[llvm] r245025 - Add support for cross block dse.
David Majnemer via llvm-commits
llvm-commits at lists.llvm.org
Sun Aug 16 00:13:11 PDT 2015
I've reverted this in r245172, it seems to have caused PR24469.
On Fri, Aug 14, 2015 at 12:39 PM, NAKAMURA Takumi via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Seems nondeteministic behavior. Investigating.
> See, http://bb.pgr.jp/builders/clang-3stage-i686-linux/builds/2935
>
> On Fri, Aug 14, 2015 at 1:18 PM Karthik Bhat via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: karthik
>> Date: Thu Aug 13 23:17:23 2015
>> New Revision: 245025
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=245025&view=rev
>> Log:
>> Add support for cross block dse.
>> This patch enables dead stroe elimination across basicblocks.
>>
>> Example:
>> define void @test_02(i32 %N) {
>> %1 = alloca i32
>> store i32 %N, i32* %1
>> store i32 10, i32* @x
>> %2 = load i32, i32* %1
>> %3 = icmp ne i32 %2, 0
>> br i1 %3, label %4, label %5
>>
>> ; <label>:4
>> store i32 5, i32* @x
>> br label %7
>>
>> ; <label>:5
>> %6 = load i32, i32* @x
>> store i32 %6, i32* @y
>> br label %7
>>
>> ; <label>:7
>> store i32 15, i32* @x
>> ret void
>> }
>> In the above example dead store "store i32 5, i32* @x" is now eliminated.
>>
>> Differential Revision: http://reviews.llvm.org/D11143
>>
>>
>> Added:
>> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
>>
>> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll
>> Modified:
>> llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
>>
>> Modified: llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp?rev=245025&r1=245024&r2=245025&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp (original)
>> +++ llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp Thu Aug 13
>> 23:17:23 2015
>> @@ -16,13 +16,16 @@
>>
>> //===----------------------------------------------------------------------===//
>>
>> #include "llvm/Transforms/Scalar.h"
>> +#include "llvm/ADT/DenseSet.h"
>> #include "llvm/ADT/STLExtras.h"
>> #include "llvm/ADT/SetVector.h"
>> #include "llvm/ADT/Statistic.h"
>> #include "llvm/Analysis/AliasAnalysis.h"
>> #include "llvm/Analysis/CaptureTracking.h"
>> +#include "llvm/Analysis/CFG.h"
>> #include "llvm/Analysis/MemoryBuiltins.h"
>> #include "llvm/Analysis/MemoryDependenceAnalysis.h"
>> +#include "llvm/Analysis/PostDominators.h"
>> #include "llvm/Analysis/TargetLibraryInfo.h"
>> #include "llvm/Analysis/ValueTracking.h"
>> #include "llvm/IR/Constants.h"
>> @@ -42,6 +45,7 @@ using namespace llvm;
>>
>> STATISTIC(NumRedundantStores, "Number of redundant stores deleted");
>> STATISTIC(NumFastStores, "Number of stores deleted");
>> +STATISTIC(NumCrossBlockStores, "Number of cross block stores deleted");
>> STATISTIC(NumFastOther , "Number of other instrs removed");
>>
>> namespace {
>> @@ -49,12 +53,41 @@ namespace {
>> AliasAnalysis *AA;
>> MemoryDependenceAnalysis *MD;
>> DominatorTree *DT;
>> + PostDominatorTree *PDT;
>> const TargetLibraryInfo *TLI;
>> -
>> + SmallVector<SmallVector<StoreInst *, 8>, 16> Candidates;
>> + SetVector<StoreInst *> DeadStores;
>> + SmallVector<std::pair<const BasicBlock *, const BasicBlock *>, 32>
>> + BackEdges;
>> + DenseSet<std::pair<const BasicBlock *, const BasicBlock *>>
>> BackEdgesMap;
>> static char ID; // Pass identification, replacement for typeid
>> - DSE() : FunctionPass(ID), AA(nullptr), MD(nullptr), DT(nullptr) {
>> + DSE()
>> + : FunctionPass(ID), AA(nullptr), MD(nullptr), DT(nullptr),
>> + PDT(nullptr) {
>> initializeDSEPass(*PassRegistry::getPassRegistry());
>> }
>> + // Return all stores in a given BasicBlock.
