#include "InstCombine.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/PatternMatch.h"

Include dependency graph for InstCombineSelect.cpp:

Defines
#define	DEBUG_TYPE "instcombine"
Functions
static SelectPatternFlavor	MatchSelectPattern (Value V, Value &LHS, Value *&RHS)
static unsigned	GetSelectFoldableOperands (Instruction *I)
static Constant *	GetSelectFoldableConstant (Instruction *I)
static bool	isSelect01 (Constant C1, Constant C2)
static Value *	SimplifyWithOpReplaced (Value V, Value Op, Value RepOp, const DataLayout TD, const TargetLibraryInfo TLI, DominatorTree DT, AssumptionTracker *AT)
static Value *	foldSelectICmpAndOr (SelectInst &SI, Value TrueVal, Value FalseVal, InstCombiner::BuilderTy *Builder)
static bool	CanSelectOperandBeMappingIntoPredBlock (const Value *V, const SelectInst &SI)
static Value *	foldSelectICmpAnd (const SelectInst &SI, ConstantInt TrueVal, ConstantInt FalseVal, InstCombiner::BuilderTy *Builder)

Define Documentation

#define DEBUG_TYPE "instcombine"

Definition at line 21 of file InstCombineSelect.cpp.

Function Documentation

static bool CanSelectOperandBeMappingIntoPredBlock	(	const Value *	V,
		const SelectInst &	SI
	)		`[static]`

CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a PHI node (but the two may be in different blocks). See if the true/false values (V) are live in all of the predecessor blocks of the PHI. For example, cases like this cannot be mapped:

X = phi [ C1, BB1], [C2, BB2] Y = add Z = select X, Y, 0

because Y is not live in BB1/BB2.

Definition at line 665 of file InstCombineSelect.cpp.

References llvm::dyn_cast(), llvm::SelectInst::getCondition(), llvm::Instruction::getParent(), and I.

Referenced by llvm::InstCombiner::visitSelectInst().

static Value* foldSelectICmpAnd	(	const SelectInst &	SI,
		ConstantInt *	TrueVal,
		ConstantInt *	FalseVal,
		InstCombiner::BuilderTy *	Builder
	)		`[static]`

foldSelectICmpAnd - If one of the constants is zero (we know they can't both be) and we have an icmp instruction with zero, and we have an 'and' with the non-constant value and a power of two we can turn the select into a shift on the result of the 'and'.

Definition at line 762 of file InstCombineSelect.cpp.

References llvm::IRBuilder< preserveNames, T, Inserter >::CreateAdd(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateLShr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateShl(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateXor(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateZExtOrTrunc(), llvm::dyn_cast(), llvm::ConstantInt::get(), llvm::ConstantInt::getBitWidth(), llvm::SelectInst::getCondition(), llvm::IRBuilderBase::getContext(), llvm::User::getOperand(), llvm::CmpInst::getPredicate(), llvm::Value::getType(), llvm::ConstantInt::getValue(), llvm::CmpInst::ICMP_NE, llvm::ICmpInst::isEquality(), llvm::Type::isIntegerTy(), llvm::APInt::isPowerOf2(), llvm::ConstantInt::isZero(), llvm::APInt::logBase2(), llvm::PatternMatch::m_And(), llvm::PatternMatch::m_ConstantInt(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_Zero(), and llvm::PatternMatch::match().

Referenced by llvm::InstCombiner::visitSelectInst().

static Value* foldSelectICmpAndOr	(	SelectInst &	SI,
		Value *	TrueVal,
		Value *	FalseVal,
		InstCombiner::BuilderTy *	Builder
	)		`[static]`

foldSelectICmpAndOr - We want to turn: (select (icmp eq (and X, C1), 0), Y, (or Y, C2)) into: (or (shl (and X, C1), C3), y) iff: C1 and C2 are both powers of 2 where: C3 = Log(C2) - Log(C1)

This transform handles cases where: 1. The icmp predicate is inverted 2. The select operands are reversed 3. The magnitude of C2 and C1 are flipped

This also tries to turn --- Single bit tests: if ((x & C) == 0) x |= C to x |= C if ((x & C) != 0) x ^= C to x &= ~C if ((x & C) == 0) x ^= C to x |= C if ((x & C) != 0) x &= ~C to x &= ~C if ((x & C) == 0) x &= ~C to nothing

Definition at line 400 of file InstCombineSelect.cpp.

