summaryrefslogtreecommitdiffstats
path: root/llvm/lib
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib')
-rw-r--r--llvm/lib/Passes/PassRegistry.def1
-rw-r--r--llvm/lib/Transforms/IPO/PassManagerBuilder.cpp1
-rw-r--r--llvm/lib/Transforms/Scalar/CMakeLists.txt1
-rw-r--r--llvm/lib/Transforms/Scalar/GVNHoist.cpp740
-rw-r--r--llvm/lib/Transforms/Scalar/Scalar.cpp5
5 files changed, 0 insertions, 748 deletions
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 0e084396e64..bb430afc96d 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -128,7 +128,6 @@ FUNCTION_PASS("bdce", BDCEPass())
FUNCTION_PASS("dce", DCEPass())
FUNCTION_PASS("dse", DSEPass())
FUNCTION_PASS("early-cse", EarlyCSEPass())
-FUNCTION_PASS("gvn-hoist", GVNHoistPass())
FUNCTION_PASS("instcombine", InstCombinePass())
FUNCTION_PASS("invalidate<all>", InvalidateAllAnalysesPass())
FUNCTION_PASS("float2int", Float2IntPass())
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index bf63a11649a..2a209b34ccf 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -199,7 +199,6 @@ void PassManagerBuilder::populateFunctionPassManager(
FPM.add(createCFGSimplificationPass());
FPM.add(createSROAPass());
FPM.add(createEarlyCSEPass());
- FPM.add(createGVNHoistPass());
FPM.add(createLowerExpectIntrinsicPass());
}
diff --git a/llvm/lib/Transforms/Scalar/CMakeLists.txt b/llvm/lib/Transforms/Scalar/CMakeLists.txt
index 9f04344b8b0..ac162039037 100644
--- a/llvm/lib/Transforms/Scalar/CMakeLists.txt
+++ b/llvm/lib/Transforms/Scalar/CMakeLists.txt
@@ -12,7 +12,6 @@ add_llvm_library(LLVMScalarOpts
Float2Int.cpp
GuardWidening.cpp
GVN.cpp
- GVNHoist.cpp
InductiveRangeCheckElimination.cpp
IndVarSimplify.cpp
JumpThreading.cpp
diff --git a/llvm/lib/Transforms/Scalar/GVNHoist.cpp b/llvm/lib/Transforms/Scalar/GVNHoist.cpp
deleted file mode 100644
index c245efcf385..00000000000
--- a/llvm/lib/Transforms/Scalar/GVNHoist.cpp
+++ /dev/null
@@ -1,740 +0,0 @@
-//===- GVNHoist.cpp - Hoist scalar and load expressions -------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass hoists expressions from branches to a common dominator. It uses
-// GVN (global value numbering) to discover expressions computing the same
-// values. The primary goal is to reduce the code size, and in some
-// cases reduce critical path (by exposing more ILP).
-// Hoisting may affect the performance in some cases. To mitigate that, hoisting
-// is disabled in the following cases.
-// 1. Scalars across calls.
-// 2. geps when corresponding load/store cannot be hoisted.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Scalar/GVN.h"
-#include "llvm/Transforms/Utils/MemorySSA.h"
-#include <functional>
-#include <unordered_map>
-#include <vector>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "gvn-hoist"
-
-STATISTIC(NumHoisted, "Number of instructions hoisted");
-STATISTIC(NumRemoved, "Number of instructions removed");
-STATISTIC(NumLoadsHoisted, "Number of loads hoisted");
-STATISTIC(NumLoadsRemoved, "Number of loads removed");
-STATISTIC(NumStoresHoisted, "Number of stores hoisted");
-STATISTIC(NumStoresRemoved, "Number of stores removed");
-STATISTIC(NumCallsHoisted, "Number of calls hoisted");
-STATISTIC(NumCallsRemoved, "Number of calls removed");
-
-static cl::opt<int>
- MaxHoistedThreshold("gvn-max-hoisted", cl::Hidden, cl::init(-1),
- cl::desc("Max number of instructions to hoist "
- "(default unlimited = -1)"));
-static cl::opt<int> MaxNumberOfBBSInPath(
- "gvn-hoist-max-bbs", cl::Hidden, cl::init(4),
- cl::desc("Max number of basic blocks on the path between "
- "hoisting locations (default = 4, unlimited = -1)"));
-
-static int HoistedCtr = 0;
-
-namespace {
-
-// Provides a sorting function based on the execution order of two instructions.