>> + SmallVector<StoreInst *, 8> getStores(BasicBlock *BB) {
>> + SmallVector<StoreInst *, 8> VecStores;
>> + for (auto &BI : *BB) {
>> + if (StoreInst *SI = dyn_cast<StoreInst>(&BI))
>> + VecStores.push_back(SI);
>> + }
>> + return VecStores;
>> + }
>> +
>> + // Get dfs in/out on the PDT and populate Candidates store list which
>> + // is used to find potential dead stores for a given block
>> + void populateCandidateStores(Function &F) {
>> + for (auto &I : F) {
>> + DomTreeNode *DTNode = PDT->getNode(&I);
>> + if (!DTNode)
>> + continue;
>> + int DFSIn = DTNode->getDFSNumIn();
>> + SmallVector<StoreInst *, 8> VecStores = getStores(&I);
>> + Candidates[DFSIn] = VecStores;
>> + }
>> + }
>>
>> bool runOnFunction(Function &F) override {
>> if (skipOptnoneFunction(F))
>> @@ -64,7 +97,21 @@ namespace {
>> MD = &getAnalysis<MemoryDependenceAnalysis>();
>> DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
>> TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
>> -
>> + PDT = &getAnalysis<PostDominatorTree>();
>> + if (PDT->getRootNode()) {
>> + int Count = PDT->getRootNode()->getDFSNumOut();
>> + SmallVector<StoreInst *, 8> VecStores;
>> + Candidates.resize(Count + 1);
>> + Candidates.assign(Count + 1, VecStores);
>> +
>> + // If we have more than 1 block try to populate candidate store.
>> + if (Count > 1) {
>> + populateCandidateStores(F);
>> + FindFunctionBackedges(F, BackEdges);
>> + for (auto I : BackEdges)
>> + BackEdgesMap.insert(I);
>> + }
>> + }
>> bool Changed = false;
>> for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
>> // Only check non-dead blocks. Dead blocks may have strange
>> pointer
>> @@ -83,16 +130,23 @@ namespace {
>> void RemoveAccessedObjects(const MemoryLocation &LoadedLoc,
>> SmallSetVector<Value *, 16>
>> &DeadStackObjects,
>> const DataLayout &DL);
>> -
>> + void handleNonLocalStoreDeletion(StoreInst *SI);
>> + bool isSafeCandidateForDeletion(BasicBlock *SrcBlock, BasicBlock
>> *SinkBlock,
>> + StoreInst *SI);
>> + void DeleteDeadInstruction(Instruction *I, MemoryDependenceAnalysis
>> &MD,
>> + const TargetLibraryInfo &TLI,
>> + SmallSetVector<Value *, 16> *ValueSet =
>> nullptr);
>> void getAnalysisUsage(AnalysisUsage &AU) const override {
>> AU.setPreservesCFG();
>> AU.addRequired<DominatorTreeWrapperPass>();
>> AU.addRequired<AliasAnalysis>();
>> AU.addRequired<MemoryDependenceAnalysis>();
>> + AU.addRequired<PostDominatorTree>();
>> AU.addRequired<TargetLibraryInfoWrapperPass>();
>> AU.addPreserved<AliasAnalysis>();
>> AU.addPreserved<DominatorTreeWrapperPass>();
>> AU.addPreserved<MemoryDependenceAnalysis>();
>> + AU.addPreserved<PostDominatorTree>();
>> }
>> };
>> }
>> @@ -102,6 +156,7 @@ INITIALIZE_PASS_BEGIN(DSE, "dse", "Dead
>> INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
>> INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
>> INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
>> +INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
>> INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
>> INITIALIZE_PASS_END(DSE, "dse", "Dead Store Elimination", false, false)
>>
>> @@ -111,50 +166,6 @@ FunctionPass *llvm::createDeadStoreElimi
>> // Helper functions
>>
>> //===----------------------------------------------------------------------===//
>>
>> -/// DeleteDeadInstruction - Delete this instruction. Before we do, go
>> through
>> -/// and zero out all the operands of this instruction. If any of them
>> become
>> -/// dead, delete them and the computation tree that feeds them.
>> -///
>> -/// If ValueSet is non-null, remove any deleted instructions from it as
>> well.
>> -///
>> -static void DeleteDeadInstruction(Instruction *I,
>> - MemoryDependenceAnalysis &MD,
>> - const TargetLibraryInfo &TLI,
>> - SmallSetVector<Value*, 16> *ValueSet =
>> nullptr) {
>> - SmallVector<Instruction*, 32> NowDeadInsts;
>> -
>> - NowDeadInsts.push_back(I);
>> - --NumFastOther;
>> -
>> - // Before we touch this instruction, remove it from memdep!
