[llvm] r303850 - [GVNSink] GVNSink pass
Benjamin Kramer via llvm-commits
llvm-commits at lists.llvm.org
Thu May 25 09:05:24 PDT 2017
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 true
> +}
> +
> +; CHECK-LABEL: @test_pr30244
> +; CHECK: store
> +; CHECK-NOT: store
> +
> +define i32 @test_pr30373a(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
> + %z0 = lshr i32 %y0, 8
> + 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
> + %z1 = lshr exact i32 %y1, 8
> + br label %if.end
> +
> +if.end:
> + %xx = phi i32 [ %x0, %if.then ], [ %x1, %if.else ]
> + %yy = phi i32 [ %z0, %if.then ], [ %z1, %if.else ]
> + %ret = add i32 %xx, %yy
> + ret i32 %ret
> +}
> +
> +; CHECK-LABEL: test_pr30373a
> +; CHECK: lshr
> +; CHECK-NOT: exact
> +; CHECK: }
> +
> +define i32 @test_pr30373b(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
> + %z0 = lshr exact i32 %y0, 8
> + 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
> + %z1 = lshr i32 %y1, 8
> + br label %if.end
> +
> +if.end:
> + %xx = phi i32 [ %x0, %if.then ], [ %x1, %if.else ]
> + %yy = phi i32 [ %z0, %if.then ], [ %z1, %if.else ]
> + %ret = add i32 %xx, %yy
> + ret i32 %ret
> +}
> +
> +; CHECK-LABEL: test_pr30373b
> +; CHECK: lshr
> +; CHECK-NOT: exact
> +; CHECK: }
> +
> +; CHECK: !0 = !{!1, !1, i64 0}
> +; CHECK: !1 = !{!"float", !2}
> +; CHECK: !2 = !{!"an example type tree"}
>
> Added: llvm/trunk/test/Transforms/GVNSink/struct.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVNSink/struct.ll?rev=303850&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/GVNSink/struct.ll (added)
> +++ llvm/trunk/test/Transforms/GVNSink/struct.ll Thu May 25 07:51:11 2017
> @@ -0,0 +1,71 @@
> +; RUN: opt -gvn-sink -S < %s | FileCheck %s
> +
> +%struct = type {i32, i32}
> +%struct2 = type { [ 2 x i32], i32 }
> +
> +; Struct indices cannot be variant.
> +
> +; CHECK-LABEL: @f() {
> +; CHECK: getelementptr
> +; CHECK: getelementptr
> +define void @f() {
> +bb:
> + br i1 undef, label %bb2, label %bb1
> +
> +bb1: ; preds = %bb
> + %tmp = getelementptr inbounds %struct, %struct* null, i64 0, i32 1
> + br label %bb4
> +
> +bb2: ; preds = %bb
> + %tmp3 = getelementptr inbounds %struct, %struct* null, i64 0, i32 0
> + br label %bb4
> +
> +bb4: ; preds = %bb2, %bb1
> + %tmp5 = phi i32 [ 1, %bb1 ], [ 0, %bb2 ]
> + ret void
> +}
> +
> +; Struct indices cannot be variant.
> +
> +; CHECK-LABEL: @g() {
> +; CHECK: getelementptr
> +; CHECK: getelementptr
> +define void @g() {
> +bb:
> + br i1 undef, label %bb2, label %bb1
> +
> +bb1: ; preds = %bb
> + %tmp = getelementptr inbounds %struct2, %struct2* null, i64 0, i32 0, i32 1
> + br label %bb4
> +
> +bb2: ; preds = %bb
> + %tmp3 = getelementptr inbounds %struct2, %struct2* null, i64 0, i32 0, i32 0
> + br label %bb4
> +
> +bb4: ; preds = %bb2, %bb1
> + %tmp5 = phi i32 [ 1, %bb1 ], [ 0, %bb2 ]
> + ret void
> +}
> +
> +
> +; ... but the first parameter to a GEP can.
> +
> +; CHECK-LABEL: @h() {
> +; CHECK: getelementptr
> +; CHECK-NOT: getelementptr
> +define void @h() {
> +bb:
> + br i1 undef, label %bb2, label %bb1
> +
> +bb1: ; preds = %bb
> + %tmp = getelementptr inbounds %struct, %struct* null, i32 0, i32 0
> + br label %bb4
> +
> +bb2: ; preds = %bb
> + %tmp3 = getelementptr inbounds %struct, %struct* null, i32 1, i32 0
> + br label %bb4
> +
> +bb4: ; preds = %bb2, %bb1
> + %tmp5 = phi i32 [ 0, %bb1 ], [ 1, %bb2 ]
> + ret void
> +}
> \ No newline at end of file
>
>
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