-struct SortByDFSIn {
-private:
- DenseMap<const BasicBlock *, unsigned> &DFSNumber;
-
-public:
- SortByDFSIn(DenseMap<const BasicBlock *, unsigned> &D) : DFSNumber(D) {}
-
- // Returns true when A executes before B.
- bool operator()(const Instruction *A, const Instruction *B) const {
- assert(A != B);
- const BasicBlock *BA = A->getParent();
- const BasicBlock *BB = B->getParent();
- unsigned NA = DFSNumber[BA];
- unsigned NB = DFSNumber[BB];
- if (NA < NB)
- return true;
- if (NA == NB) {
- // Sort them in the order they occur in the same basic block.
- BasicBlock::const_iterator AI(A), BI(B);
- return std::distance(AI, BI) < 0;
- }
- return false;
- }
-};
-
-// A map from a VN (value number) to all the instructions with that VN.
-typedef DenseMap<unsigned, SmallVector<Instruction *, 4>> VNtoInsns;
-
-// Records all scalar instructions candidate for code hoisting.
-class InsnInfo {
- VNtoInsns VNtoScalars;
-
-public:
- // Inserts I and its value number in VNtoScalars.
- void insert(Instruction *I, GVN::ValueTable &VN) {
- // Scalar instruction.
- unsigned V = VN.lookupOrAdd(I);
- VNtoScalars[V].push_back(I);
- }
-
- const VNtoInsns &getVNTable() const { return VNtoScalars; }
-};
-
-// Records all load instructions candidate for code hoisting.
-class LoadInfo {
- VNtoInsns VNtoLoads;
-
-public:
- // Insert Load and the value number of its memory address in VNtoLoads.
- void insert(LoadInst *Load, GVN::ValueTable &VN) {
- if (Load->isSimple()) {
- unsigned V = VN.lookupOrAdd(Load->getPointerOperand());
- VNtoLoads[V].push_back(Load);
- }
- }
-
- const VNtoInsns &getVNTable() const { return VNtoLoads; }
-};
-
-// Records all store instructions candidate for code hoisting.
-class StoreInfo {
- VNtoInsns VNtoStores;
-
-public:
- // Insert the Store and a hash number of the store address and the stored
- // value in VNtoStores.
- void insert(StoreInst *Store, GVN::ValueTable &VN) {
- if (!Store->isSimple())
- return;
- // Hash the store address and the stored value.
- Value *Ptr = Store->getPointerOperand();
- Value *Val = Store->getValueOperand();
- VNtoStores[hash_combine(VN.lookupOrAdd(Ptr), VN.lookupOrAdd(Val))]
- .push_back(Store);
- }
-
- const VNtoInsns &getVNTable() const { return VNtoStores; }
-};
-
-// Records all call instructions candidate for code hoisting.
-class CallInfo {
- VNtoInsns VNtoCallsScalars;
- VNtoInsns VNtoCallsLoads;
- VNtoInsns VNtoCallsStores;
-
-public:
- // Insert Call and its value numbering in one of the VNtoCalls* containers.
- void insert(CallInst *Call, GVN::ValueTable &VN) {
- // A call that doesNotAccessMemory is handled as a Scalar,
- // onlyReadsMemory will be handled as a Load instruction,
- // all other calls will be handled as stores.
