[llvm] r245195 - Fix PR24469 resulting from r245025 and re-enable dead store elimination across basicblocks.
Eric Christopher via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 18 14:17:34 PDT 2015
Hi Karthik,
We're also seeing this as non-deterministic. The basic idea is that in a 3
stage build you build stage1 with your system compiler, then stage 2 is
built with that and stage 3 with the output of stage 2. The stage 2 and
stage 3 compilers then need to be bit for bit identical to show that
there's no instability going on. Both the bot and we are seeing bootstrap
failures after this revision - would you mind reverting shortly so we can
figure out what's going on? I'll probably revert in an hour or so if you
haven't.
Thanks!
-eric
On Mon, Aug 17, 2015 at 4:02 AM KARTHIK VENKATESH BHAT via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Hi Nakamura,
> Thanks for the link. I'm a bit new to this can you please let me know if
> my understanding of nondeterministic behavior is correct here.
>
> So build seems to be successful. The warning in stage1_build_clang seems
> to be from other files. So I assume we are talking about "compare_23" in
> the link?
> From what I could understand we are building llvm with clang and comparing
> the .o files generated and checking if there is a difference with and
> without the current change list. Is my understanding correct?
> If that is true the current patch can remove few dead stores if any and
> create difference in .o files generated.
>
> Please if you could guide me if my understanding is correct I can
> investigate more to see if there is actually a problem.
> Thanks and Regards
> Karthik Bhat
>
>
> ------- Original Message -------
> Sender : NAKAMURA Takumi<geek4civic at gmail.com>
> Date : Aug 17, 2015 18:53 (GMT+09:00)
> Title : Re: [llvm] r245195 - Fix PR24469 resulting from r245025 and
> re-enable dead store elimination across basicblocks.
>
> Seems it has nondeterministic behavior. See;
> http://bb.pgr.jp/builders/clang-3stage-i686-linux/builds/2960
>
> 2015-08-17 14:51 GMT+09:00 Karthik Bhat via llvm-commits
> :
> > Author: karthik
> > Date: Mon Aug 17 00:51:39 2015
> > New Revision: 245195
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=245195&view=rev
> > Log:
> > Fix PR24469 resulting from r245025 and re-enable dead store elimination
> across basicblocks.
> > PR24469 resulted because DeleteDeadInstruction in
> handleNonLocalStoreDeletion was
> > deleting the next basic block iterator. Fixed the same by resetting the
> basic block iterator
> > post call to DeleteDeadInstruction.
> >
> >
> > 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=245195&r1=245194&r2=245195&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp (original)
> > +++ llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp Mon Aug 17
> 00:51:39 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, 16> Candidates;
> > + SetVector DeadStores;
> > + SmallVector, 32>
> > + BackEdges;
> > + DenseSet> 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 getStores(BasicBlock *BB) {
> > + SmallVector VecStores;
> > + for (auto &BI : *BB) {
> > + if (StoreInst *SI = dyn_cast(&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 VecStores = getStores(&I);
> > + Candidates[DFSIn] = VecStores;
> > + }
> > + }
> >
> > bool runOnFunction(Function &F) override {
> > if (skipOptnoneFunction(F))
> > @@ -64,7 +97,21 @@ namespace {
> > MD = &getAnalysis();
> > DT = &getAnalysis().getDomTree();
> > TLI = &getAnalysis().getTLI();
> > -
> > + PDT = &getAnalysis();
> > + if (PDT->getRootNode()) {
> > + int Count = PDT->getRootNode()->getDFSNumOut();
> > + SmallVector 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 +130,24 @@ namespace {
> > void RemoveAccessedObjects(const MemoryLocation &LoadedLoc,
> > SmallSetVector &DeadStackObjects,
> > const DataLayout &DL);
> > -
> > + void handleNonLocalStoreDeletion(StoreInst *SI,
> BasicBlock::iterator &BBI,
> > + BasicBlock &CurBlock);
> > + bool isSafeCandidateForDeletion(BasicBlock *SrcBlock, BasicBlock
> *SinkBlock,
> > + StoreInst *SI);
> > + void DeleteDeadInstruction(Instruction *I, MemoryDependenceAnalysis
> &MD,
> > + const TargetLibraryInfo &TLI,
> > + SmallSetVector *ValueSet = nullptr);
> > void getAnalysisUsage(AnalysisUsage &AU) const override {
> > AU.setPreservesCFG();
> > AU.addRequired();
> > AU.addRequired();
> > AU.addRequired();
> > + AU.addRequired();
> > AU.addRequired();
> > AU.addPreserved();
> > AU.addPreserved();
> > AU.addPreserved();
> > + AU.addPreserved();
> > }
> > };
> > }
> > @@ -102,6 +157,7 @@ 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 +167,6 @@ 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 *ValueSet = nullptr) {
> > - SmallVector 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(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 +539,15 @@ 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(Inst))
> > + handleNonLocalStoreDeletion(SI, BBI, BB);
> > + continue;
> > + }
> >
> > // Figure out what location is being stored to.
