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66bb752162
We should query the subtarget of the calling function, not of the intrinsic. This probably makes no functional difference (as libcalls are unlikely to vary across subtargets), but fixes minor compile-time regressions from unnecessary subtarget instantiations. Followup to D157567. Differential Revision: https://reviews.llvm.org/D157848
424 lines
15 KiB
C++
424 lines
15 KiB
C++
//===- PreISelIntrinsicLowering.cpp - Pre-ISel intrinsic lowering pass ----===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass implements IR lowering for the llvm.memcpy, llvm.memmove,
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// llvm.memset, llvm.load.relative and llvm.objc.* intrinsics.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/PreISelIntrinsicLowering.h"
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#include "llvm/Analysis/ObjCARCInstKind.h"
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#include "llvm/Analysis/ObjCARCUtil.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/TargetLowering.h"
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#include "llvm/CodeGen/TargetPassConfig.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/Type.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Transforms/Utils/LowerMemIntrinsics.h"
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using namespace llvm;
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/// Threshold to leave statically sized memory intrinsic calls. Calls of known
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/// size larger than this will be expanded by the pass. Calls of unknown or
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/// lower size will be left for expansion in codegen.
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static cl::opt<int64_t> MemIntrinsicExpandSizeThresholdOpt(
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"mem-intrinsic-expand-size",
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cl::desc("Set minimum mem intrinsic size to expand in IR"), cl::init(-1),
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cl::Hidden);
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namespace {
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struct PreISelIntrinsicLowering {
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const TargetMachine &TM;
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const function_ref<TargetTransformInfo &(Function &)> LookupTTI;
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/// If this is true, assume it's preferably to leave memory intrinsic calls
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/// for replacement with a library call later. Otherwise this depends on
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/// TargetLoweringInfo availability of the corresponding function.
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const bool UseMemIntrinsicLibFunc;
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explicit PreISelIntrinsicLowering(
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const TargetMachine &TM_,
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function_ref<TargetTransformInfo &(Function &)> LookupTTI_,
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bool UseMemIntrinsicLibFunc_ = true)
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: TM(TM_), LookupTTI(LookupTTI_),
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UseMemIntrinsicLibFunc(UseMemIntrinsicLibFunc_) {}
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static bool shouldExpandMemIntrinsicWithSize(Value *Size,
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const TargetTransformInfo &TTI);
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bool expandMemIntrinsicUses(Function &F) const;
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bool lowerIntrinsics(Module &M) const;
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};
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} // namespace
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static bool lowerLoadRelative(Function &F) {
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if (F.use_empty())
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return false;
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bool Changed = false;
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Type *Int32Ty = Type::getInt32Ty(F.getContext());
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Type *Int8Ty = Type::getInt8Ty(F.getContext());
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for (Use &U : llvm::make_early_inc_range(F.uses())) {
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auto CI = dyn_cast<CallInst>(U.getUser());
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if (!CI || CI->getCalledOperand() != &F)
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continue;
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IRBuilder<> B(CI);
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Value *OffsetPtr =
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B.CreateGEP(Int8Ty, CI->getArgOperand(0), CI->getArgOperand(1));
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Value *OffsetI32 = B.CreateAlignedLoad(Int32Ty, OffsetPtr, Align(4));
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Value *ResultPtr = B.CreateGEP(Int8Ty, CI->getArgOperand(0), OffsetI32);
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CI->replaceAllUsesWith(ResultPtr);
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CI->eraseFromParent();
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Changed = true;
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}
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return Changed;
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}
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// ObjCARC has knowledge about whether an obj-c runtime function needs to be
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// always tail-called or never tail-called.
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static CallInst::TailCallKind getOverridingTailCallKind(const Function &F) {
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objcarc::ARCInstKind Kind = objcarc::GetFunctionClass(&F);
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if (objcarc::IsAlwaysTail(Kind))
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return CallInst::TCK_Tail;
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else if (objcarc::IsNeverTail(Kind))
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return CallInst::TCK_NoTail;
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return CallInst::TCK_None;
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}
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static bool lowerObjCCall(Function &F, const char *NewFn,
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bool setNonLazyBind = false) {
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assert(IntrinsicInst::mayLowerToFunctionCall(F.getIntrinsicID()) &&
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"Pre-ISel intrinsics do lower into regular function calls");
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if (F.use_empty())
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return false;
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// If we haven't already looked up this function, check to see if the
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// program already contains a function with this name.
