1)
>> > + I = Preds.erase(I);
>> > + else
>> > + ++I;
>> > + }
>> > +
>> > + LockstepReverseIterator LRI(Preds);
>> > + SmallVector<SinkingInstructionCandidate, 4> Candidates;
>> > + unsigned InstNum = 0, MemoryInstNum = 0;
>> > + ModelledPHISet NeededPHIs;
>> > + SmallPtrSet<Value *, 4> PHIContents;
>> > + analyzeInitialPHIs(BBEnd, NeededPHIs, PHIContents);
>> > + unsigned NumOrigPHIs = NeededPHIs.size();
>> > +
>> > + while (LRI.isValid()) {
>> > + auto Cand = analyzeInstructionForSinking(LRI, InstNum,
>> MemoryInstNum,
>> > + NeededPHIs, PHIContents);
>> > + if (!Cand)
>> > + break;
>> > + Cand->calculateCost(NumOrigPHIs, Preds.size());
>> > + Candidates.emplace_back(*Cand);
>> > + --LRI;
>> > + }
>> > +
>> > + std::stable_sort(
>> > + Candidates.begin(), Candidates.end(),
>> > + [](const SinkingInstructionCandidate &A,
>> > + const SinkingInstructionCandidate &B) { return A >= B; });
>>
>> std::stable_sort requires a strict weak ordering, so the predicate
>> should never return true if A and B are equal. This code violates
>> that.
>>
>> > + DEBUG(dbgs() << " -- Sinking candidates:\n"; for (auto &C
>> > + : Candidates)
>> dbgs()
>> > + << " " << C << "\n";);
>> > +
>> > + // Pick the top candidate, as long it is positive!
>> > + if (Candidates.empty() || Candidates.front().Cost <= 0)
>> > + return 0;
>> > + auto C = Candidates.front();
>> > +
>> > + DEBUG(dbgs() << " -- Sinking: " << C << "\n");
>> > + BasicBlock *InsertBB = BBEnd;
>> > + if (C.Blocks.size() < NumOrigPreds) {
>> > + DEBUG(dbgs() << " -- Splitting edge to ";
>> BBEnd->printAsOperand(dbgs());
>> > + dbgs() << "\n");
>> > + InsertBB = SplitBlockPredecessors(BBEnd, C.Blocks,
>> ".gvnsink.split");
>> > + if (!InsertBB) {
>> > + DEBUG(dbgs() << " -- FAILED to split edge!\n");
>> > + // Edge couldn't be split.
>> > + return 0;
>> > + }
>> > + }
>> > +
>> > + for (unsigned I = 0; I < C.NumInstructions; ++I)
>> > + sinkLastInstruction(C.Blocks, InsertBB);
>> > +
>> > + return C.NumInstructions;
>> > +}
>> > +
>> > +void GVNSink::sinkLastInstruction(ArrayRef<BasicBlock *> Blocks,
>> > + BasicBlock *BBEnd) {
>> > + SmallVector<Instruction *, 4> Insts;
>> > + for (BasicBlock *BB : Blocks)
>> > + Insts.push_back(BB->getTerminator()->getPrevNode());
>> > + Instruction *I0 = Insts.front();
>> > +
>> > + SmallVector<Value *, 4> NewOperands;
>> > + for (unsigned O = 0, E = I0->getNumOperands(); O != E; ++O) {
>> > + bool NeedPHI = any_of(Insts, [&I0, O](const Instruction *I) {
>> > + return I->getOperand(O) != I0->getOperand(O);
>> > + });
>> > + if (!NeedPHI) {
>> > + NewOperands.push_back(I0->getOperand(O));
>> > + continue;
>> > + }
>> > +
>> > + // Create a new PHI in the successor block and populate it.
>> > + auto *Op = I0->getOperand(O);
>> > + assert(!Op->getType()->isTokenTy() && "Can't PHI tokens!");
>> > + auto *PN = PHINode::Create(Op->getType(), Insts.size(),
>> > + Op->getName() + ".sink",
>> &BBEnd->front());
>> > + for (auto *I : Insts)
>> > + PN->addIncoming(I->getOperand(O), I->getParent());
>> > + NewOperands.push_back(PN);
>> > + }
>> > +
>> > + // Arbitrarily use I0 as the new "common" instruction; remap its
>> operands
>> > + // and move it to the start of the successor block.