References llvm::IRBuilder< preserveNames, T, Inserter >::CreateAnd(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateLShr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateOr(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateShl(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateXor(), llvm::IRBuilder< preserveNames, T, Inserter >::CreateZExtOrTrunc(), llvm::dyn_cast(), llvm::SelectInst::getCondition(), llvm::User::getOperand(), llvm::CmpInst::getPredicate(), llvm::Value::getType(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::ICmpInst::isEquality(), llvm::Type::isIntegerTy(), llvm::APInt::logBase2(), llvm::PatternMatch::m_And(), llvm::PatternMatch::m_APInt(), llvm::PatternMatch::m_Or(), llvm::PatternMatch::m_Power2(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::m_Xor(), llvm::PatternMatch::m_Zero(), llvm::PatternMatch::match(), llvm::X, and Y.

Referenced by llvm::InstCombiner::visitSelectInstWithICmp().

static Constant* GetSelectFoldableConstant ( Instruction * I ) [static]

GetSelectFoldableConstant - For the same transformation as the previous function, return the identity constant that goes into the select.

Definition at line 128 of file InstCombineSelect.cpp.

References llvm::APIntOps::And(), llvm::ConstantInt::get(), llvm::Constant::getAllOnesValue(), llvm::Constant::getNullValue(), llvm::Instruction::getOpcode(), llvm::Value::getType(), llvm_unreachable, llvm::LShr, llvm::APIntOps::Or(), and llvm::APIntOps::Xor().

Referenced by llvm::InstCombiner::FoldSelectIntoOp().

static unsigned GetSelectFoldableOperands ( Instruction * I ) [static]

GetSelectFoldableOperands - We want to turn code that looks like this: C = or A, B D = select cond, C, A into: C = select cond, B, 0 D = or A, C

Assuming that the specified instruction is an operand to the select, return a bitmask indicating which operands of this instruction are foldable if they equal the other incoming value of the select.

Definition at line 108 of file InstCombineSelect.cpp.

References llvm::APIntOps::And(), llvm::Instruction::getOpcode(), llvm::LShr, llvm::APIntOps::Or(), and llvm::APIntOps::Xor().

Referenced by llvm::InstCombiner::FoldSelectIntoOp().

static bool isSelect01	(	Constant *	C1,
		Constant *	C2
	)		`[static]`

Definition at line 220 of file InstCombineSelect.cpp.

References llvm::dyn_cast(), llvm::Constant::isAllOnesValue(), llvm::ConstantInt::isOne(), and llvm::ConstantInt::isZero().

Referenced by llvm::InstCombiner::FoldSelectIntoOp().

static SelectPatternFlavor MatchSelectPattern	(	Value *	V,
		Value *&	LHS,
		Value *&	RHS
	)		`[static]`

MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms, returning the kind and providing the out parameter results if we successfully match.

Definition at line 27 of file InstCombineSelect.cpp.

References llvm::dyn_cast(), llvm::SelectInst::getCondition(), llvm::SelectInst::getFalseValue(), llvm::User::getOperand(), llvm::CmpInst::getPredicate(), llvm::SelectInst::getTrueValue(), llvm::CmpInst::ICMP_SGE, llvm::CmpInst::ICMP_SGT, llvm::CmpInst::ICMP_SLE, llvm::CmpInst::ICMP_SLT, llvm::CmpInst::ICMP_UGE, llvm::CmpInst::ICMP_UGT, llvm::CmpInst::ICMP_ULE, llvm::CmpInst::ICMP_ULT, llvm::PatternMatch::m_Neg(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::match(), llvm::SPF_ABS, llvm::SPF_NABS, llvm::SPF_SMAX, llvm::SPF_SMIN, llvm::SPF_UMAX, llvm::SPF_UMIN, and llvm::SPF_UNKNOWN.

Referenced by llvm::InstCombiner::visitSelectInst().

static Value* SimplifyWithOpReplaced	(	Value *	V,
		Value *	Op,
		Value *	RepOp,
		const DataLayout *	TD,
		const TargetLibraryInfo *	TLI,
		DominatorTree *	DT,
		AssumptionTracker *	AT
	)		`[static]`

SimplifyWithOpReplaced - See if V simplifies when its operand Op is replaced with RepOp.

Definition at line 314 of file InstCombineSelect.cpp.

References llvm::CallingConv::C, llvm::ConstantFoldCompareInstOperands(), llvm::ConstantFoldInstOperands(), llvm::ConstantFoldLoadFromConstPtr(), llvm::dyn_cast(), llvm::User::getNumOperands(), llvm::Instruction::getOpcode(), llvm::User::getOperand(), llvm::Value::getType(), I, LI, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SimplifyBinOp(), llvm::SimplifyCmpInst(), and llvm::SmallVectorTemplateCommon< T >::size().

Referenced by llvm::InstCombiner::visitSelectInstWithICmp().

Defines

Functions

Define Documentation

Function Documentation