mirror of
https://github.com/c64scene-ar/llvm-6502.git
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f042660197
into Analysis as a standalone function, since there's no need for it to be in VMCore. Also, update it to use isKnownNonZero and other goodies available in Analysis, making it more precise, enabling more aggressive optimization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146610 91177308-0d34-0410-b5e6-96231b3b80d8
313 lines
12 KiB
C++
313 lines
12 KiB
C++
//===-- Analysis.cpp - CodeGen LLVM IR Analysis Utilities -----------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines several CodeGen-specific LLVM IR analysis utilties.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/Analysis.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/SelectionDAG.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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/// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
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/// of insertvalue or extractvalue indices that identify a member, return
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/// the linearized index of the start of the member.
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///
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unsigned llvm::ComputeLinearIndex(Type *Ty,
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const unsigned *Indices,
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const unsigned *IndicesEnd,
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unsigned CurIndex) {
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// Base case: We're done.
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if (Indices && Indices == IndicesEnd)
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return CurIndex;
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// Given a struct type, recursively traverse the elements.
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if (StructType *STy = dyn_cast<StructType>(Ty)) {
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for (StructType::element_iterator EB = STy->element_begin(),
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EI = EB,
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EE = STy->element_end();
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EI != EE; ++EI) {
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if (Indices && *Indices == unsigned(EI - EB))
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return ComputeLinearIndex(*EI, Indices+1, IndicesEnd, CurIndex);
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CurIndex = ComputeLinearIndex(*EI, 0, 0, CurIndex);
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}
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return CurIndex;
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}
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// Given an array type, recursively traverse the elements.
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else if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
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Type *EltTy = ATy->getElementType();
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for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i) {
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if (Indices && *Indices == i)
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return ComputeLinearIndex(EltTy, Indices+1, IndicesEnd, CurIndex);
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CurIndex = ComputeLinearIndex(EltTy, 0, 0, CurIndex);
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}
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return CurIndex;
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}
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// We haven't found the type we're looking for, so keep searching.
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return CurIndex + 1;
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}
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/// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
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/// EVTs that represent all the individual underlying
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/// non-aggregate types that comprise it.
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///
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/// If Offsets is non-null, it points to a vector to be filled in
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/// with the in-memory offsets of each of the individual values.
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///
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void llvm::ComputeValueVTs(const TargetLowering &TLI, Type *Ty,
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SmallVectorImpl<EVT> &ValueVTs,
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SmallVectorImpl<uint64_t> *Offsets,
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uint64_t StartingOffset) {
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// Given a struct type, recursively traverse the elements.
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if (StructType *STy = dyn_cast<StructType>(Ty)) {
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const StructLayout *SL = TLI.getTargetData()->getStructLayout(STy);
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for (StructType::element_iterator EB = STy->element_begin(),
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EI = EB,
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EE = STy->element_end();
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EI != EE; ++EI)
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ComputeValueVTs(TLI, *EI, ValueVTs, Offsets,
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StartingOffset + SL->getElementOffset(EI - EB));
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return;
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}
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// Given an array type, recursively traverse the elements.
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if (ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
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Type *EltTy = ATy->getElementType();
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uint64_t EltSize = TLI.getTargetData()->getTypeAllocSize(EltTy);
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for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
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ComputeValueVTs(TLI, EltTy, ValueVTs, Offsets,
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StartingOffset + i * EltSize);
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return;
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}
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// Interpret void as zero return values.
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if (Ty->isVoidTy())
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return;
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// Base case: we can get an EVT for this LLVM IR type.
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ValueVTs.push_back(TLI.getValueType(Ty));
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if (Offsets)
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Offsets->push_back(StartingOffset);
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}
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/// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V.
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GlobalVariable *llvm::ExtractTypeInfo(Value *V) {
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V = V->stripPointerCasts();
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GlobalVariable *GV = dyn_cast<GlobalVariable>(V);
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if (GV && GV->getName() == "llvm.eh.catch.all.value") {
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assert(GV->hasInitializer() &&
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"The EH catch-all value must have an initializer");
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Value *Init = GV->getInitializer();
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GV = dyn_cast<GlobalVariable>(Init);
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if (!GV) V = cast<ConstantPointerNull>(Init);
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}
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assert((GV || isa<ConstantPointerNull>(V)) &&
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"TypeInfo must be a global variable or NULL");
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return GV;
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}
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/// hasInlineAsmMemConstraint - Return true if the inline asm instruction being
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/// processed uses a memory 'm' constraint.