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Module *M = F.getParent();
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FunctionCallee FCache = M->getOrInsertFunction(NewFn, F.getFunctionType());
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if (Function *Fn = dyn_cast<Function>(FCache.getCallee())) {
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Fn->setLinkage(F.getLinkage());
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if (setNonLazyBind && !Fn->isWeakForLinker()) {
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// If we have Native ARC, set nonlazybind attribute for these APIs for
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// performance.
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Fn->addFnAttr(Attribute::NonLazyBind);
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}
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}
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CallInst::TailCallKind OverridingTCK = getOverridingTailCallKind(F);
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for (Use &U : llvm::make_early_inc_range(F.uses())) {
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auto *CB = cast<CallBase>(U.getUser());
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if (CB->getCalledFunction() != &F) {
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objcarc::ARCInstKind Kind = objcarc::getAttachedARCFunctionKind(CB);
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(void)Kind;
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assert((Kind == objcarc::ARCInstKind::RetainRV ||
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Kind == objcarc::ARCInstKind::UnsafeClaimRV) &&
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"use expected to be the argument of operand bundle "
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"\"clang.arc.attachedcall\"");
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U.set(FCache.getCallee());
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continue;
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}
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auto *CI = cast<CallInst>(CB);
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assert(CI->getCalledFunction() && "Cannot lower an indirect call!");
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IRBuilder<> Builder(CI->getParent(), CI->getIterator());
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SmallVector<Value *, 8> Args(CI->args());
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SmallVector<llvm::OperandBundleDef, 1> BundleList;
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CI->getOperandBundlesAsDefs(BundleList);
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CallInst *NewCI = Builder.CreateCall(FCache, Args, BundleList);
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NewCI->setName(CI->getName());
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// Try to set the most appropriate TailCallKind based on both the current
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// attributes and the ones that we could get from ObjCARC's special
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// knowledge of the runtime functions.
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//
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// std::max respects both requirements of notail and tail here:
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// * notail on either the call or from ObjCARC becomes notail
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// * tail on either side is stronger than none, but not notail
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CallInst::TailCallKind TCK = CI->getTailCallKind();
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NewCI->setTailCallKind(std::max(TCK, OverridingTCK));
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// Transfer the 'returned' attribute from the intrinsic to the call site.
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// By applying this only to intrinsic call sites, we avoid applying it to
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// non-ARC explicit calls to things like objc_retain which have not been
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// auto-upgraded to use the intrinsics.
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unsigned Index;
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if (F.getAttributes().hasAttrSomewhere(Attribute::Returned, &Index) &&
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Index)
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NewCI->addParamAttr(Index - AttributeList::FirstArgIndex,
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Attribute::Returned);
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if (!CI->use_empty())
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CI->replaceAllUsesWith(NewCI);
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CI->eraseFromParent();
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}
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return true;
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}
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// TODO: Should refine based on estimated number of accesses (e.g. does it
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// require splitting based on alignment)
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bool PreISelIntrinsicLowering::shouldExpandMemIntrinsicWithSize(
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Value *Size, const TargetTransformInfo &TTI) {
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ConstantInt *CI = dyn_cast<ConstantInt>(Size);
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if (!CI)
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return true;
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uint64_t Threshold = MemIntrinsicExpandSizeThresholdOpt.getNumOccurrences()
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? MemIntrinsicExpandSizeThresholdOpt
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: TTI.getMaxMemIntrinsicInlineSizeThreshold();
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uint64_t SizeVal = CI->getZExtValue();
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// Treat a threshold of 0 as a special case to force expansion of all
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// intrinsics, including size 0.
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return SizeVal > Threshold || Threshold == 0;
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}
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static bool canEmitLibcall(const TargetMachine &TM, Function *F,
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RTLIB::Libcall LC) {
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// TODO: Should this consider the address space of the memcpy?