>> > + for (unsigned O = 0, E = I0->getNumOperands(); O != E; ++O)
>> > + I0->getOperandUse(O).set(NewOperands[O]);
>> > + I0->moveBefore(&*BBEnd->getFirstInsertionPt());
>> > +
>> > + // Update metadata and IR flags.
>> > + for (auto *I : Insts)
>> > + if (I != I0) {
>> > + combineMetadataForCSE(I0, I);
>> > + I0->andIRFlags(I);
>> > + }
>> > +
>> > + for (auto *I : Insts)
>> > + if (I != I0)
>> > + I->replaceAllUsesWith(I0);
>> > + foldPointlessPHINodes(BBEnd);
>> > +
>> > + // Finally nuke all instructions apart from the common instruction.
>> > + for (auto *I : Insts)
>> > + if (I != I0)
>> > + I->eraseFromParent();
>> > +
>> > + NumRemoved += Insts.size() - 1;
>> > +}
>> > +
>> >
>> +////////////////////////////////////////////////////////////////////////////////
>> > +// Pass machinery / boilerplate
>> > +
>> > +class GVNSinkLegacyPass : public FunctionPass {
>> > +public:
>> > + static char ID;
>> > +
>> > + GVNSinkLegacyPass() : FunctionPass(ID) {
>> > + initializeGVNSinkLegacyPassPass(*PassRegistry::getPassRegistry());
>> > + }
>> > +
>> > + bool runOnFunction(Function &F) override {
>> > + if (skipFunction(F))
>> > + return false;
>> > + GVNSink G;
>> > + return G.run(F);
>> > + }
>> > +
>> > + void getAnalysisUsage(AnalysisUsage &AU) const override {
>> > + AU.addPreserved<GlobalsAAWrapperPass>();
>> > + }
>> > +};
>> > +} // namespace
>> > +
>> > +PreservedAnalyses GVNSinkPass::run(Function &F,
>> FunctionAnalysisManager &AM) {
>> > + GVNSink G;
>> > + if (!G.run(F))
>> > + return PreservedAnalyses::all();
>> > +
>> > + PreservedAnalyses PA;
>> > + PA.preserve<GlobalsAA>();
>> > + return PA;
>> > +}
>> > +
>> > +char GVNSinkLegacyPass::ID = 0;
>> > +INITIALIZE_PASS_BEGIN(GVNSinkLegacyPass, "gvn-sink",
>> > + "Early GVN sinking of Expressions", false, false)
>> > +INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
>> > +INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
>> > +INITIALIZE_PASS_END(GVNSinkLegacyPass, "gvn-sink",
>> > + "Early GVN sinking of Expressions", false, false)
>> > +
>> > +FunctionPass *llvm::createGVNSinkPass() { return new
>> GVNSinkLegacyPass(); }
>> >
>> > Modified: llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Scalar.cpp?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Scalar/Scalar.cpp (original)
>> > +++ llvm/trunk/lib/Transforms/Scalar/Scalar.cpp Thu May 25 07:51:11 2017
>> > @@ -48,6 +48,7 @@ void llvm::initializeScalarOpts(PassRegi
>> > initializeEarlyCSELegacyPassPass(Registry);
>> > initializeEarlyCSEMemSSALegacyPassPass(Registry);
>> > initializeGVNHoistLegacyPassPass(Registry);
>> > + initializeGVNSinkLegacyPassPass(Registry);
>> > initializeFlattenCFGPassPass(Registry);
>> > initializeInductiveRangeCheckEliminationPass(Registry);
>> > initializeIndVarSimplifyLegacyPassPass(Registry);
>> >
>> > Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
>> > +++ llvm/trunk/lib/Transforms/Utils/Local.cpp Thu May 25 07:51:11 2017
>> > @@ -2109,3 +2109,48 @@ void llvm::maybeMarkSanitizerLibraryCall
>> > !F->doesNotAccessMemory())
>> > CI->addAttribute(AttributeList::FunctionIndex,
>> Attribute::NoBuiltin);
>> > }
>> > +
>> > +bool llvm::canReplaceOperandWithVariable(const Instruction *I,
>> unsigned OpIdx) {
>> > + // We can't have a PHI with a metadata type.
>> > + if (I->getOperand(OpIdx)->getType()->isMetadataTy())
>> > + return false;
>> > +
>> > + // Early exit.