- unsigned V = VN.lookupOrAdd(Call);
-
- if (Call->doesNotAccessMemory())
- VNtoCallsScalars[V].push_back(Call);
- else if (Call->onlyReadsMemory())
- VNtoCallsLoads[V].push_back(Call);
- else
- VNtoCallsStores[V].push_back(Call);
- }
-
- const VNtoInsns &getScalarVNTable() const { return VNtoCallsScalars; }
-
- const VNtoInsns &getLoadVNTable() const { return VNtoCallsLoads; }
-
- const VNtoInsns &getStoreVNTable() const { return VNtoCallsStores; }
-};
-
-typedef DenseMap<const BasicBlock *, bool> BBSideEffectsSet;
-typedef SmallVector<Instruction *, 4> SmallVecInsn;
-typedef SmallVectorImpl<Instruction *> SmallVecImplInsn;
-
-// This pass hoists common computations across branches sharing common
-// dominator. The primary goal is to reduce the code size, and in some
-// cases reduce critical path (by exposing more ILP).
-class GVNHoistLegacyPassImpl {
-public:
- GVN::ValueTable VN;
- DominatorTree *DT;
- AliasAnalysis *AA;
- MemoryDependenceResults *MD;
- DenseMap<const BasicBlock *, unsigned> DFSNumber;
- BBSideEffectsSet BBSideEffects;
- MemorySSA *MSSA;
- enum InsKind { Unknown, Scalar, Load, Store };
-
- GVNHoistLegacyPassImpl(DominatorTree *Dt, AliasAnalysis *Aa,
- MemoryDependenceResults *Md)
- : DT(Dt), AA(Aa), MD(Md) {}
-
- // Return true when there are exception handling in BB.
- bool hasEH(const BasicBlock *BB) {
- auto It = BBSideEffects.find(BB);
- if (It != BBSideEffects.end())
- return It->second;
-
- if (BB->isEHPad() || BB->hasAddressTaken()) {
- BBSideEffects[BB] = true;
- return true;
- }
-
- if (BB->getTerminator()->mayThrow()) {
- BBSideEffects[BB] = true;
- return true;
- }
-
- BBSideEffects[BB] = false;
- return false;
- }
-
- // Return true when all paths from A to the end of the function pass through
- // either B or C.
- bool hoistingFromAllPaths(const BasicBlock *A, const BasicBlock *B,
- const BasicBlock *C) {
- // We fully copy the WL in order to be able to remove items from it.
- SmallPtrSet<const BasicBlock *, 2> WL;
- WL.insert(B);
- WL.insert(C);
-
- for (auto It = df_begin(A), E = df_end(A); It != E;) {
- // There exists a path from A to the exit of the function if we are still
- // iterating in DF traversal and we removed all instructions from the work
- // list.
- if (WL.empty())
- return false;
-
- const BasicBlock *BB = *It;
- if (WL.erase(BB)) {
- // Stop DFS traversal when BB is in the work list.
- It.skipChildren();
- continue;
- }
-
- // Check for end of function, calls that do not return, etc.
- if (!isGuaranteedToTransferExecutionToSuccessor(BB->getTerminator()))
- return false;
-
- // Increment DFS traversal when not skipping children.
- ++It;
- }
-
- return true;
- }
-
- // Each element of a hoisting list contains the basic block where to hoist and
- // a list of instructions to be hoisted.
- typedef std::pair<BasicBlock *, SmallVecInsn> HoistingPointInfo;
- typedef SmallVector<HoistingPointInfo, 4> HoistingPointList;
-
- // Return true when there are users of A in one of the BBs of Paths.
- bool hasMemoryUse(MemoryAccess *A, const BasicBlock *PBB) {
- Value::user_iterator UI = A->user_begin();
- Value::user_iterator UE = A->user_end();
- const BasicBlock *BBA = A->getBlock();
- for (; UI != UE; ++UI)
- if (MemoryAccess *UM = dyn_cast<MemoryAccess>(*UI)) {
- if (PBB == BBA)
- if (MSSA->locallyDominates(UM, A))
- return true;
- if (PBB == UM->getBlock())
- return true;
- }
- return false;
- }
-
- // Check whether it is possible to hoist in between NewHoistPt and BBInsn.
