static Value *splitStore(StoreInst *Inst, ConversionState &State) {
if (Inst->isVolatile() || Inst->isAtomic())
report_fatal_error("Can't split volatile/atomic stores");
if (cast<IntegerType>(Inst->getValueOperand()->getType())->getBitWidth() % 8
!= 0)
report_fatal_error("Stores must be a multiple of 8 bits");
Value *OrigPtr = State.getConverted(Inst->getPointerOperand());
// OrigPtr is now a placeholder in recursive calls, and so has no name.
if (OrigPtr->getName().empty())
OrigPtr->setName(Inst->getPointerOperand()->getName());
Value *OrigVal = State.getConverted(Inst->getValueOperand());
unsigned Width = cast<IntegerType>(
Inst->getValueOperand()->getType())->getBitWidth();
unsigned LoWidth = Width;
while (!isLegalSize(LoWidth)) LoWidth -= 8;
IntegerType *LoType = IntegerType::get(Inst->getContext(), LoWidth);
IntegerType *HiType = IntegerType::get(Inst->getContext(), Width - LoWidth);
IRBuilder<> IRB(Inst->getParent(), Inst);
Value *BCLo = IRB.CreateBitCast(
OrigPtr,
LoType->getPointerTo(),
OrigPtr->getName() + ".loty");
Value *LoTrunc = IRB.CreateTrunc(
OrigVal, LoType, OrigVal->getName() + ".lo");
IRB.CreateAlignedStore(LoTrunc, BCLo, Inst->getAlignment());
Value *HiLShr = IRB.CreateLShr(
OrigVal, LoWidth, OrigVal->getName() + ".hi.sh");
Value *GEPHi = IRB.CreateConstGEP1_32(BCLo, 1, OrigPtr->getName() + ".hi");
Value *HiTrunc = IRB.CreateTrunc(
HiLShr, HiType, OrigVal->getName() + ".hi");
Value *BCHi = IRB.CreateBitCast(
GEPHi,
HiType->getPointerTo(),
OrigPtr->getName() + ".hity");
Value *StoreHi = IRB.CreateStore(HiTrunc, BCHi);
if (!isLegalSize(Width - LoWidth)) {
// HiTrunc is still illegal, and is redundant with the truncate in the
// recursive call, so just get rid of it.
State.recordConverted(cast<Instruction>(HiTrunc), HiLShr,
/*TakeName=*/false);
StoreHi = splitStore(cast<StoreInst>(StoreHi), State);
// BCHi was still illegal, and has been replaced with a placeholder in the
// recursive call. Since it is redundant with BCLo in the recursive call,
// just splice it out entirely.
State.recordConverted(cast<Instruction>(BCHi), GEPHi, /*TakeName=*/false);
}
State.recordConverted(Inst, StoreHi, /*TakeName=*/false);
return StoreHi;
}
// Split an illegal load into multiple legal loads and return the resulting
// promoted value. The size of the load is assumed to be a multiple of 8.
static Value *splitLoad(LoadInst *Inst, ConversionState &State) {
if (Inst->isVolatile() || Inst->isAtomic())
report_fatal_error("Can't split volatile/atomic loads");
if (cast<IntegerType>(Inst->getType())->getBitWidth() % 8 != 0)
report_fatal_error("Loads must be a multiple of 8 bits");
Value *OrigPtr = State.getConverted(Inst->getPointerOperand());
// OrigPtr is a placeholder in recursive calls, and so has no name
if (OrigPtr->getName().empty())
OrigPtr->setName(Inst->getPointerOperand()->getName());
unsigned Width = cast<IntegerType>(Inst->getType())->getBitWidth();
Type *NewType = getPromotedType(Inst->getType());
unsigned LoWidth = Width;
while (!isLegalSize(LoWidth)) LoWidth -= 8;
IntegerType *LoType = IntegerType::get(Inst->getContext(), LoWidth);
IntegerType *HiType = IntegerType::get(Inst->getContext(), Width - LoWidth);
IRBuilder<> IRB(Inst->getParent(), Inst);
Value *BCLo = IRB.CreateBitCast(
OrigPtr,
LoType->getPointerTo(),
OrigPtr->getName() + ".loty");
Value *LoadLo = IRB.CreateAlignedLoad(
BCLo, Inst->getAlignment(), Inst->getName() + ".lo");
Value *LoExt = IRB.CreateZExt(LoadLo, NewType, LoadLo->getName() + ".ext");
Value *GEPHi = IRB.CreateConstGEP1_32(BCLo, 1, OrigPtr->getName() + ".hi");
Value *BCHi = IRB.CreateBitCast(
GEPHi,
HiType->getPointerTo(),
OrigPtr->getName() + ".hity");
Value *LoadHi = IRB.CreateLoad(BCHi, Inst->getName() + ".hi");
if (!isLegalSize(Width - LoWidth)) {
LoadHi = splitLoad(cast<LoadInst>(LoadHi), State);
// BCHi was still illegal, and has been replaced with a placeholder in the
// recursive call. Since it is redundant with BCLo in the recursive call,
// just splice it out entirely.
State.recordConverted(cast<Instruction>(BCHi), GEPHi, /*TakeName=*/false);
}
Value *HiExt = IRB.CreateZExt(LoadHi, NewType, LoadHi->getName() + ".ext");
Value *HiShift = IRB.CreateShl(HiExt, LoWidth, HiExt->getName() + ".sh");
Value *Result = IRB.CreateOr(LoExt, HiShift);
State.recordConverted(Inst, Result);
return Result;
}