>> > + if (!isa<Constant>(I->getOperand(OpIdx)))
>> > + return true;
>> > +
>> > + switch (I->getOpcode()) {
>> > + default:
>> > + return true;
>> > + case Instruction::Call:
>> > + case Instruction::Invoke:
>> > + // Many arithmetic intrinsics have no issue taking a
>> > + // variable, however it's hard to distingish these from
>> > + // specials such as @llvm.frameaddress that require a constant.
>> > + if (isa<IntrinsicInst>(I))
>> > + return false;
>> > +
>> > + // Constant bundle operands may need to retain their constant-ness
>> for
>> > + // correctness.
>> > + if (ImmutableCallSite(I).isBundleOperand(OpIdx))
>> > + return false;
>> > + return true;
>> > + case Instruction::ShuffleVector:
>> > + // Shufflevector masks are constant.
>> > + return OpIdx != 2;
>> > + case Instruction::ExtractValue:
>> > + case Instruction::InsertValue:
>> > + // All operands apart from the first are constant.
>> > + return OpIdx == 0;
>> > + case Instruction::Alloca:
>> > + return false;
>> > + case Instruction::GetElementPtr:
>> > + if (OpIdx == 0)
>> > + return true;
>> > + gep_type_iterator It = gep_type_begin(I);
>> > + for (auto E = std::next(It, OpIdx); It != E; ++It)
>> > + if (It.isStruct())
>> > + return false;
>> > + return true;
>> > + }
>> > +}
>> >
>> > Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=303850&r1=303849&r2=303850&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
>> > +++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Thu May 25 07:51:11
>> 2017
>> > @@ -1376,53 +1376,6 @@ HoistTerminator:
>> > return true;
>> > }
>> >
>> > -// Is it legal to place a variable in operand \c OpIdx of \c I?
>> > -// FIXME: This should be promoted to Instruction.
>> > -static bool canReplaceOperandWithVariable(const Instruction *I,
>> > - unsigned OpIdx) {
>> > - // We can't have a PHI with a metadata type.
>> > - if (I->getOperand(OpIdx)->getType()->isMetadataTy())
>> > - return false;
>> > -
>> > - // Early exit.
>> > - if (!isa<Constant>(I->getOperand(OpIdx)))
>> > - return true;
>> > -
>> > - switch (I->getOpcode()) {
>> > - default:
>> > - return true;
>> > - case Instruction::Call:
>> > - case Instruction::Invoke:
>> > - // FIXME: many arithmetic intrinsics have no issue taking a
>> > - // variable, however it's hard to distingish these from
>> > - // specials such as @llvm.frameaddress that require a constant.
>> > - if (isa<IntrinsicInst>(I))
>> > - return false;
>> > -
>> > - // Constant bundle operands may need to retain their constant-ness
>> for
>> > - // correctness.
>> > - if (ImmutableCallSite(I).isBundleOperand(OpIdx))
>> > - return false;
>> > -
>> > - return true;
>> > -
>> > - case Instruction::ShuffleVector:
>> > - // Shufflevector masks are constant.
>> > - return OpIdx != 2;
>> > - case Instruction::ExtractValue:
>> > - case Instruction::InsertValue:
>> > - // All operands apart from the first are constant.
>> > - return OpIdx == 0;
>> > - case Instruction::Alloca:
>> > - return false;
>> > - case Instruction::GetElementPtr:
>> > - if (OpIdx == 0)
>> > - return true;
>> > - gep_type_iterator It = std::next(gep_type_begin(I), OpIdx - 1);
>> > - return It.isSequential();
>> > - }
>> > -}
>> > -
>> > // All instructions in Insts belong to different blocks that all
>> unconditionally
>> > // branch to a common successor. Analyze each instruction and return
>> true if it
>> > // would be possible to sink them into their successor, creating one
>> common
>> >
>> > Added: llvm/trunk/test/Transforms/GVNSink/dither.ll
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/dither.ll?rev=303850&view=auto
>> >
>> ==============================================================================
>> > --- llvm/trunk/test/Transforms/GVNSink/dither.ll (added)
>> > +++ llvm/trunk/test/Transforms/GVNSink/dither.ll Thu May 25 07:51:11
>> 2017
>> > @@ -0,0 +1,42 @@
>> > +; RUN: opt < %s -S -gvn-sink | FileCheck %s
>> > +
>> > +; Because %tmp17 has flipped operands to its equivalents %tmp14 and
>> %tmp7, we
>> > +; can't sink the zext as we'd need a shuffling PHI in between.