- bool safeToHoist(const BasicBlock *NewHoistPt, const BasicBlock *BBInsn,
- InsKind K, int &NBBsOnAllPaths, MemoryAccess *MemdefInsn,
- BasicBlock *BBMemdefInsn, MemoryAccess *MemdefFirst,
- BasicBlock *BBMemdefFirst) {
- assert(DT->dominates(NewHoistPt, BBInsn) && "Invalid path");
-
- // Record in Paths all basic blocks reachable in depth-first iteration on
- // the inverse CFG from BBInsn to NewHoistPt. These blocks are all the
- // blocks that may be executed between the execution of NewHoistPt and
- // BBInsn. Hoisting an expression from BBInsn into NewHoistPt has to be safe
- // on all execution paths.
- for (auto I = idf_begin(BBInsn), E = idf_end(BBInsn); I != E;) {
- if (*I == NewHoistPt) {
- // Stop traversal when reaching NewHoistPt.
- I.skipChildren();
- continue;
- }
-
- // The safety checks for BBInsn will be handled separately.
- if (*I != BBInsn) {
- // Stop gathering blocks when it is not possible to hoist.
- if (hasEH(*I))
- return false;
-
- // Check that we do not move a store past loads.
- if (K == InsKind::Store) {
- if (DT->dominates(BBMemdefInsn, NewHoistPt))
- if (hasMemoryUse(MemdefInsn, *I))
- return false;
-
- if (DT->dominates(BBMemdefFirst, NewHoistPt))
- if (hasMemoryUse(MemdefFirst, *I))
- return false;
- }
- }
- ++NBBsOnAllPaths;
- ++I;
- }
-
- // Check whether there are too many blocks on the hoisting path.
- if (MaxNumberOfBBSInPath != -1 && NBBsOnAllPaths >= MaxNumberOfBBSInPath)
- return false;
-
- return true;
- }
-
- // Return true when it is safe to hoist an instruction Insn to NewHoistPt and
- // move the insertion point from HoistPt to NewHoistPt.
- bool safeToHoist(const BasicBlock *NewHoistPt, const BasicBlock *HoistPt,
- const Instruction *Insn, const Instruction *First, InsKind K,
- int &NBBsOnAllPaths) {
- if (hasEH(HoistPt))
- return false;
-
- const BasicBlock *BBInsn = Insn->getParent();
- // When HoistPt already contains an instruction to be hoisted, the
- // expression is needed on all paths.
-
- // Check that the hoisted expression is needed on all paths: it is unsafe
- // to hoist loads to a place where there may be a path not loading from
- // the same address: for instance there may be a branch on which the
- // address of the load may not be initialized. FIXME: at -Oz we may want
- // to hoist scalars to a place where they are partially needed.
- if (BBInsn != NewHoistPt &&
- !hoistingFromAllPaths(NewHoistPt, HoistPt, BBInsn))
- return false;
-
- MemoryAccess *MemdefInsn = nullptr;
- MemoryAccess *MemdefFirst = nullptr;
- BasicBlock *BBMemdefInsn = nullptr;
- BasicBlock *BBMemdefFirst = nullptr;
-
- if (K != InsKind::Scalar) {
- // For loads and stores, we check for dependences on the Memory SSA.
- MemdefInsn = cast<MemoryUseOrDef>(MSSA->getMemoryAccess(Insn))
- ->getDefiningAccess();
- BBMemdefInsn = MemdefInsn->getBlock();
-
- if (DT->properlyDominates(NewHoistPt, BBMemdefInsn))
- // Cannot move Insn past BBMemdefInsn to NewHoistPt.
- return false;
-
- MemdefFirst = cast<MemoryUseOrDef>(MSSA->getMemoryAccess(First))
- ->getDefiningAccess();
- BBMemdefFirst = MemdefFirst->getBlock();
-
- if (DT->properlyDominates(NewHoistPt, BBMemdefFirst))
- // Cannot move First past BBMemdefFirst to NewHoistPt.
- return false;
- }
-
- // Check for unsafe hoistings due to side effects.