>> - do {
>> - Instruction *DeadInst = NowDeadInsts.pop_back_val();
>> - ++NumFastOther;
>> -
>> - // This instruction is dead, zap it, in stages. Start by removing
>> it from
>> - // MemDep, which needs to know the operands and needs it to be in the
>> - // function.
>> - MD.removeInstruction(DeadInst);
>> -
>> - for (unsigned op = 0, e = DeadInst->getNumOperands(); op != e; ++op)
>> {
>> - Value *Op = DeadInst->getOperand(op);
>> - DeadInst->setOperand(op, nullptr);
>> -
>> - // If this operand just became dead, add it to the NowDeadInsts
>> list.
>> - if (!Op->use_empty()) continue;
>> -
>> - if (Instruction *OpI = dyn_cast<Instruction>(Op))
>> - if (isInstructionTriviallyDead(OpI, &TLI))
>> - NowDeadInsts.push_back(OpI);
>> - }
>> -
>> - DeadInst->eraseFromParent();
>> -
>> - if (ValueSet) ValueSet->remove(DeadInst);
>> - } while (!NowDeadInsts.empty());
>> -}
>> -
>> -
>> /// hasMemoryWrite - Does this instruction write some memory? This only
>> returns
>> /// true for things that we can analyze with other helpers below.
>> static bool hasMemoryWrite(Instruction *I, const TargetLibraryInfo &TLI)
>> {
>> @@ -527,10 +538,15 @@ bool DSE::runOnBasicBlock(BasicBlock &BB
>>
>> MemDepResult InstDep = MD->getDependency(Inst);
>>
>> - // Ignore any store where we can't find a local dependence.
>> - // FIXME: cross-block DSE would be fun. :)
>> - if (!InstDep.isDef() && !InstDep.isClobber())
>> + if (!InstDep.isDef() && !InstDep.isClobber() &&
>> !InstDep.isNonLocal())
>> continue;
>> + if (InstDep.isNonLocal()) {
>> + if (!PDT->getRootNode())
>> + continue;
>> + if (StoreInst *SI = dyn_cast<StoreInst>(Inst))
>> + handleNonLocalStoreDeletion(SI);
>> + continue;
>> + }
>>
>> // Figure out what location is being stored to.
>> MemoryLocation Loc = getLocForWrite(Inst, *AA);
>> @@ -704,6 +720,50 @@ static void FindUnconditionalPreds(Small
>> }
>> }
>>
>> +/// DeleteDeadInstruction - Delete this instruction. Before we do, go
>> through
>> +/// and zero out all the operands of this instruction. If any of them
>> become
>> +/// dead, delete them and the computation tree that feeds them.
>> +/// If ValueSet is non-null, remove any deleted instructions from it as
>> well.
>> +void DSE::DeleteDeadInstruction(Instruction *I, MemoryDependenceAnalysis
>> &MD,
>> + const TargetLibraryInfo &TLI,
>> + SmallSetVector<Value *, 16> *ValueSet) {
>> + SmallVector<Instruction *, 32> NowDeadInsts;
>> +
>> + NowDeadInsts.push_back(I);
>> + --NumFastOther;
>> +
>> + // Before we touch this instruction, remove it from memdep!
>> + do {
>> + Instruction *DeadInst = NowDeadInsts.pop_back_val();
>> + ++NumFastOther;
>> + if (StoreInst *SI = dyn_cast<StoreInst>(DeadInst))
>> + DeadStores.insert(SI);
>> +
>> + // This instruction is dead, zap it, in stages. Start by removing
>> it from
>> + // MemDep, which needs to know the operands and needs it to be in the
>> + // function.
>> + MD.removeInstruction(DeadInst);
>> +
>> + for (unsigned op = 0, e = DeadInst->getNumOperands(); op != e; ++op)
>> {
>> + Value *Op = DeadInst->getOperand(op);
>> + DeadInst->setOperand(op, nullptr);
>> +
>> + // If this operand just became dead, add it to the NowDeadInsts
>> list.