>> > +;
>> > +; Just sinking the zext isn't profitable, so ensure nothing is sunk.
>> > +
>> > +; CHECK-LABEL: @hoge
>> > +; CHECK-NOT: bb18.gvnsink.split
>> > +define void @hoge() {
>> > +bb:
>> > + br i1 undef, label %bb4, label %bb11
>> > +
>> > +bb4: ; preds = %bb3
>> > + br i1 undef, label %bb6, label %bb8
>> > +
>> > +bb6: ; preds = %bb5
>> > + %tmp = zext i16 undef to i64
>> > + %tmp7 = add i64 %tmp, undef
>> > + br label %bb18
>> > +
>> > +bb8: ; preds = %bb5
>> > + %tmp9 = zext i16 undef to i64
>> > + br label %bb18
>> > +
>> > +bb11: ; preds = %bb10
>> > + br i1 undef, label %bb12, label %bb15
>> > +
>> > +bb12: ; preds = %bb11
>> > + %tmp13 = zext i16 undef to i64
>> > + %tmp14 = add i64 %tmp13, undef
>> > + br label %bb18
>> > +
>> > +bb15: ; preds = %bb11
>> > + %tmp16 = zext i16 undef to i64
>> > + %tmp17 = add i64 undef, %tmp16
>> > + br label %bb18
>> > +
>> > +bb18: ; preds = %bb15,
>> %bb12, %bb8, %bb6
>> > + %tmp19 = phi i64 [ %tmp7, %bb6 ], [ undef, %bb8 ], [ %tmp14, %bb12
>> ], [ %tmp17, %bb15 ]
>> > + unreachable
>> > +}
>> >
>> > Added: llvm/trunk/test/Transforms/GVNSink/indirect-call.ll
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/indirect-call.ll?rev=303850&view=auto
>> >
>> ==============================================================================
>> > --- llvm/trunk/test/Transforms/GVNSink/indirect-call.ll (added)
>> > +++ llvm/trunk/test/Transforms/GVNSink/indirect-call.ll Thu May 25
>> 07:51:11 2017
>> > @@ -0,0 +1,70 @@
>> > +; RUN: opt < %s -gvn-sink -simplifycfg -simplifycfg-sink-common=false
>> -S | FileCheck %s
>> > +
>> > +declare i8 @ext(i1)
>> > +
>> > +define zeroext i1 @test1(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32
>> %nblks, i8(i1)* %ext) {
>> > +entry:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +; CHECK-LABEL: test1
>> > +; CHECK: call i8 @ext
>> > +; CHECK: call i8 %ext
>> > +if.then:
>> > + %frombool1 = call i8 @ext(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %frombool3 = call i8 %ext(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +define zeroext i1 @test2(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32
>> %nblks, i8(i1)* %ext) {
>> > +entry:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +; CHECK-LABEL: test2
>> > +; CHECK: call i8 %ext
>> > +; CHECK-NOT: call
>> > +if.then:
>> > + %frombool1 = call i8 %ext(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %frombool3 = call i8 %ext(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +define zeroext i1 @test3(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32
>> %nblks, i8(i1)* %ext1, i8(i1)* %ext2) {
>> > +entry:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +; CHECK-LABEL: test3
>> > +; CHECK: %[[x:.*]] = select i1 %flag, i8 (i1)* %ext1, i8 (i1)* %ext2
>> > +; CHECK: call i8 %[[x]](i1 %cmp)
>> > +; CHECK-NOT: call
>> > +if.then:
>> > + %frombool1 = call i8 %ext1(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %frombool3 = call i8 %ext2(i1 %cmp)
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> >
>> > Added: llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll?rev=303850&view=auto
>> >
>> ==============================================================================
>> > --- llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll (added)
>> > +++ llvm/trunk/test/Transforms/GVNSink/sink-common-code.ll Thu May 25
>> 07:51:11 2017
>> > @@ -0,0 +1,694 @@
>> > +; RUN: opt < %s -gvn-sink -simplifycfg -simplifycfg-sink-common=false
>> -S | FileCheck %s
>> > +
>> > +define zeroext i1 @test1(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32
>> %nblks) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +; CHECK-LABEL: test1
>> > +; CHECK: add
>> > +; CHECK: select
>> > +; CHECK: icmp
>> > +; CHECK-NOT: br
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +define zeroext i1 @test2(i1 zeroext %flag, i32 %blksA, i32 %blksB, i32
>> %nblks) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +; CHECK-LABEL: test2
>> > +; CHECK: add
>> > +; CHECK: select
>> > +; CHECK: icmp
>> > +; CHECK-NOT: br