- if (!safeToHoist(NewHoistPt, HoistPt, K, NBBsOnAllPaths, MemdefInsn,
- BBMemdefInsn, MemdefFirst, BBMemdefFirst) ||
- !safeToHoist(NewHoistPt, BBInsn, K, NBBsOnAllPaths, MemdefInsn,
- BBMemdefInsn, MemdefFirst, BBMemdefFirst))
- return false;
-
- // Safe to hoist scalars.
- if (K == InsKind::Scalar)
- return true;
-
- if (DT->properlyDominates(BBMemdefInsn, NewHoistPt) &&
- DT->properlyDominates(BBMemdefFirst, NewHoistPt))
- return true;
-
- const BasicBlock *BBFirst = First->getParent();
- if (BBInsn == BBFirst)
- return false;
-
- assert(BBMemdefInsn == NewHoistPt || BBMemdefFirst == NewHoistPt);
-
- if (BBInsn != NewHoistPt && BBFirst != NewHoistPt)
- return true;
-
- if (BBInsn == NewHoistPt) {
- if (DT->properlyDominates(BBMemdefFirst, NewHoistPt))
- return true;
- assert(BBInsn == BBMemdefFirst);
- if (MSSA->locallyDominates(MSSA->getMemoryAccess(Insn), MemdefFirst))
- return false;
- return true;
- }
-
- if (BBFirst == NewHoistPt) {
- if (DT->properlyDominates(BBMemdefInsn, NewHoistPt))
- return true;
- assert(BBFirst == BBMemdefInsn);
- if (MSSA->locallyDominates(MSSA->getMemoryAccess(First), MemdefInsn))
- return false;
- return true;
- }
-
- // No side effects: it is safe to hoist.
- return true;
- }
-
- // Partition InstructionsToHoist into a set of candidates which can share a
- // common hoisting point. The partitions are collected in HPL. IsScalar is
- // true when the instructions in InstructionsToHoist are scalars. IsLoad is
- // true when the InstructionsToHoist are loads, false when they are stores.
- void partitionCandidates(SmallVecImplInsn &InstructionsToHoist,
- HoistingPointList &HPL, InsKind K) {
- // No need to sort for two instructions.
- if (InstructionsToHoist.size() > 2) {
- SortByDFSIn Pred(DFSNumber);
- std::sort(InstructionsToHoist.begin(), InstructionsToHoist.end(), Pred);
- }
-
- // Create a work list of all the BB of the Insns to be hoisted.
- SmallPtrSet<BasicBlock *, 4> WL;
- SmallVecImplInsn::iterator II = InstructionsToHoist.begin();
- SmallVecImplInsn::iterator Start = II;
- BasicBlock *HoistPt = (*II)->getParent();
- WL.insert((*II)->getParent());
- int NBBsOnAllPaths = 0;
-
- for (++II; II != InstructionsToHoist.end(); ++II) {
- Instruction *Insn = *II;
- BasicBlock *BB = Insn->getParent();
- BasicBlock *NewHoistPt = DT->findNearestCommonDominator(HoistPt, BB);
- WL.insert(BB);
- if (safeToHoist(NewHoistPt, HoistPt, Insn, *Start, K, NBBsOnAllPaths)) {
- // Extend HoistPt to NewHoistPt.
- HoistPt = NewHoistPt;
- continue;
- }
- // Not safe to hoist: save the previous work list and start over from BB.
- if (std::distance(Start, II) > 1)
- HPL.push_back(std::make_pair(HoistPt, SmallVecInsn(Start, II)));
- else
- WL.clear();
-
- // We start over to compute HoistPt from BB.
- Start = II;
- HoistPt = BB;
- NBBsOnAllPaths = 0;
- }
-
- // Save the last partition.
- if (std::distance(Start, II) > 1)
- HPL.push_back(std::make_pair(HoistPt, SmallVecInsn(Start, II)));
- }
-
- // Initialize HPL from Map.
