- if (ExtType == ISD::SEXTLOAD)
- // Having the top bits zero doesn't help when sign extending.
- Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl,
- Result.getValueType(),
- Result, DAG.getValueType(SrcVT));
- else if (ExtType == ISD::ZEXTLOAD || NVT == Result.getValueType())
- // All the top bits are guaranteed to be zero - inform the optimizers.
- Result = DAG.getNode(ISD::AssertZext, dl,
- Result.getValueType(), Result,
- DAG.getValueType(SrcVT));
-
- Tmp1 = LegalizeOp(Result);
- Tmp2 = LegalizeOp(Ch);
- } else if (SrcWidth & (SrcWidth - 1)) {
- // If not loading a power-of-2 number of bits, expand as two loads.
- assert(!SrcVT.isVector() && "Unsupported extload!");
- unsigned RoundWidth = 1 << Log2_32(SrcWidth);
- assert(RoundWidth < SrcWidth);
- unsigned ExtraWidth = SrcWidth - RoundWidth;
- assert(ExtraWidth < RoundWidth);
- assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
- "Load size not an integral number of bytes!");
- EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
- EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
- SDValue Lo, Hi, Ch;
- unsigned IncrementSize;
+ EVT SrcVT = LD->getMemoryVT();
+ unsigned SrcWidth = SrcVT.getSizeInBits();
+ unsigned Alignment = LD->getAlignment();
+ bool isVolatile = LD->isVolatile();
+ bool isNonTemporal = LD->isNonTemporal();
+
+ if (SrcWidth != SrcVT.getStoreSizeInBits() &&
+ // Some targets pretend to have an i1 loading operation, and actually
+ // load an i8. This trick is correct for ZEXTLOAD because the top 7
+ // bits are guaranteed to be zero; it helps the optimizers understand
+ // that these bits are zero. It is also useful for EXTLOAD, since it
+ // tells the optimizers that those bits are undefined. It would be
+ // nice to have an effective generic way of getting these benefits...
+ // Until such a way is found, don't insist on promoting i1 here.
+ (SrcVT != MVT::i1 ||
+ TLI.getLoadExtAction(ExtType, MVT::i1) == TargetLowering::Promote)) {
+ // Promote to a byte-sized load if not loading an integral number of
+ // bytes. For example, promote EXTLOAD:i20 -> EXTLOAD:i24.
+ unsigned NewWidth = SrcVT.getStoreSizeInBits();
+ EVT NVT = EVT::getIntegerVT(*DAG.getContext(), NewWidth);
+ SDValue Ch;
+
+ // The extra bits are guaranteed to be zero, since we stored them that
+ // way. A zext load from NVT thus automatically gives zext from SrcVT.
+
+ ISD::LoadExtType NewExtType =
+ ExtType == ISD::ZEXTLOAD ? ISD::ZEXTLOAD : ISD::EXTLOAD;
+
+ Result = DAG.getExtLoad(NewExtType, dl, Node->getValueType(0),
+ Tmp1, Tmp2, LD->getPointerInfo(),
+ NVT, isVolatile, isNonTemporal, Alignment);
+
+ Ch = Result.getValue(1); // The chain.
+
+ if (ExtType == ISD::SEXTLOAD)
+ // Having the top bits zero doesn't help when sign extending.
+ Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl,
+ Result.getValueType(),
+ Result, DAG.getValueType(SrcVT));
+ else if (ExtType == ISD::ZEXTLOAD || NVT == Result.getValueType())
+ // All the top bits are guaranteed to be zero - inform the optimizers.
+ Result = DAG.getNode(ISD::AssertZext, dl,
+ Result.getValueType(), Result,
+ DAG.getValueType(SrcVT));
+
+ Tmp1 = LegalizeOp(Result);
+ Tmp2 = LegalizeOp(Ch);
+ } else if (SrcWidth & (SrcWidth - 1)) {
+ // If not loading a power-of-2 number of bits, expand as two loads.
+ assert(!SrcVT.isVector() && "Unsupported extload!");
+ unsigned RoundWidth = 1 << Log2_32(SrcWidth);
+ assert(RoundWidth < SrcWidth);
+ unsigned ExtraWidth = SrcWidth - RoundWidth;
+ assert(ExtraWidth < RoundWidth);
+ assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
+ "Load size not an integral number of bytes!");
+ EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
+ EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
+ SDValue Lo, Hi, Ch;
+ unsigned IncrementSize;
+
+ if (TLI.isLittleEndian()) {
+ // EXTLOAD:i24 -> ZEXTLOAD:i16 | (shl EXTLOAD@+2:i8, 16)
+ // Load the bottom RoundWidth bits.
+ Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, Node->getValueType(0),
+ Tmp1, Tmp2,
+ LD->getPointerInfo(), RoundVT, isVolatile,
+ isNonTemporal, Alignment);
+
+ // Load the remaining ExtraWidth bits.
+ IncrementSize = RoundWidth / 8;
+ Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
+ DAG.getIntPtrConstant(IncrementSize));
+ Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getPointerInfo().getWithOffset(IncrementSize),
+ ExtraVT, isVolatile, isNonTemporal,
+ MinAlign(Alignment, IncrementSize));
+
+ // Build a factor node to remember that this load is independent of
+ // the other one.
+ Ch = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
+ Hi.getValue(1));
+
+ // Move the top bits to the right place.
+ Hi = DAG.getNode(ISD::SHL, dl, Hi.getValueType(), Hi,
+ DAG.getConstant(RoundWidth,
+ TLI.getShiftAmountTy(Hi.getValueType())));
+
+ // Join the hi and lo parts.
+ Result = DAG.getNode(ISD::OR, dl, Node->getValueType(0), Lo, Hi);
+ } else {
+ // Big endian - avoid unaligned loads.
+ // EXTLOAD:i24 -> (shl EXTLOAD:i16, 8) | ZEXTLOAD@+2:i8
+ // Load the top RoundWidth bits.
+ Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getPointerInfo(), RoundVT, isVolatile,
+ isNonTemporal, Alignment);
+
+ // Load the remaining ExtraWidth bits.
+ IncrementSize = RoundWidth / 8;
+ Tmp2 = DAG.getNode(ISD::ADD, dl, Tmp2.getValueType(), Tmp2,
+ DAG.getIntPtrConstant(IncrementSize));
+ Lo = DAG.getExtLoad(ISD::ZEXTLOAD,
+ dl, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getPointerInfo().getWithOffset(IncrementSize),
+ ExtraVT, isVolatile, isNonTemporal,
+ MinAlign(Alignment, IncrementSize));
+
+ // Build a factor node to remember that this load is independent of
+ // the other one.
+ Ch = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
+ Hi.getValue(1));
+
+ // Move the top bits to the right place.
+ Hi = DAG.getNode(ISD::SHL, dl, Hi.getValueType(), Hi,
+ DAG.getConstant(ExtraWidth,
+ TLI.getShiftAmountTy(Hi.getValueType())));
+
+ // Join the hi and lo parts.
+ Result = DAG.getNode(ISD::OR, dl, Node->getValueType(0), Lo, Hi);
+ }