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp uge i32 %blksA, %add
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +declare i32 @foo(i32, i32) nounwind readnone
>> > +
>> > +define i32 @test3(i1 zeroext %flag, i32 %x, i32 %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %x0 = call i32 @foo(i32 %x, i32 0) nounwind readnone
>> > + %y0 = call i32 @foo(i32 %x, i32 1) nounwind readnone
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %x1 = call i32 @foo(i32 %y, i32 0) nounwind readnone
>> > + %y1 = call i32 @foo(i32 %y, i32 1) nounwind readnone
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %xx = phi i32 [ %x0, %if.then ], [ %x1, %if.else ]
>> > + %yy = phi i32 [ %y0, %if.then ], [ %y1, %if.else ]
>> > + %ret = add i32 %xx, %yy
>> > + ret i32 %ret
>> > +}
>> > +
>> > +; CHECK-LABEL: test3
>> > +; CHECK: select
>> > +; CHECK: call
>> > +; CHECK: call
>> > +; CHECK: add
>> > +; CHECK-NOT: br
>> > +
>> > +define i32 @test4(i1 zeroext %flag, i32 %x, i32* %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %a = add i32 %x, 5
>> > + store i32 %a, i32* %y
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %b = add i32 %x, 7
>> > + store i32 %b, i32* %y
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test4
>> > +; CHECK: select
>> > +; CHECK: store
>> > +; CHECK-NOT: store
>> > +
>> > +define i32 @test5(i1 zeroext %flag, i32 %x, i32* %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %a = add i32 %x, 5
>> > + store volatile i32 %a, i32* %y
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %b = add i32 %x, 7
>> > + store i32 %b, i32* %y
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test5
>> > +; CHECK: store volatile
>> > +; CHECK: store
>> > +
>> > +define i32 @test6(i1 zeroext %flag, i32 %x, i32* %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %a = add i32 %x, 5
>> > + store volatile i32 %a, i32* %y
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %b = add i32 %x, 7
>> > + store volatile i32 %b, i32* %y
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test6
>> > +; CHECK: select
>> > +; CHECK: store volatile
>> > +; CHECK-NOT: store
>> > +
>> > +define i32 @test7(i1 zeroext %flag, i32 %x, i32* %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %z = load volatile i32, i32* %y
>> > + %a = add i32 %z, 5
>> > + store volatile i32 %a, i32* %y
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %w = load volatile i32, i32* %y
>> > + %b = add i32 %w, 7
>> > + store volatile i32 %b, i32* %y
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test7
>> > +; CHECK-DAG: select
>> > +; CHECK-DAG: load volatile
>> > +; CHECK: store volatile
>> > +; CHECK-NOT: load
>> > +; CHECK-NOT: store
>> > +
>> > +; The extra store in %if.then means %z and %w are not equivalent.
>> > +define i32 @test9(i1 zeroext %flag, i32 %x, i32* %y, i32* %p) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + store i32 7, i32* %p
>> > + %z = load volatile i32, i32* %y
>> > + store i32 6, i32* %p
>> > + %a = add i32 %z, 5
>> > + store volatile i32 %a, i32* %y
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %w = load volatile i32, i32* %y
>> > + %b = add i32 %w, 7
>> > + store volatile i32 %b, i32* %y
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test9
>> > +; CHECK: add
>> > +; CHECK: add
>> > +
>> > +%struct.anon = type { i32, i32 }
>> > +
>> > +; The GEP indexes a struct type so cannot have a variable last index.
>> > +define i32 @test10(i1 zeroext %flag, i32 %x, i32* %y, %struct.anon*
>> %s) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %dummy = add i32 %x, 5
>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 0
>> > + store volatile i32 %x, i32* %gepa
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %dummy1 = add i32 %x, 6
>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 1
>> > + store volatile i32 %x, i32* %gepb
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test10
>> > +; CHECK: getelementptr
>> > +; CHECK: store volatile
>> > +; CHECK: getelementptr
>> > +; CHECK: store volatile
>> > +
>> > +; The shufflevector's mask operand cannot be merged in a PHI.