- void computeInsertionPoints(const VNtoInsns &Map, HoistingPointList &HPL,
- InsKind K) {
- for (VNtoInsns::const_iterator It = Map.begin(); It != Map.end(); ++It) {
- if (MaxHoistedThreshold != -1 && ++HoistedCtr > MaxHoistedThreshold)
- return;
-
- const SmallVecInsn &V = It->second;
- if (V.size() < 2)
- continue;
-
- // Compute the insertion point and the list of expressions to be hoisted.
- SmallVecInsn InstructionsToHoist;
- for (auto I : V)
- if (!hasEH(I->getParent()))
- InstructionsToHoist.push_back(I);
-
- if (InstructionsToHoist.size())
- partitionCandidates(InstructionsToHoist, HPL, K);
- }
- }
-
- // Return true when all operands of Instr are available at insertion point
- // HoistPt. When limiting the number of hoisted expressions, one could hoist
- // a load without hoisting its access function. So before hoisting any
- // expression, make sure that all its operands are available at insert point.
- bool allOperandsAvailable(const Instruction *I,
- const BasicBlock *HoistPt) const {
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- const Value *Op = I->getOperand(i);
- const Instruction *Inst = dyn_cast<Instruction>(Op);
- if (Inst && !DT->dominates(Inst->getParent(), HoistPt))
- return false;
- }
-
- return true;
- }
-
- Instruction *firstOfTwo(Instruction *I, Instruction *J) const {
- for (Instruction &I1 : *I->getParent())
- if (&I1 == I || &I1 == J)
- return &I1;
- llvm_unreachable("Both I and J must be from same BB");
- }
-
- // Replace the use of From with To in Insn.
- void replaceUseWith(Instruction *Insn, Value *From, Value *To) const {
- for (Value::use_iterator UI = From->use_begin(), UE = From->use_end();
- UI != UE;) {
- Use &U = *UI++;
- if (U.getUser() == Insn) {
- U.set(To);
- return;
- }
- }
- llvm_unreachable("should replace exactly once");
- }
-
- bool makeOperandsAvailable(Instruction *Repl, BasicBlock *HoistPt) const {
- // Check whether the GEP of a ld/st can be synthesized at HoistPt.
- Instruction *Gep = nullptr;
- Instruction *Val = nullptr;
- if (LoadInst *Ld = dyn_cast<LoadInst>(Repl))
- Gep = dyn_cast<Instruction>(Ld->getPointerOperand());
- if (StoreInst *St = dyn_cast<StoreInst>(Repl)) {
- Gep = dyn_cast<Instruction>(St->getPointerOperand());
- Val = dyn_cast<Instruction>(St->getValueOperand());
- }
-
- if (!Gep || !isa<GetElementPtrInst>(Gep))
- return false;
-
- // Check whether we can compute the Gep at HoistPt.
- if (!allOperandsAvailable(Gep, HoistPt))
- return false;
-
- // Also check that the stored value is available.
- if (Val && !allOperandsAvailable(Val, HoistPt))
- return false;
-
- // Copy the gep before moving the ld/st.
- Instruction *ClonedGep = Gep->clone();
- ClonedGep->insertBefore(HoistPt->getTerminator());
- replaceUseWith(Repl, Gep, ClonedGep);
-
- // Also copy Val when it is a gep: geps are not hoisted by default.
- if (Val && isa<GetElementPtrInst>(Val)) {
- Instruction *ClonedVal = Val->clone();
- ClonedVal->insertBefore(HoistPt->getTerminator());
- replaceUseWith(Repl, Val, ClonedVal);
- }
-
- return true;
- }
-
- std::pair<unsigned, unsigned> hoist(HoistingPointList &HPL) {
- unsigned NI = 0, NL = 0, NS = 0, NC = 0, NR = 0;
- for (const HoistingPointInfo &HP : HPL) {
- // Find out whether we already have one of the instructions in HoistPt,
- // in which case we do not have to move it.
