[llvm] r245195 - Fix PR24469 resulting from r245025 and re-enable dead store elimination across basicblocks.
NAKAMURA Takumi via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 19 06:14:38 PDT 2015
Clearing DeadStores in runOnFunction() can stabilize the issue.
In FunctionPass, runOnFunction() may be called frequently in its life.
It'd be not a good idea to hold per-function states in a instance of
FunctionPass.
On Wed, Aug 19, 2015 at 1:19 PM NAKAMURA Takumi <geek4civic at gmail.com>
wrote:
> FYI, it's not bootstrapping issue.
> Iterative running (with just-built clang) may reproduce the issue. For me,
> clang/lib/Basic/Targets.cpp is often unstable.
>
> On Wed, Aug 19, 2015 at 12:26 PM KARTHIK VENKATESH BHAT <
> kv.bhat at samsung.com> wrote:
>
>> Thanks Eric for explaining the 3 stage build process. I will try to
>> figure out the reason for this.
>> Thanks & Regards
>> Karthik Bhat
>>
>> ------- Original Message -------
>> Sender : Eric Christopher<echristo at gmail.com>
>> Date : Aug 19, 2015 11:16 (GMT+09:00)
>> Title : Re: Re: [llvm] r245195 - Fix PR24469 resulting from r245025 and
>> re-enable dead store elimination across basicblocks.
>>
>> OK, I've reverted this here:
>>
>>
>> dzur:~/sources/llvm> git svn dcommit
>> Committing to https://llvm.org/svn/llvm-project/llvm/trunk ...
>> D test/Transforms/DeadStoreElimination/cross_block_dse.ll
>> D test/Transforms/DeadStoreElimination/cross_block_dse_loop.ll
>> M lib/Transforms/Scalar/DeadStoreElimination.cpp
>> Committed r245402
>>
>>
>> Thanks.
>>
>>
>> -eric
>>
>>
>> On Tue, Aug 18, 2015 at 2:17 PM Eric Christopher <echristo at gmail.com>
>> wrote:
>>
>> 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
>> _______________________________________________
>> llvm-commits mailing list
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>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
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