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const TargetLowering *TLI = TM.getSubtargetImpl(*F)->getTargetLowering();
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return TLI->getLibcallName(LC) != nullptr;
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}
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// TODO: Handle atomic memcpy and memcpy.inline
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// TODO: Pass ScalarEvolution
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bool PreISelIntrinsicLowering::expandMemIntrinsicUses(Function &F) const {
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Intrinsic::ID ID = F.getIntrinsicID();
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bool Changed = false;
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for (User *U : llvm::make_early_inc_range(F.users())) {
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Instruction *Inst = cast<Instruction>(U);
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switch (ID) {
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case Intrinsic::memcpy: {
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auto *Memcpy = cast<MemCpyInst>(Inst);
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Function *ParentFunc = Memcpy->getFunction();
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const TargetTransformInfo &TTI = LookupTTI(*ParentFunc);
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if (shouldExpandMemIntrinsicWithSize(Memcpy->getLength(), TTI)) {
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if (UseMemIntrinsicLibFunc &&
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canEmitLibcall(TM, ParentFunc, RTLIB::MEMCPY))
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break;
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// TODO: For optsize, emit the loop into a separate function
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expandMemCpyAsLoop(Memcpy, TTI);
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Changed = true;
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Memcpy->eraseFromParent();
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}
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break;
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}
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case Intrinsic::memmove: {
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auto *Memmove = cast<MemMoveInst>(Inst);
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Function *ParentFunc = Memmove->getFunction();
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const TargetTransformInfo &TTI = LookupTTI(*ParentFunc);
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if (shouldExpandMemIntrinsicWithSize(Memmove->getLength(), TTI)) {
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if (UseMemIntrinsicLibFunc &&
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canEmitLibcall(TM, ParentFunc, RTLIB::MEMMOVE))
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break;
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if (expandMemMoveAsLoop(Memmove, TTI)) {
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Changed = true;
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Memmove->eraseFromParent();
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}
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}
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break;
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}
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case Intrinsic::memset: {
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auto *Memset = cast<MemSetInst>(Inst);
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Function *ParentFunc = Memset->getFunction();
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const TargetTransformInfo &TTI = LookupTTI(*ParentFunc);
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if (shouldExpandMemIntrinsicWithSize(Memset->getLength(), TTI)) {
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if (UseMemIntrinsicLibFunc &&
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canEmitLibcall(TM, ParentFunc, RTLIB::MEMSET))
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break;
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expandMemSetAsLoop(Memset);
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Changed = true;
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Memset->eraseFromParent();
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}
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break;
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}
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default:
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llvm_unreachable("unhandled intrinsic");
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}
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}
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return Changed;
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}
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bool PreISelIntrinsicLowering::lowerIntrinsics(Module &M) const {
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bool Changed = false;
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for (Function &F : M) {
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switch (F.getIntrinsicID()) {
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default:
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break;
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case Intrinsic::memcpy:
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case Intrinsic::memmove:
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case Intrinsic::memset:
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Changed |= expandMemIntrinsicUses(F);
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break;
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case Intrinsic::load_relative:
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Changed |= lowerLoadRelative(F);
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break;
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case Intrinsic::objc_autorelease:
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Changed |= lowerObjCCall(F, "objc_autorelease");
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break;
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case Intrinsic::objc_autoreleasePoolPop:
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Changed |= lowerObjCCall(F, "objc_autoreleasePoolPop");
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break;
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case Intrinsic::objc_autoreleasePoolPush:
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Changed |= lowerObjCCall(F, "objc_autoreleasePoolPush");
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break;
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case Intrinsic::objc_autoreleaseReturnValue:
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Changed |= lowerObjCCall(F, "objc_autoreleaseReturnValue");
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break;
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case Intrinsic::objc_copyWeak:
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Changed |= lowerObjCCall(F, "objc_copyWeak");
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break;
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case Intrinsic::objc_destroyWeak:
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Changed |= lowerObjCCall(F, "objc_destroyWeak");
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break;
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case Intrinsic::objc_initWeak:
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Changed |= lowerObjCCall(F, "objc_initWeak");
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break;
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case Intrinsic::objc_loadWeak:
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Changed |= lowerObjCCall(F, "objc_loadWeak");
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break;
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case Intrinsic::objc_loadWeakRetained:
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Changed |= lowerObjCCall(F, "objc_loadWeakRetained");
