Trivially eliminate TrivialLocalMemoryOpsElimination pass - recommit

Follow up on commit 3ae1be7 by dropping the unused pass - no observable
performance impact has been confirmed.

(cherry picked from commit 6a215e5)

Author: Artem Gindinson

IGC/Compiler/CustomSafeOptPass.cpp

@@ -2451,179 +2451,6 @@ void CustomSafeOptPass::visitExtractElementInst(ExtractElementInst& I)
     dp4WithIdentityMatrix(I);
 }
 
-///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-// This pass removes dead local memory loads and stores. If we remove all such loads and stores, we also
-// remove all local memory fences together with barriers that follow.
-//
-IGC_INITIALIZE_PASS_BEGIN(TrivialLocalMemoryOpsElimination, "TrivialLocalMemoryOpsElimination", "TrivialLocalMemoryOpsElimination", false, false)
-IGC_INITIALIZE_PASS_END(TrivialLocalMemoryOpsElimination, "TrivialLocalMemoryOpsElimination", "TrivialLocalMemoryOpsElimination", false, false)
-
-char TrivialLocalMemoryOpsElimination::ID = 0;
-
-TrivialLocalMemoryOpsElimination::TrivialLocalMemoryOpsElimination() : FunctionPass(ID)
-{
-    initializeTrivialLocalMemoryOpsEliminationPass(*PassRegistry::getPassRegistry());
-}
-
-bool TrivialLocalMemoryOpsElimination::runOnFunction(Function& F)
-{
-    bool change = false;
-
-    IGCMD::MetaDataUtils* pMdUtil = getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils();
-    if (!isEntryFunc(pMdUtil, &F))
-    {
-        // Skip if it is non-entry function.  For example, a subroutine
-        //   foo ( local int* p) { ...... store v, p; ......}
-        // in which no localMemoptimization will be performed.
-        return change;
-    }
-
-    visit(F);
-    if (!abortPass && (m_LocalLoadsToRemove.empty() ^ m_LocalStoresToRemove.empty()))
-    {
-        for (StoreInst* Inst : m_LocalStoresToRemove)
-        {
-            Inst->eraseFromParent();
-            change = true;
-        }
-
-        for (LoadInst* Inst : m_LocalLoadsToRemove)
-        {
-            if (Inst->use_empty())
-            {
-                Inst->eraseFromParent();
-                change = true;
-            }
-        }
-
-        for (CallInst* Inst : m_LocalFencesBariersToRemove)
-        {
-            Inst->eraseFromParent();
-            change = true;
-        }
-    }
-    m_LocalStoresToRemove.clear();
-    m_LocalLoadsToRemove.clear();
-    m_LocalFencesBariersToRemove.clear();
-
-    return change;
-}
-
-/*
-OCL instruction barrier(CLK_LOCAL_MEM_FENCE); is translate to two instructions
-call void @llvm.genx.GenISA.memoryfence(i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 true)
-call void @llvm.genx.GenISA.threadgroupbarrier()
-
-if we remove call void @llvm.genx.GenISA.memoryfence(i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 true)
-we must remove next instruction if it is call void @llvm.genx.GenISA.threadgroupbarrier()
-*/
-void TrivialLocalMemoryOpsElimination::findNextThreadGroupBarrierInst(Instruction& I)
-{
-    auto nextInst = I.getNextNonDebugInstruction();
-    if (isa<GenIntrinsicInst>(nextInst))
-    {
-        GenIntrinsicInst* II = cast<GenIntrinsicInst>(nextInst);
-        if (II->getIntrinsicID() == GenISAIntrinsic::GenISA_threadgroupbarrier)
-        {
-            m_LocalFencesBariersToRemove.push_back(dyn_cast<CallInst>(nextInst));
-        }
-    }
-}
-
-void TrivialLocalMemoryOpsElimination::visitLoadInst(LoadInst& I)
-{
-    if (I.getPointerAddressSpace() == ADDRESS_SPACE_LOCAL)
-    {
-        m_LocalLoadsToRemove.push_back(&I);
-    }
-    else if (I.getPointerAddressSpace() == ADDRESS_SPACE_GENERIC)
-    {
-        abortPass = true;
-    }
-}
-
-void TrivialLocalMemoryOpsElimination::visitStoreInst(StoreInst& I)
-{
-    if (I.getPointerAddressSpace() == ADDRESS_SPACE_LOCAL)
-    {
-        if (auto *GV = dyn_cast<GlobalVariable>(I.getPointerOperand()->stripPointerCasts()))
-        {
-            // Device sanitizer instrumentation pass inserts a new local memory
-            // variable and inserts store to the variable in a kernel. The
-            // variable is loaded later in no-inline functions. For this case,
-            // do not eliminate the store.
-            if (GV->getName().startswith("__Asan"))
-            {
-                return;
-            }
-        }
-        m_LocalStoresToRemove.push_back(&I);
-    }
-    else if (I.getPointerAddressSpace() == ADDRESS_SPACE_GENERIC)
-    {
-        abortPass = true;
-    }
-}
-
-bool TrivialLocalMemoryOpsElimination::isLocalBarrier(CallInst& I)
-{
-    //check arguments in call void @llvm.genx.GenISA.memoryfence(i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 true) if match to
-    // (i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 true) it is local barrier
-    std::vector<bool> argumentsOfMemoryBarrier;
-
-    for (auto arg = I.arg_begin(); arg != I.arg_end(); ++arg)
-    {
-        ConstantInt* ci = dyn_cast<ConstantInt>(arg);
-        if (ci) {
-            argumentsOfMemoryBarrier.push_back(ci->getValue().getBoolValue());
-        }
-        else {
-            // argument is not a constant, so we can't tell.
-            return false;
-        }
-    }
-
-    return argumentsOfMemoryBarrier == m_argumentsOfLocalMemoryBarrier;
-}
-
-// If any call instruction use pointer to local memory abort pass execution
-void TrivialLocalMemoryOpsElimination::anyCallInstUseLocalMemory(CallInst& I)
-{
-    Function* fn = I.getCalledFunction();
-
-    if (fn != NULL)
-    {
-        for (auto arg = fn->arg_begin(); arg != fn->arg_end(); ++arg)
-        {
-            if (arg->getType()->isPointerTy())
-            {
-                if (arg->getType()->getPointerAddressSpace() == ADDRESS_SPACE_LOCAL || arg->getType()->getPointerAddressSpace() == ADDRESS_SPACE_GENERIC) abortPass = true;
-            }
-        }
-    }
-}
-
-void TrivialLocalMemoryOpsElimination::visitCallInst(CallInst& I)
-{
-    // detect only: llvm.genx.GenISA.memoryfence(i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 true)
-    // (note: the first and last arguments are true)
-    // and add them with immediately following barriers to m_LocalFencesBariersToRemove
-    anyCallInstUseLocalMemory(I);
-
-    if (isa<GenIntrinsicInst>(I))
-    {
-        GenIntrinsicInst* II = cast<GenIntrinsicInst>(&I);
-        if (II->getIntrinsicID() == GenISAIntrinsic::GenISA_memoryfence)
-        {
-            if (isLocalBarrier(I))
-            {
-                m_LocalFencesBariersToRemove.push_back(&I);
-                findNextThreadGroupBarrierInst(I);
-            }
-        }
-    }
- }
-
 ////////////////////////////////////////////////////////////////////////////////
 IGC_INITIALIZE_PASS_BEGIN(TrivialUnnecessaryTGMFenceElimination, "TrivialUnnecessaryTGMFenceElimination", "TrivialUnnecessaryTGMFenceElimination", false, false)
 IGC_INITIALIZE_PASS_END(TrivialUnnecessaryTGMFenceElimination, "TrivialUnnecessaryTGMFenceElimination", "TrivialUnnecessaryTGMFenceElimination", false, false)