>> + if (!Op->use_empty())
>> + continue;
>> +
>> + if (Instruction *OpI = dyn_cast<Instruction>(Op))
>> + if (isInstructionTriviallyDead(OpI, &TLI))
>> + NowDeadInsts.push_back(OpI);
>> + }
>> +
>> + DeadInst->eraseFromParent();
>> +
>> + if (ValueSet)
>> + ValueSet->remove(DeadInst);
>> + } while (!NowDeadInsts.empty());
>> +}
>> +
>> /// HandleFree - Handle frees of entire structures whose dependency is a
>> store
>> /// to a field of that structure.
>> bool DSE::HandleFree(CallInst *F) {
>> @@ -931,3 +991,116 @@ void DSE::RemoveAccessedObjects(const Me
>> return !AA->isNoAlias(StackLoc, LoadedLoc);
>> });
>> }
>> +
>> +/// isSafeCandidateForDeletion- Check all paths from the SrcBlock till
>> +/// SinkBlock to see if Store 'SI' is safe to be remove.
>> +/// Returns true if the candidate store SI is safe to delete
>> +/// else returns false.
>> +bool DSE::isSafeCandidateForDeletion(BasicBlock *SrcBlock,
>> + BasicBlock *SinkBlock, StoreInst
>> *SI) {
>> + SmallVector<BasicBlock *, 16> WorkList;
>> + SmallPtrSet<BasicBlock *, 8> Visited;
>> + BasicBlock::iterator BBI(SI);
>> +
>> + // Check from the store till end of block and make sure we have no
>> references
>> + // to memory stored by this Store Instruction.
>> + for (auto BI = ++BBI, BE = SrcBlock->end(); BI != BE; ++BI) {
>> + Instruction *I = BI;
>> + StoreInst *CSI = dyn_cast<StoreInst>(I);
>> + if (CSI) {
>> + AliasResult R =
>> + AA->alias(MemoryLocation::get(SI), MemoryLocation::get(CSI));
>> + if (R == MustAlias)
>> + return true;
>> + } else {
>> + ModRefInfo Res = AA->getModRefInfo(I, MemoryLocation::get(SI));
>> + if (Res != MRI_NoModRef)
>> + return false;
>> + }
>> + }
>> +
>> + // Add successors of the block to stack and start DFS.
>> + for (succ_iterator I = succ_begin(SrcBlock), E = succ_end(SrcBlock); I
>> != E;
>> + ++I) {
>> + if (!Visited.insert(*I).second)
>> + continue;
>> + // A path with backedge may not be safe. Conservatively mark
>> + // this store unsafe.
>> + if (BackEdgesMap.count(std::make_pair(SrcBlock, *I)))
>> + return false;
>> + WorkList.push_back(*I);
>> + }
>> +
>> + while (!WorkList.empty()) {
>> + BasicBlock *B = WorkList.pop_back_val();
>> + auto BI = B->begin();
>> + auto BE = B->end();
>> + for (; BI != BE; ++BI) {
>> + Instruction *I = BI;
>> + StoreInst *CSI = dyn_cast<StoreInst>(I);
>> + if (CSI) {
>> + AliasResult R =
>> + AA->alias(MemoryLocation::get(SI), MemoryLocation::get(CSI));
>> + if (R == MustAlias)
>> + break;
>> + } else {
>> + ModRefInfo Res = AA->getModRefInfo(I, MemoryLocation::get(SI));
>> + if (Res != MRI_NoModRef)
>> + return false;
>> + }
>> + }
>> +
>> + // If we reached the sink node or we found a block which has a
>> stores that
>> + // overwrites the candidate block we need not look at their
>> successors.
>> + if (B == SinkBlock || BI != BE)
>> + continue;
>> +
>> + for (succ_iterator I = succ_begin(B), E = succ_end(B); I != E; ++I) {
>> + if (!Visited.insert(*I).second)
>> + continue;
>> + // A path with backedge may not be safe.Conservatively mark
>> + // this store unsafe.
>> + if (BackEdgesMap.count(std::make_pair(B, *I)))
>> + return false;
>> + WorkList.push_back(*I);
>> + }
>> + }
>> +
>> + return true;
>> +}
>> +
>> +/// handleNonLocalStoreDeletion - Handle non local dead store
>> elimination.
>> +/// This works by finding candidate stores using PDT and then running DFS
>> +/// from candidate store block checking all paths to make sure the store
>> is
>> +/// safe to delete.