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bool
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llvm::hasInlineAsmMemConstraint(InlineAsm::ConstraintInfoVector &CInfos,
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const TargetLowering &TLI) {
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for (unsigned i = 0, e = CInfos.size(); i != e; ++i) {
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InlineAsm::ConstraintInfo &CI = CInfos[i];
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for (unsigned j = 0, ee = CI.Codes.size(); j != ee; ++j) {
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TargetLowering::ConstraintType CType = TLI.getConstraintType(CI.Codes[j]);
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if (CType == TargetLowering::C_Memory)
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return true;
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}
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// Indirect operand accesses access memory.
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if (CI.isIndirect)
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return true;
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}
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return false;
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}
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/// getFCmpCondCode - Return the ISD condition code corresponding to
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/// the given LLVM IR floating-point condition code. This includes
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/// consideration of global floating-point math flags.
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///
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ISD::CondCode llvm::getFCmpCondCode(FCmpInst::Predicate Pred) {
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switch (Pred) {
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case FCmpInst::FCMP_FALSE: return ISD::SETFALSE;
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case FCmpInst::FCMP_OEQ: return ISD::SETOEQ;
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case FCmpInst::FCMP_OGT: return ISD::SETOGT;
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case FCmpInst::FCMP_OGE: return ISD::SETOGE;
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case FCmpInst::FCMP_OLT: return ISD::SETOLT;
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case FCmpInst::FCMP_OLE: return ISD::SETOLE;
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case FCmpInst::FCMP_ONE: return ISD::SETONE;
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case FCmpInst::FCMP_ORD: return ISD::SETO;
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case FCmpInst::FCMP_UNO: return ISD::SETUO;
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case FCmpInst::FCMP_UEQ: return ISD::SETUEQ;
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case FCmpInst::FCMP_UGT: return ISD::SETUGT;
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case FCmpInst::FCMP_UGE: return ISD::SETUGE;
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case FCmpInst::FCMP_ULT: return ISD::SETULT;
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case FCmpInst::FCMP_ULE: return ISD::SETULE;
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case FCmpInst::FCMP_UNE: return ISD::SETUNE;
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case FCmpInst::FCMP_TRUE: return ISD::SETTRUE;
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default: break;
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}
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llvm_unreachable("Invalid FCmp predicate opcode!");
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return ISD::SETFALSE;
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}
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ISD::CondCode llvm::getFCmpCodeWithoutNaN(ISD::CondCode CC) {
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switch (CC) {
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case ISD::SETOEQ: case ISD::SETUEQ: return ISD::SETEQ;
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case ISD::SETONE: case ISD::SETUNE: return ISD::SETNE;
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case ISD::SETOLT: case ISD::SETULT: return ISD::SETLT;
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case ISD::SETOLE: case ISD::SETULE: return ISD::SETLE;
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case ISD::SETOGT: case ISD::SETUGT: return ISD::SETGT;
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case ISD::SETOGE: case ISD::SETUGE: return ISD::SETGE;
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default: break;
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}
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return CC;
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}
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/// getICmpCondCode - Return the ISD condition code corresponding to
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/// the given LLVM IR integer condition code.
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///
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ISD::CondCode llvm::getICmpCondCode(ICmpInst::Predicate Pred) {
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switch (Pred) {
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case ICmpInst::ICMP_EQ: return ISD::SETEQ;
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case ICmpInst::ICMP_NE: return ISD::SETNE;
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case ICmpInst::ICMP_SLE: return ISD::SETLE;
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case ICmpInst::ICMP_ULE: return ISD::SETULE;
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case ICmpInst::ICMP_SGE: return ISD::SETGE;
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case ICmpInst::ICMP_UGE: return ISD::SETUGE;
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case ICmpInst::ICMP_SLT: return ISD::SETLT;
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case ICmpInst::ICMP_ULT: return ISD::SETULT;
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case ICmpInst::ICMP_SGT: return ISD::SETGT;
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case ICmpInst::ICMP_UGT: return ISD::SETUGT;
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default:
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llvm_unreachable("Invalid ICmp predicate opcode!");
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return ISD::SETNE;
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}
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}
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/// Test if the given instruction is in a position to be optimized
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/// with a tail-call. This roughly means that it's in a block with
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/// a return and there's nothing that needs to be scheduled
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/// between it and the return.