IGC/Compiler/CustomSafeOptPass.hpp

@@ -108,43 +108,6 @@ namespace IGC
         llvm::Value* analyzeTreeForTrunc64bto32b(const llvm::Use& OperandUse, llvm::SmallVector<llvm::BinaryOperator*, 8>& OpsToDelete);
     };
 
-    // TODO: Remove this pass as unused
-    class TrivialLocalMemoryOpsElimination : public llvm::FunctionPass, public llvm::InstVisitor<TrivialLocalMemoryOpsElimination>
-    {
-    public:
-        static char ID;
-
-        TrivialLocalMemoryOpsElimination();
-
-        virtual void getAnalysisUsage(llvm::AnalysisUsage& AU) const override
-        {
-            AU.addRequired<CodeGenContextWrapper>();
-            AU.addRequired<MetaDataUtilsWrapper>();
-            AU.setPreservesCFG();
-        }
-
-        virtual bool runOnFunction(llvm::Function& F) override;
-
-        virtual llvm::StringRef getPassName() const override
-        {
-            return "TrivialLocalMemoryOpsElimination";
-        }
-
-        void visitLoadInst(llvm::LoadInst& I);
-        void visitStoreInst(llvm::StoreInst& I);
-        void visitCallInst(llvm::CallInst& I);
-        bool isLocalBarrier(llvm::CallInst& I);
-        void findNextThreadGroupBarrierInst(llvm::Instruction& I);
-        void anyCallInstUseLocalMemory(llvm::CallInst& I);
-
-    private:
-        llvm::SmallVector<llvm::LoadInst*, 16> m_LocalLoadsToRemove;
-        llvm::SmallVector<llvm::StoreInst*, 16> m_LocalStoresToRemove;
-        llvm::SmallVector<llvm::CallInst*, 16> m_LocalFencesBariersToRemove;
-
-        bool abortPass = false;
-        const std::vector<bool> m_argumentsOfLocalMemoryBarrier{ true, false, false, false, false, false, true };
-    };
     class TrivialUnnecessaryTGMFenceElimination : public llvm::FunctionPass, public llvm::InstVisitor<TrivialUnnecessaryTGMFenceElimination>
     {
     public:

IGC/Compiler/InitializePasses.h

@@ -232,7 +232,6 @@ void initializeRegisterEstimatorPass(llvm::PassRegistry&);
 void initializeVariableReuseAnalysisPass(llvm::PassRegistry &);
 void initializeResourceLoopAnalysisPass(llvm::PassRegistry &);
 void initializeTranslationTablePass(llvm::PassRegistry&);
-void initializeTrivialLocalMemoryOpsEliminationPass(llvm::PassRegistry&);
 void initializeTrivialUnnecessaryTGMFenceEliminationPass(llvm::PassRegistry&);
 void initializeSLMConstPropPass(llvm::PassRegistry&);
 void initializeBlendToDiscardPass(llvm::PassRegistry&);