- BasicBlock *HoistPt = HP.first;
- const SmallVecInsn &InstructionsToHoist = HP.second;
- Instruction *Repl = nullptr;
- for (Instruction *I : InstructionsToHoist)
- if (I->getParent() == HoistPt) {
- // If there are two instructions in HoistPt to be hoisted in place:
- // update Repl to be the first one, such that we can rename the uses
- // of the second based on the first.
- Repl = !Repl ? I : firstOfTwo(Repl, I);
- }
-
- if (Repl) {
- // Repl is already in HoistPt: it remains in place.
- assert(allOperandsAvailable(Repl, HoistPt) &&
- "instruction depends on operands that are not available");
- } else {
- // When we do not find Repl in HoistPt, select the first in the list
- // and move it to HoistPt.
- Repl = InstructionsToHoist.front();
-
- // We can move Repl in HoistPt only when all operands are available.
- // The order in which hoistings are done may influence the availability
- // of operands.
- if (!allOperandsAvailable(Repl, HoistPt) &&
- !makeOperandsAvailable(Repl, HoistPt))
- continue;
- Repl->moveBefore(HoistPt->getTerminator());
- }
-
- if (isa<LoadInst>(Repl))
- ++NL;
- else if (isa<StoreInst>(Repl))
- ++NS;
- else if (isa<CallInst>(Repl))
- ++NC;
- else // Scalar
- ++NI;
-
- // Remove and rename all other instructions.
- for (Instruction *I : InstructionsToHoist)
- if (I != Repl) {
- ++NR;
- if (isa<LoadInst>(Repl))
- ++NumLoadsRemoved;
- else if (isa<StoreInst>(Repl))
- ++NumStoresRemoved;
- else if (isa<CallInst>(Repl))
- ++NumCallsRemoved;
- I->replaceAllUsesWith(Repl);
- I->eraseFromParent();
- }
- }
-
- NumHoisted += NL + NS + NC + NI;
- NumRemoved += NR;
- NumLoadsHoisted += NL;
- NumStoresHoisted += NS;
- NumCallsHoisted += NC;
- return {NI, NL + NC + NS};
- }
-
- // Hoist all expressions. Returns Number of scalars hoisted
- // and number of non-scalars hoisted.
- std::pair<unsigned, unsigned> hoistExpressions(Function &F) {
- InsnInfo II;
- LoadInfo LI;
- StoreInfo SI;
- CallInfo CI;
- const bool OptForMinSize = F.optForMinSize();
- for (BasicBlock *BB : depth_first(&F.getEntryBlock())) {
- for (Instruction &I1 : *BB) {
- if (LoadInst *Load = dyn_cast<LoadInst>(&I1))
- LI.insert(Load, VN);
- else if (StoreInst *Store = dyn_cast<StoreInst>(&I1))
- SI.insert(Store, VN);
- else if (CallInst *Call = dyn_cast<CallInst>(&I1)) {
- if (IntrinsicInst *Intr = dyn_cast<IntrinsicInst>(Call)) {
- if (isa<DbgInfoIntrinsic>(Intr) ||
- Intr->getIntrinsicID() == Intrinsic::assume)
- continue;
- }
- if (Call->mayHaveSideEffects()) {
- if (!OptForMinSize)
- break;
- // We may continue hoisting across calls which write to memory.
- if (Call->mayThrow())
- break;
- }
- CI.insert(Call, VN);
- } else if (OptForMinSize || !isa<GetElementPtrInst>(&I1))
- // Do not hoist scalars past calls that may write to memory because
- // that could result in spills later. geps are handled separately.
- // TODO: We can relax this for targets like AArch64 as they have more
- // registers than X86.