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///
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/// This function only tests target-independent requirements.
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bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attributes CalleeRetAttr,
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const TargetLowering &TLI) {
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const Instruction *I = CS.getInstruction();
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const BasicBlock *ExitBB = I->getParent();
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const TerminatorInst *Term = ExitBB->getTerminator();
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const ReturnInst *Ret = dyn_cast<ReturnInst>(Term);
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// The block must end in a return statement or unreachable.
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//
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// FIXME: Decline tailcall if it's not guaranteed and if the block ends in
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// an unreachable, for now. The way tailcall optimization is currently
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// implemented means it will add an epilogue followed by a jump. That is
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// not profitable. Also, if the callee is a special function (e.g.
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// longjmp on x86), it can end up causing miscompilation that has not
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// been fully understood.
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if (!Ret &&
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(!TLI.getTargetMachine().Options.GuaranteedTailCallOpt ||
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!isa<UnreachableInst>(Term))) return false;
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// If I will have a chain, make sure no other instruction that will have a
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// chain interposes between I and the return.
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if (I->mayHaveSideEffects() || I->mayReadFromMemory() ||
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!isSafeToSpeculativelyExecute(I))
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for (BasicBlock::const_iterator BBI = prior(prior(ExitBB->end())); ;
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--BBI) {
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if (&*BBI == I)
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break;
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// Debug info intrinsics do not get in the way of tail call optimization.
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if (isa<DbgInfoIntrinsic>(BBI))
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continue;
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if (BBI->mayHaveSideEffects() || BBI->mayReadFromMemory() ||
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!isSafeToSpeculativelyExecute(BBI))
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return false;
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}
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// If the block ends with a void return or unreachable, it doesn't matter
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// what the call's return type is.
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if (!Ret || Ret->getNumOperands() == 0) return true;
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// If the return value is undef, it doesn't matter what the call's
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// return type is.
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if (isa<UndefValue>(Ret->getOperand(0))) return true;
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// Conservatively require the attributes of the call to match those of
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// the return. Ignore noalias because it doesn't affect the call sequence.
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const Function *F = ExitBB->getParent();
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unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
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if ((CalleeRetAttr ^ CallerRetAttr) & ~Attribute::NoAlias)
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return false;
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// It's not safe to eliminate the sign / zero extension of the return value.
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if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt))
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return false;
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// Otherwise, make sure the unmodified return value of I is the return value.
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for (const Instruction *U = dyn_cast<Instruction>(Ret->getOperand(0)); ;
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U = dyn_cast<Instruction>(U->getOperand(0))) {
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if (!U)
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return false;
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if (!U->hasOneUse())
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return false;
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if (U == I)
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break;
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// Check for a truly no-op truncate.
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if (isa<TruncInst>(U) &&
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TLI.isTruncateFree(U->getOperand(0)->getType(), U->getType()))
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continue;
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// Check for a truly no-op bitcast.
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if (isa<BitCastInst>(U) &&
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(U->getOperand(0)->getType() == U->getType() ||
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(U->getOperand(0)->getType()->isPointerTy() &&
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U->getType()->isPointerTy())))
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continue;
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// Otherwise it's not a true no-op.
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return false;
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}
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return true;
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}
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bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
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const TargetLowering &TLI) {
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const Function *F = DAG.getMachineFunction().getFunction();
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// Conservatively require the attributes of the call to match those of
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// the return. Ignore noalias because it doesn't affect the call sequence.
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unsigned CallerRetAttr = F->getAttributes().getRetAttributes();
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if (CallerRetAttr & ~Attribute::NoAlias)
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return false;
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// It's not safe to eliminate the sign / zero extension of the return value.
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if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt))
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return false;
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// Check if the only use is a function return node.
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return TLI.isUsedByReturnOnly(Node);
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}
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