#include "InstCombine.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Analysis/Loads.h"
-#include "llvm/Support/PatternMatch.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
-using namespace PatternMatch;
STATISTIC(NumDeadStore, "Number of dead stores eliminated");
Value *Idx[2];
Idx[0] = NullIdx;
Idx[1] = NullIdx;
- Value *V = GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
- New->getName()+".sub", It);
+ Instruction *GEP =
+ GetElementPtrInst::CreateInBounds(New, Idx, Idx + 2,
+ New->getName()+".sub");
+ InsertNewInstBefore(GEP, *It);
// Now make everything use the getelementptr instead of the original
// allocation.
- return ReplaceInstUsesWith(AI, V);
+ return ReplaceInstUsesWith(AI, GEP);
} else if (isa<UndefValue>(AI.getArraySize())) {
return ReplaceInstUsesWith(AI, Constant::getNullValue(AI.getType()));
}
// Attempt to improve the alignment.
if (TD) {
unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()));
+ getOrEnforceKnownAlignment(Op, TD->getPrefTypeAlignment(LI.getType()),TD);
unsigned LoadAlign = LI.getAlignment();
unsigned EffectiveLoadAlign = LoadAlign != 0 ? LoadAlign :
TD->getABITypeAlignment(LI.getType());
if (LI.isVolatile()) return 0;
// Do really simple store-to-load forwarding and load CSE, to catch cases
- // where there are several consequtive memory accesses to the same location,
+ // where there are several consecutive memory accesses to the same location,
// separated by a few arithmetic operations.
BasicBlock::iterator BBI = &LI;
if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
NewCast = IC.Builder->CreateCast(opcode, SIOp0, CastDstTy,
SIOp0->getName()+".c");
- return new StoreInst(NewCast, CastOp);
+ SI.setOperand(0, NewCast);
+ SI.setOperand(1, CastOp);
+ return &SI;
}
/// equivalentAddressValues - Test if A and B will obviously have the same
return false;
}
-// If this instruction has two uses, one of which is a llvm.dbg.declare,
-// return the llvm.dbg.declare.
-DbgDeclareInst *InstCombiner::hasOneUsePlusDeclare(Value *V) {
- if (!V->hasNUses(2))
- return 0;
- for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
- UI != E; ++UI) {
- User *U = *UI;
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(U))
- return DI;
- if (isa<BitCastInst>(U) && U->hasOneUse()) {
- if (DbgDeclareInst *DI = dyn_cast<DbgDeclareInst>(*U->use_begin()))
- return DI;
- }
- }
- return 0;
-}
-
Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
Value *Val = SI.getOperand(0);
Value *Ptr = SI.getOperand(1);
// If the RHS is an alloca with a single use, zapify the store, making the
// alloca dead.
- // If the RHS is an alloca with a two uses, the other one being a
- // llvm.dbg.declare, zapify the store and the declare, making the
- // alloca dead. We must do this to prevent declares from affecting
- // codegen.
if (!SI.isVolatile()) {
if (Ptr->hasOneUse()) {
if (isa<AllocaInst>(Ptr))
if (isa<AllocaInst>(GEP->getOperand(0))) {
if (GEP->getOperand(0)->hasOneUse())
return EraseInstFromFunction(SI);
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(GEP->getOperand(0))) {
- EraseInstFromFunction(*DI);
- return EraseInstFromFunction(SI);
- }
}
}
}
- if (DbgDeclareInst *DI = hasOneUsePlusDeclare(Ptr)) {
- EraseInstFromFunction(*DI);
- return EraseInstFromFunction(SI);
- }
}
// Attempt to improve the alignment.
if (TD) {
unsigned KnownAlign =
- GetOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()));
+ getOrEnforceKnownAlignment(Ptr, TD->getPrefTypeAlignment(Val->getType()),
+ TD);
unsigned StoreAlign = SI.getAlignment();
unsigned EffectiveStoreAlign = StoreAlign != 0 ? StoreAlign :
TD->getABITypeAlignment(Val->getType());
if (SI.isVolatile()) return 0; // Don't hack volatile stores.
- // Attempt to narrow sequences where we load a wide value, perform bitmasks
- // that only affect the low bits of it, and then store it back. This
- // typically arises from bitfield initializers in C++.
- ConstantInt *CI1 =0, *CI2 = 0;
- Value *Ld = 0;
- if (getTargetData() &&
- match(SI.getValueOperand(),
- m_And(m_Or(m_Value(Ld), m_ConstantInt(CI1)), m_ConstantInt(CI2))) &&
- isa<LoadInst>(Ld) &&
- equivalentAddressValues(cast<LoadInst>(Ld)->getPointerOperand(), Ptr)) {
- APInt OrMask = CI1->getValue();
- APInt AndMask = CI2->getValue();
-
- // Compute the prefix of the value that is unmodified by the bitmasking.
- unsigned LeadingAndOnes = AndMask.countLeadingOnes();
- unsigned LeadingOrZeros = OrMask.countLeadingZeros();
- unsigned Prefix = std::min(LeadingAndOnes, LeadingOrZeros);
- uint64_t NewWidth = AndMask.getBitWidth() - Prefix;
- while (NewWidth < AndMask.getBitWidth() &&
- getTargetData()->isIllegalInteger(NewWidth))
- NewWidth = NextPowerOf2(NewWidth);
-
- // If we can find a power-of-2 prefix (and if the values we're working with
- // are themselves POT widths), then we can narrow the store. We rely on
- // later iterations of instcombine to propagate the demanded bits to narrow
- // the other computations in the chain.
- if (NewWidth < AndMask.getBitWidth() &&
- getTargetData()->isLegalInteger(NewWidth)) {
- const Type *NewType = IntegerType::get(Ptr->getContext(), NewWidth);
- const Type *NewPtrType = PointerType::getUnqual(NewType);
-
- Value *NewVal = Builder->CreateTrunc(SI.getValueOperand(), NewType);
- Value *NewPtr = Builder->CreateBitCast(Ptr, NewPtrType);
-
- // On big endian targets, we need to offset from the original pointer
- // in order to store to the low-bit suffix.
- if (getTargetData()->isBigEndian()) {
- uint64_t GEPOffset = (AndMask.getBitWidth() - NewWidth) / 8;
- NewPtr = Builder->CreateConstGEP1_64(NewPtr, GEPOffset);
- }
-
- return new StoreInst(NewVal, NewPtr);
- }
- }
-
// store X, null -> turns into 'unreachable' in SimplifyCFG
if (isa<ConstantPointerNull>(Ptr) && SI.getPointerAddressSpace() == 0) {
if (!isa<UndefValue>(Val)) {
// Insert a PHI node now if we need it.
Value *MergedVal = OtherStore->getOperand(0);
if (MergedVal != SI.getOperand(0)) {
- PHINode *PN = PHINode::Create(MergedVal->getType(), "storemerge");
- PN->reserveOperandSpace(2);
+ PHINode *PN = PHINode::Create(MergedVal->getType(), 2, "storemerge");
PN->addIncoming(SI.getOperand(0), SI.getParent());
PN->addIncoming(OtherStore->getOperand(0), OtherBB);
MergedVal = InsertNewInstBefore(PN, DestBB->front());
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