- II.insert(&I1, VN);
- }
- }
-
- HoistingPointList HPL;
- computeInsertionPoints(II.getVNTable(), HPL, InsKind::Scalar);
- computeInsertionPoints(LI.getVNTable(), HPL, InsKind::Load);
- computeInsertionPoints(SI.getVNTable(), HPL, InsKind::Store);
- computeInsertionPoints(CI.getScalarVNTable(), HPL, InsKind::Scalar);
- computeInsertionPoints(CI.getLoadVNTable(), HPL, InsKind::Load);
- computeInsertionPoints(CI.getStoreVNTable(), HPL, InsKind::Store);
- return hoist(HPL);
- }
-
- bool run(Function &F) {
- VN.setDomTree(DT);
- VN.setAliasAnalysis(AA);
- VN.setMemDep(MD);
- bool Res = false;
-
- unsigned I = 0;
- for (const BasicBlock *BB : depth_first(&F.getEntryBlock()))
- DFSNumber.insert(std::make_pair(BB, ++I));
-
- // FIXME: use lazy evaluation of VN to avoid the fix-point computation.
- while (1) {
- // FIXME: only compute MemorySSA once. We need to update the analysis in
- // the same time as transforming the code.
- MemorySSA M(F, AA, DT);
- MSSA = &M;
-
- auto HoistStat = hoistExpressions(F);
- if (HoistStat.first + HoistStat.second == 0) {
- return Res;
- }
- if (HoistStat.second > 0) {
- // To address a limitation of the current GVN, we need to rerun the
- // hoisting after we hoisted loads in order to be able to hoist all
- // scalars dependent on the hoisted loads. Same for stores.
- VN.clear();
- }
- Res = true;
- }
-
- return Res;
- }
-};
-
-class GVNHoistLegacyPass : public FunctionPass {
-public:
- static char ID;
-
- GVNHoistLegacyPass() : FunctionPass(ID) {
- initializeGVNHoistLegacyPassPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override {
- auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
- auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
- auto &MD = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();
-
- GVNHoistLegacyPassImpl G(&DT, &AA, &MD);
- return G.run(F);
- }
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<DominatorTreeWrapperPass>();
- AU.addRequired<AAResultsWrapperPass>();
- AU.addRequired<MemoryDependenceWrapperPass>();
- AU.addPreserved<DominatorTreeWrapperPass>();
- }
-};
-} // namespace
-
-PreservedAnalyses GVNHoistPass::run(Function &F,
- AnalysisManager<Function> &AM) {
- DominatorTree &DT = AM.getResult<DominatorTreeAnalysis>(F);
- AliasAnalysis &AA = AM.getResult<AAManager>(F);
- MemoryDependenceResults &MD = AM.getResult<MemoryDependenceAnalysis>(F);
-
- GVNHoistLegacyPassImpl G(&DT, &AA, &MD);
- if (!G.run(F))
- return PreservedAnalyses::all();
-
- PreservedAnalyses PA;
- PA.preserve<DominatorTreeAnalysis>();
- return PA;
-}
-
-char GVNHoistLegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(GVNHoistLegacyPass, "gvn-hoist",
- "Early GVN Hoisting of Expressions", false, false)
-INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_END(GVNHoistLegacyPass, "gvn-hoist",
- "Early GVN Hoisting of Expressions", false, false)
-
-FunctionPass *llvm::createGVNHoistPass() { return new GVNHoistLegacyPass(); }
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 6f1f75d06ce..baac4545cb5 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -44,7 +44,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
initializeGuardWideningLegacyPassPass(Registry);
initializeGVNLegacyPassPass(Registry);
initializeEarlyCSELegacyPassPass(Registry);
- initializeGVNHoistLegacyPassPass(Registry);
initializeFlattenCFGPassPass(Registry);
initializeInductiveRangeCheckEliminationPass(Registry);
initializeIndVarSimplifyLegacyPassPass(Registry);
@@ -237,10 +236,6 @@ void LLVMAddEarlyCSEPass(LLVMPassManagerRef PM) {
unwrap(PM)->add(createEarlyCSEPass());
}
-void LLVMAddGVNHoistLegacyPass(LLVMPassManagerRef PM) {
- unwrap(PM)->add(createGVNHoistPass());
-}
-
void LLVMAddTypeBasedAliasAnalysisPass(LLVMPassManagerRef PM) {
unwrap(PM)->add(createTypeBasedAAWrapperPass());
}
OpenPOWER on IntegriCloud