>> > +define i32 @test11(i1 zeroext %flag, i32 %w, <2 x i32> %x, <2 x i32>
>> %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %dummy = add i32 %w, 5
>> > + %sv1 = shufflevector <2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 0,
>> i32 1>
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %dummy1 = add i32 %w, 6
>> > + %sv2 = shufflevector <2 x i32> %x, <2 x i32> %y, <2 x i32> <i32 1,
>> i32 0>
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %p = phi <2 x i32> [ %sv1, %if.then ], [ %sv2, %if.else ]
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test11
>> > +; CHECK: shufflevector
>> > +; CHECK: shufflevector
>> > +
>> > +; We can't common an intrinsic!
>> > +define i32 @test12(i1 zeroext %flag, i32 %w, i32 %x, i32 %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %dummy = add i32 %w, 5
>> > + %sv1 = call i32 @llvm.ctlz.i32(i32 %x)
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %dummy1 = add i32 %w, 6
>> > + %sv2 = call i32 @llvm.cttz.i32(i32 %x)
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %p = phi i32 [ %sv1, %if.then ], [ %sv2, %if.else ]
>> > + ret i32 1
>> > +}
>> > +
>> > +declare i32 @llvm.ctlz.i32(i32 %x) readnone
>> > +declare i32 @llvm.cttz.i32(i32 %x) readnone
>> > +
>> > +; CHECK-LABEL: test12
>> > +; CHECK: call i32 @llvm.ctlz
>> > +; CHECK: call i32 @llvm.cttz
>> > +
>> > +; The TBAA metadata should be properly combined.
>> > +define i32 @test13(i1 zeroext %flag, i32 %x, i32* %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %z = load volatile i32, i32* %y
>> > + %a = add i32 %z, 5
>> > + store volatile i32 %a, i32* %y, !tbaa !3
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %w = load volatile i32, i32* %y
>> > + %b = add i32 %w, 7
>> > + store volatile i32 %b, i32* %y, !tbaa !4
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i32 1
>> > +}
>> > +
>> > +!0 = !{ !"an example type tree" }
>> > +!1 = !{ !"int", !0 }
>> > +!2 = !{ !"float", !0 }
>> > +!3 = !{ !"const float", !2, i64 0 }
>> > +!4 = !{ !"special float", !2, i64 1 }
>> > +
>> > +; CHECK-LABEL: test13
>> > +; CHECK-DAG: select
>> > +; CHECK-DAG: load volatile
>> > +; CHECK: store volatile {{.*}}, !tbaa !0
>> > +; CHECK-NOT: load
>> > +; CHECK-NOT: store
>> > +
>> > +; The call should be commoned.
>> > +define i32 @test13a(i1 zeroext %flag, i32 %w, i32 %x, i32 %y) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %sv1 = call i32 @bar(i32 %x)
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %sv2 = call i32 @bar(i32 %y)
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %p = phi i32 [ %sv1, %if.then ], [ %sv2, %if.else ]
>> > + ret i32 1
>> > +}
>> > +declare i32 @bar(i32)
>> > +
>> > +; CHECK-LABEL: test13a
>> > +; CHECK: %[[x:.*]] = select i1 %flag
>> > +; CHECK: call i32 @bar(i32 %[[x]])
>> > +
>> > +; The load should be commoned.
>> > +define i32 @test14(i1 zeroext %flag, i32 %w, i32 %x, i32 %y,
>> %struct.anon* %s) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %dummy = add i32 %x, 1
>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 1
>> > + %sv1 = load i32, i32* %gepa
>> > + %cmp1 = icmp eq i32 %sv1, 56
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %dummy2 = add i32 %x, 4
>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 1
>> > + %sv2 = load i32, i32* %gepb
>> > + %cmp2 = icmp eq i32 %sv2, 57
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %p = phi i1 [ %cmp1, %if.then ], [ %cmp2, %if.else ]
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test14
>> > +; CHECK: getelementptr
>> > +; CHECK: load
>> > +; CHECK-NOT: load
>> > +
>> > +; The load should be commoned.