>> +void DSE::handleNonLocalStoreDeletion(StoreInst *SI) {
>> + BasicBlock *BB = SI->getParent();
>> + Value *Pointer = SI->getPointerOperand();
>> + DomTreeNode *DTNode = PDT->getNode(BB);
>> + if (!DTNode)
>> + return;
>> +
>> + int DFSNumIn = DTNode->getDFSNumIn();
>> + int DFSNumOut = DTNode->getDFSNumOut();
>> + for (int i = DFSNumIn + 1; i < DFSNumOut; ++i) {
>> + for (auto &I : Candidates[i]) {
>> + StoreInst *CandidateSI = I;
>> + if (DeadStores.count(CandidateSI))
>> + continue;
>> + Value *MemPtr = CandidateSI->getPointerOperand();
>> + if (!MemPtr)
>> + continue;
>> + if (Pointer->getType() != MemPtr->getType())
>> + continue;
>> + AliasResult R =
>> + AA->alias(MemoryLocation::get(SI),
>> MemoryLocation::get(CandidateSI));
>> + if (R != MustAlias)
>> + continue;
>> + if (isSafeCandidateForDeletion(CandidateSI->getParent(), BB,
>> + CandidateSI)) {
>> + DeleteDeadInstruction(CandidateSI, *MD, *TLI);
>> + ++NumCrossBlockStores;
>> + }
>> + }
>> + }
>> +}
>>
>> Added: llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll?rev=245025&view=auto
>>
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
>> (added)
>> +++ llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
>> Thu Aug 13 23:17:23 2015
>> @@ -0,0 +1,76 @@
>> +; RUN: opt < %s -basicaa -dse -S | FileCheck %s
>> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> +
>> + at x = common global i32 0
>> + at y = common global i32 0
>> +
>> +define void @test_01(i32 %N) {
>> + %1 = alloca i32
>> + store i32 %N, i32* %1
>> + store i32 10, i32* @x
>> + %2 = load i32, i32* %1
>> + %3 = icmp ne i32 %2, 0
>> + br i1 %3, label %4, label %5
>> +
>> +; <label>:4
>> + store i32 5, i32* @x
>> + br label %5
>> +
>> +; <label>:5
>> + store i32 15, i32* @x
>> + ret void
>> +}
>> +; CHECK-LABEL: @test_01(
>> +; CHECK-NOT: store i32 10, i32* @x
>> +; CHECK-NOT: store i32 5, i32* @x
>> +; CHECK: store i32 15, i32* @x
>> +
>> +
>> +define void @test_02(i32 %N) {
>> + %1 = alloca i32
>> + store i32 %N, i32* %1
>> + store i32 10, i32* @x
>> + %2 = load i32, i32* %1
>> + %3 = icmp ne i32 %2, 0
>> + br i1 %3, label %4, label %5
>> +
>> +; <label>:4
>> + store i32 5, i32* @x
>> + br label %7
>> +
>> +; <label>:5
>> + %6 = load i32, i32* @x
>> + store i32 %6, i32* @y
>> + br label %7
>> +
>> +; <label>:7
>> + store i32 15, i32* @x
>> + ret void
>> +}
>> +; CHECK-LABEL: @test_02(
>> +; CHECK: store i32 10, i32* @x
>> +; CHECK-NOT: store i32 5, i32* @x
>> +; CHECK: store i32 %6, i32* @y
>> +
>> +
>> +define void @test_03(i32 %N) #0 {
>> + %1 = alloca i32
>> + store i32 %N, i32* %1
>> + store i32 10, i32* @x
>> + %2 = load i32, i32* %1
>> + %3 = icmp ne i32 %2, 0
>> + br i1 %3, label %4, label %6
>> +
>> +; <label>:4 ; preds = %0
>> + %5 = load i32, i32* @x
>> + store i32 %5, i32* @y
>> + br label %6
>> +
>> +; <label>:6 ; preds = %4, %0
>> + store i32 15, i32* @x
>> + ret void
>> +}
>> +; CHECK-LABEL: @test_03(
>> +; CHECK: store i32 10, i32* @x
>> +; CHECK: store i32 %5, i32* @y
>> +; CHECK: store i32 15, i32* @x
>>
>> Added:
>> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll?rev=245025&view=auto
>>
>> ==============================================================================
>> ---
>> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll
>> (added)
>> +++
>> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll Thu
>> Aug 13 23:17:23 2015
>> @@ -0,0 +1,104 @@
>> +; RUN: opt < %s -basicaa -dse -S | FileCheck %s
>> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> +
>> + at A = common global [100 x i32] zeroinitializer, align 16
>> + at x = common global i32 0
>> +
>> +; Negative Test case-
>> +;void foo(int N) {
>> +; A[0] = N;
>> +; for(int i=0;i<N;++i)
>> +; A[i]+=i;
>> +; A[0] = 10;
>> +;}
>> +;; Stores should not be optimized away.
