InstCombinePHI.cpp File Reference

#include "InstCombine.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/DataLayout.h"

Include dependency graph for InstCombinePHI.cpp:

Go to the source code of this file.

Classes
struct	llvm::DenseMapInfo< LoweredPHIRecord >

Namespaces
	llvm
	List of target independent CodeGen pass IDs.

Functions
static bool	isSafeAndProfitableToSinkLoad (LoadInst *L)
static bool	DeadPHICycle (PHINode *PN, SmallPtrSet< PHINode *, 16 > &PotentiallyDeadPHIs)
static bool	PHIsEqualValue (PHINode *PN, Value *NonPhiInVal, SmallPtrSet< PHINode *, 16 > &ValueEqualPHIs)

Function Documentation

static bool DeadPHICycle ( PHINode *  PN, SmallPtrSet< PHINode *, 16 > &  PotentiallyDeadPHIs  )

static

DeadPHICycle - Return true if this PHI node is only used by a PHI node cycle that is dead.

Definition at line 508 of file InstCombinePHI.cpp.

References llvm::Value::hasOneUse(), llvm::SmallPtrSet< PtrType, SmallSize >::insert(), llvm::SmallPtrSetImpl::size(), llvm::Instruction::use_back(), and llvm::Value::use_empty().

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

static bool isSafeAndProfitableToSinkLoad ( LoadInst *  L )

static

isSafeAndProfitableToSinkLoad - Return true if we know that it is safe to sink the load out of the block that defines it. This means that it must be obvious the value of the load is not changed from the point of the load to the end of the block it is in.

Finally, it is safe, but not profitable, to sink a load targeting a non-address-taken alloca. Doing so will cause us to not promote the alloca to a register.

Definition at line 247 of file InstCombinePHI.cpp.

References llvm::BasicBlock::end(), llvm::User::getOperand(), llvm::Instruction::getParent(), and llvm::GetElementPtrInst::hasAllConstantIndices().

static bool PHIsEqualValue ( PHINode *  PN, Value *  NonPhiInVal, SmallPtrSet< PHINode *, 16 > &  ValueEqualPHIs  )

static

PHIsEqualValue - Return true if this phi node is always equal to NonPhiInVal. This happens with mutually cyclic phi nodes like: z = some value; x = phi (y, z); y = phi (x, z)

Definition at line 530 of file InstCombinePHI.cpp.

References llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), llvm::SmallPtrSet< PtrType, SmallSize >::insert(), and llvm::SmallPtrSetImpl::size().

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