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break;
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case Intrinsic::objc_moveWeak:
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Changed |= lowerObjCCall(F, "objc_moveWeak");
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break;
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case Intrinsic::objc_release:
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Changed |= lowerObjCCall(F, "objc_release", true);
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break;
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case Intrinsic::objc_retain:
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Changed |= lowerObjCCall(F, "objc_retain", true);
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break;
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case Intrinsic::objc_retainAutorelease:
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Changed |= lowerObjCCall(F, "objc_retainAutorelease");
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break;
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case Intrinsic::objc_retainAutoreleaseReturnValue:
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Changed |= lowerObjCCall(F, "objc_retainAutoreleaseReturnValue");
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break;
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case Intrinsic::objc_retainAutoreleasedReturnValue:
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Changed |= lowerObjCCall(F, "objc_retainAutoreleasedReturnValue");
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break;
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case Intrinsic::objc_retainBlock:
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Changed |= lowerObjCCall(F, "objc_retainBlock");
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break;
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case Intrinsic::objc_storeStrong:
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Changed |= lowerObjCCall(F, "objc_storeStrong");
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break;
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case Intrinsic::objc_storeWeak:
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Changed |= lowerObjCCall(F, "objc_storeWeak");
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break;
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case Intrinsic::objc_unsafeClaimAutoreleasedReturnValue:
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Changed |= lowerObjCCall(F, "objc_unsafeClaimAutoreleasedReturnValue");
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break;
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case Intrinsic::objc_retainedObject:
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Changed |= lowerObjCCall(F, "objc_retainedObject");
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break;
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case Intrinsic::objc_unretainedObject:
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Changed |= lowerObjCCall(F, "objc_unretainedObject");
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break;
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case Intrinsic::objc_unretainedPointer:
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Changed |= lowerObjCCall(F, "objc_unretainedPointer");
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break;
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case Intrinsic::objc_retain_autorelease:
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Changed |= lowerObjCCall(F, "objc_retain_autorelease");
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break;
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case Intrinsic::objc_sync_enter:
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Changed |= lowerObjCCall(F, "objc_sync_enter");
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break;
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case Intrinsic::objc_sync_exit:
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Changed |= lowerObjCCall(F, "objc_sync_exit");
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break;
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}
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}
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return Changed;
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}
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namespace {
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class PreISelIntrinsicLoweringLegacyPass : public ModulePass {
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public:
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static char ID;
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PreISelIntrinsicLoweringLegacyPass() : ModulePass(ID) {}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequired<TargetTransformInfoWrapperPass>();
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AU.addRequired<TargetPassConfig>();
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}
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bool runOnModule(Module &M) override {
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auto LookupTTI = [this](Function &F) -> TargetTransformInfo & {
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return this->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
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};
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const auto &TM = getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
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PreISelIntrinsicLowering Lowering(TM, LookupTTI);
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return Lowering.lowerIntrinsics(M);
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}
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};
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} // end anonymous namespace
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char PreISelIntrinsicLoweringLegacyPass::ID;
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INITIALIZE_PASS_BEGIN(PreISelIntrinsicLoweringLegacyPass,
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"pre-isel-intrinsic-lowering",
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"Pre-ISel Intrinsic Lowering", false, false)
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INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
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INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
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INITIALIZE_PASS_END(PreISelIntrinsicLoweringLegacyPass,
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"pre-isel-intrinsic-lowering",
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"Pre-ISel Intrinsic Lowering", false, false)
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ModulePass *llvm::createPreISelIntrinsicLoweringPass() {
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return new PreISelIntrinsicLoweringLegacyPass();
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}
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PreservedAnalyses PreISelIntrinsicLoweringPass::run(Module &M,
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ModuleAnalysisManager &AM) {
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auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
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auto LookupTTI = [&FAM](Function &F) -> TargetTransformInfo & {
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return FAM.getResult<TargetIRAnalysis>(F);
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};
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PreISelIntrinsicLowering Lowering(TM, LookupTTI);
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if (!Lowering.lowerIntrinsics(M))
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return PreservedAnalyses::all();
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else
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return PreservedAnalyses::none();
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}
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