>> +
>> +define void @test_01(i32 %N) #0 {
>> + %1 = alloca i32
>> + %i = alloca i32
>> + store i32 %N, i32* %1
>> + %2 = load i32, i32* %1
>> + store i32 %2, i32* getelementptr inbounds ([100 x i32], [100 x i32]*
>> @A, i32 0, i64 0)
>> + store i32 0, i32* %i
>> + br label %3
>> +
>> +; <label>:3 ; preds = %14, %0
>> + %4 = load i32, i32* %i
>> + %5 = load i32, i32* %1
>> + %6 = icmp slt i32 %4, %5
>> + br i1 %6, label %7, label %17
>> +
>> +; <label>:7 ; preds = %3
>> + %8 = load i32, i32* %i
>> + %9 = load i32, i32* %i
>> + %10 = sext i32 %9 to i64
>> + %11 = getelementptr inbounds [100 x i32], [100 x i32]* @A, i32 0, i64
>> %10
>> + %12 = load i32, i32* %11
>> + %13 = add nsw i32 %12, %8
>> + store i32 %13, i32* %11
>> + br label %14
>> +
>> +; <label>:14 ; preds = %7
>> + %15 = load i32, i32* %i
>> + %16 = add nsw i32 %15, 1
>> + store i32 %16, i32* %i
>> + br label %3
>> +
>> +; <label>:17 ; preds = %3
>> + store i32 10, i32* getelementptr inbounds ([100 x i32], [100 x i32]*
>> @A, i32 0, i64 0)
>> + ret void
>> +}
>> +; CHECK-LABEL: @test_01(
>> +; CHECK: store i32 %2, i32* getelementptr inbounds ([100 x i32], [100 x
>> i32]* @A, i32 0, i64 0)
>> +; CHECK: store i32 %13, i32* %11
>> +; CHECK: store i32 10, i32* getelementptr inbounds ([100 x i32], [100 x
>> i32]* @A, i32 0, i64 0)
>> +
>> +
>> +; Postive Test case-
>> +;void foo(int N) {
>> +; A[0] = N;
>> +; for(int i=0;i<N;++i)
>> +; A[i]=i;
>> +; A[0] = 10;
>> +;}
>> +;; Stores should not be optimized away.
>> +define void @test_02(i32 %N) #0 {
>> + %1 = alloca i32
>> + %i = alloca i32
>> + store i32 %N, i32* %1
>> + %2 = load i32, i32* %1
>> + store i32 %2, i32* getelementptr inbounds ([100 x i32], [100 x i32]*
>> @A, i32 0, i64 0)
>> + store i32 0, i32* %i
>> + br label %3
>> +
>> +; <label>:3 ; preds = %12, %0
>> + %4 = load i32, i32* %i
>> + %5 = load i32, i32* %1
>> + %6 = icmp slt i32 %4, %5
>> + br i1 %6, label %7, label %15
>> +
>> +; <label>:7 ; preds = %3
>> + %8 = load i32, i32* %i
>> + %9 = load i32, i32* %i
>> + %10 = sext i32 %9 to i64
>> + %11 = getelementptr inbounds [100 x i32], [100 x i32]* @A, i32 0, i64
>> %10
>> + store i32 %8, i32* %11
>> + br label %12
>> +
>> +; <label>:12 ; preds = %7
>> + %13 = load i32, i32* %i
>> + %14 = add nsw i32 %13, 1
>> + store i32 %14, i32* %i
>> + br label %3
>> +
>> +; <label>:15 ; preds = %3
>> + store i32 10, i32* getelementptr inbounds ([100 x i32], [100 x i32]*
>> @A, i32 0, i64 0)
>> + ret void
>> +}
>> +
>> +; CHECK-LABEL: @test_02(
>> +; CHECK-NOT: store i32 %2, i32* getelementptr inbounds ([100 x i32],
>> [100 x i32]* @A, i32 0, i64 0)
>> +; CHECK: store i32 %7, i32* %10
>> +; CHECK: store i32 10, i32* getelementptr inbounds ([100 x i32], [100 x
>> i32]* @A, i32 0, i64 0)
>> +
>> +
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150816/d2f8094f/attachment.html>
More information about the llvm-commits
mailing list