>> > +define i32 @test15(i1 zeroext %flag, i32 %w, i32 %x, i32 %y,
>> %struct.anon* %s) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %dummy = add i32 %x, 1
>> > + %gepa = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 0
>> > + %sv1 = load i32, i32* %gepa
>> > + %ext1 = zext i32 %sv1 to i64
>> > + %cmp1 = icmp eq i64 %ext1, 56
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %dummy2 = add i32 %x, 4
>> > + %gepb = getelementptr inbounds %struct.anon, %struct.anon* %s, i32
>> 0, i32 1
>> > + %sv2 = load i32, i32* %gepb
>> > + %ext2 = zext i32 %sv2 to i64
>> > + %cmp2 = icmp eq i64 %ext2, 56
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %p = phi i1 [ %cmp1, %if.then ], [ %cmp2, %if.else ]
>> > + ret i32 1
>> > +}
>> > +
>> > +; CHECK-LABEL: test15
>> > +; CHECK: getelementptr
>> > +; CHECK: load
>> > +; CHECK-NOT: load
>> > +
>> > +define zeroext i1 @test_crash(i1 zeroext %flag, i32* %i4, i32* %m,
>> i32* %n) {
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %tmp1 = load i32, i32* %i4
>> > + %tmp2 = add i32 %tmp1, -1
>> > + store i32 %tmp2, i32* %i4
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + %tmp3 = load i32, i32* %m
>> > + %tmp4 = load i32, i32* %n
>> > + %tmp5 = add i32 %tmp3, %tmp4
>> > + store i32 %tmp5, i32* %i4
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i1 true
>> > +}
>> > +
>> > +; CHECK-LABEL: test_crash
>> > +; No checks for test_crash - just ensure it doesn't crash!
>> > +
>> > +define zeroext i1 @test16(i1 zeroext %flag, i1 zeroext %flag2, i32
>> %blksA, i32 %blksB, i32 %nblks) {
>> > +
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + br i1 %flag2, label %if.then2, label %if.end
>> > +
>> > +if.then2:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.then2
>> ], [ 0, %if.else ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +; CHECK-LABEL: test16
>> > +; CHECK: zext
>> > +; CHECK: zext
>> > +
>> > +define zeroext i1 @test16a(i1 zeroext %flag, i1 zeroext %flag2, i32
>> %blksA, i32 %blksB, i32 %nblks, i8* %p) {
>> > +
>> > +entry:
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + %b1 = sext i8 %frombool1 to i32
>> > + %b2 = trunc i32 %b1 to i8
>> > + store i8 %b2, i8* %p
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + br i1 %flag2, label %if.then2, label %if.end
>> > +
>> > +if.then2:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + %a1 = sext i8 %frombool3 to i32
>> > + %a2 = trunc i32 %a1 to i8
>> > + store i8 %a2, i8* %p
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i1 true
>> > +}
>> > +
>> > +; CHECK-LABEL: test16a
>> > +; CHECK: zext
>> > +; CHECK-NOT: zext
>> > +
>> > +define zeroext i1 @test17(i32 %flag, i32 %blksA, i32 %blksB, i32
>> %nblks) {
>> > +entry:
>> > + switch i32 %flag, label %if.end [
>> > + i32 0, label %if.then
>> > + i32 1, label %if.then2
>> > + ]
>> > +
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = call i8 @i1toi8(i1 %cmp)
>> > + %a1 = sext i8 %frombool1 to i32
>> > + %a2 = trunc i32 %a1 to i8
>> > + br label %if.end
>> > +
>> > +if.then2:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = call i8 @i1toi8(i1 %cmp2)
>> > + %b1 = sext i8 %frombool3 to i32
>> > + %b2 = trunc i32 %b1 to i8
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %a2, %if.then ], [ %b2, %if.then2 ], [ 0, %entry
>> ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +declare i8 @i1toi8(i1)
>> > +
>> > +; FIXME: DISABLED - we don't consider this profitable. We should
>> > +; - Consider argument setup/return mov'ing for calls, like InlineCost
>> does.