> > MemoryLocation Loc = getLocForWrite(Inst, *AA);
> > @@ -704,6 +721,50 @@ 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 *ValueSet) {
> > + SmallVector 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(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(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 +992,122 @@ 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 WorkList;
> > + SmallPtrSet 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(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(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::iterator &BBI,
> > + BasicBlock &CurBlock) {
> > + 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;
> > + // DeleteDeadInstruction can delete the current instruction in
> loop
> > + // cases, reset BBI.
> > + BBI = SI;
> > + if (BBI != CurBlock.begin())
> > + --BBI;
> > + }
> > + }
> > + }
> > +}
> >
> > 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=245195&view=auto
> >
> ==============================================================================
> > --- llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
> (added)
> > +++ llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse.ll
> Mon Aug 17 00:51:39 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 x = common global i32 0
> > + at y = common global i32 0
> > + at a = external global i32
> > + at b = external global i32
> > +
> > +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
> > +
> > +; :4
> > + store i32 5, i32* @x
> > + br label %5
> > +
> > +; :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
> > +
> > +; :4
> > + store i32 5, i32* @x
> > + br label %7
> > +
> > +; :5
> > + %6 = load i32, i32* @x
> > + store i32 %6, i32* @y
> > + br label %7
> > +
> > +; :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
> > +
> > +; :4 ; preds = %0
> > + %5 = load i32, i32* @x
> > + store i32 %5, i32* @y
> > + br label %6
> > +
> > +; :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
> > +
> > +
> > +
> > +; Check we safely delete store i32 %g.02, i32* @b below.(PR24469)
> > +define void @test_04() {
> > +entry:
> > + br i1 false, label %for.body, label %for.end.9
> > +
> > +for.cond.1.loopexit: ; preds = %for.body
> > + store i32 0, i32* @b
> > + %0 = load i32, i32* @a
> > + br i1 false, label %for.body, label %for.end.9
> > +
> > +for.body: ; preds =
> %for.cond.1.loopexit, %entry
> > + %g.02 = phi i32 [ undef, %entry ], [ %0, %for.cond.1.loopexit ]
> > + store i32 %g.02, i32* @b
> > + br label %for.cond.1.loopexit
> > +
> > +for.end.9: ; preds =
> %for.cond.1.loopexit, %entry
> > + ret void
> > +}
> > +
> > +; CHECK-LABEL: @test_04(
> > +; CHECK-NOT: store i32 %g.02, i32* @b
> > +; CHECK-NOT: %g.02 = phi i32 [ undef, %entry ], [ %0,
> %for.cond.1.loopexit ]
> > +; CHECK-NOT: %0 = load i32, i32* @a
> >
> > 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=245195&view=auto
> >
> ==============================================================================
> > ---
> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll
> (added)
> > +++
> llvm/trunk/test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll Mon
> Aug 17 00:51:39 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> +; 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
> > +
> > +; :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
> > +
> > +; :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
> > +
> > +; :14 ; preds = %7
> > + %15 = load i32, i32* %i
> > + %16 = add nsw i32 %15, 1
> > + store i32 %16, i32* %i
> > + br label %3
> > +
> > +; :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> +; 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
> > +
> > +; :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
> > +
> > +; :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
> > +
> > +; :12 ; preds = %7
> > + %13 = load i32, i32* %i
> > + %14 = add nsw i32 %13, 1
> > + store i32 %14, i32* %i
> > + br label %3
> > +
> > +; :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
> _______________________________________________
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