>> > +; - Consider the removal of the %obeys.0 PHI (zero PHI movement
>> overall)
>> > +
>> > +; DISABLED-CHECK-LABEL: test17
>> > +; DISABLED-CHECK: if.then:
>> > +; DISABLED-CHECK-NEXT: icmp uge
>> > +; DISABLED-CHECK-NEXT: br label %[[x:.*]]
>> > +
>> > +; DISABLED-CHECK: if.then2:
>> > +; DISABLED-CHECK-NEXT: add
>> > +; DISABLED-CHECK-NEXT: icmp ule
>> > +; DISABLED-CHECK-NEXT: br label %[[x]]
>> > +
>> > +; DISABLED-CHECK: [[x]]:
>> > +; DISABLED-CHECK-NEXT: %[[y:.*]] = phi i1 [ %cmp
>> > +; DISABLED-CHECK-NEXT: %[[z:.*]] = call i8 @i1toi8(i1 %[[y]])
>> > +; DISABLED-CHECK-NEXT: br label %if.end
>> > +
>> > +; DISABLED-CHECK: if.end:
>> > +; DISABLED-CHECK-NEXT: phi i8
>> > +; DISABLED-CHECK-DAG: [ %[[z]], %[[x]] ]
>> > +; DISABLED-CHECK-DAG: [ 0, %entry ]
>> > +
>> > +define zeroext i1 @test18(i32 %flag, i32 %blksA, i32 %blksB, i32
>> %nblks) {
>> > +entry:
>> > + switch i32 %flag, label %if.then3 [
>> > + i32 0, label %if.then
>> > + i32 1, label %if.then2
>> > + ]
>> > +
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + br label %if.end
>> > +
>> > +if.then2:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + br label %if.end
>> > +
>> > +if.then3:
>> > + %add2 = add i32 %nblks, %blksA
>> > + %cmp3 = icmp ule i32 %add2, %blksA
>> > + %frombool4 = zext i1 %cmp3 to i8
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + %obeys.0 = phi i8 [ %frombool1, %if.then ], [ %frombool3, %if.then2
>> ], [ %frombool4, %if.then3 ]
>> > + %tobool4 = icmp ne i8 %obeys.0, 0
>> > + ret i1 %tobool4
>> > +}
>> > +
>> > +; CHECK-LABEL: test18
>> > +; CHECK: if.end:
>> > +; CHECK-NEXT: %[[x:.*]] = phi i1
>> > +; CHECK-DAG: [ %cmp, %if.then ]
>> > +; CHECK-DAG: [ %cmp2, %if.then2 ]
>> > +; CHECK-DAG: [ %cmp3, %if.then3 ]
>> > +; CHECK-NEXT: zext i1 %[[x]] to i8
>> > +
>> > +; The phi is confusing - both add instructions are used by it, but
>> > +; not on their respective unconditional arcs. It should not be
>> > +; optimized.
>> > +define void @test_pr30292(i1 %cond, i1 %cond2, i32 %a, i32 %b) {
>> > +entry:
>> > + %add1 = add i32 %a, 1
>> > + br label %succ
>> > +
>> > +one:
>> > + br i1 %cond, label %two, label %succ
>> > +
>> > +two:
>> > + call void @g()
>> > + %add2 = add i32 %a, 1
>> > + br label %succ
>> > +
>> > +succ:
>> > + %p = phi i32 [ 0, %entry ], [ %add1, %one ], [ %add2, %two ]
>> > + br label %one
>> > +}
>> > +declare void @g()
>> > +
>> > +; CHECK-LABEL: test_pr30292
>> > +; CHECK: phi i32 [ 0, %entry ], [ %add1, %succ ], [ %add2, %two ]
>> > +
>> > +define zeroext i1 @test_pr30244(i1 zeroext %flag, i1 zeroext %flag2,
>> i32 %blksA, i32 %blksB, i32 %nblks) {
>> > +
>> > +entry:
>> > + %p = alloca i8
>> > + br i1 %flag, label %if.then, label %if.else
>> > +
>> > +if.then:
>> > + %cmp = icmp uge i32 %blksA, %nblks
>> > + %frombool1 = zext i1 %cmp to i8
>> > + store i8 %frombool1, i8* %p
>> > + br label %if.end
>> > +
>> > +if.else:
>> > + br i1 %flag2, label %if.then2, label %if.end
>> > +
>> > +if.then2:
>> > + %add = add i32 %nblks, %blksB
>> > + %cmp2 = icmp ule i32 %add, %blksA
>> > + %frombool3 = zext i1 %cmp2 to i8
>> > + store i8 %frombool3, i8* %p
>> > + br label %if.end
>> > +
>> > +if.end:
>> > + ret i1 tr
>
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