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-rw-r--r--lib/CodeGen/SelectionDAG/LegalizeDAG.cpp240
1 files changed, 176 insertions, 64 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 70dd97d223..54cfad6930 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1820,76 +1820,188 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
return Op.ResNo ? Tmp4 : Tmp3;
} else {
MVT::ValueType SrcVT = LD->getLoadedVT();
- switch (TLI.getLoadXAction(ExtType, SrcVT)) {
- default: assert(0 && "This action is not supported yet!");
- case TargetLowering::Promote:
- assert(SrcVT == MVT::i1 &&
- "Can only promote extending LOAD from i1 -> i8!");
- Result = DAG.getExtLoad(ExtType, Node->getValueType(0), Tmp1, Tmp2,
- LD->getSrcValue(), LD->getSrcValueOffset(),
- MVT::i8, LD->isVolatile(), LD->getAlignment());
- Tmp1 = Result.getValue(0);
- Tmp2 = Result.getValue(1);
- break;
- case TargetLowering::Custom:
- isCustom = true;
- // FALLTHROUGH
- case TargetLowering::Legal:
- Result = DAG.UpdateNodeOperands(Result, Tmp1, Tmp2, LD->getOffset());
- Tmp1 = Result.getValue(0);
- Tmp2 = Result.getValue(1);
-
- if (isCustom) {
- Tmp3 = TLI.LowerOperation(Result, DAG);
- if (Tmp3.Val) {
- Tmp1 = LegalizeOp(Tmp3);
- Tmp2 = LegalizeOp(Tmp3.getValue(1));
- }
+ unsigned SrcWidth = MVT::getSizeInBits(SrcVT);
+ int SVOffset = LD->getSrcValueOffset();
+ unsigned Alignment = LD->getAlignment();
+ bool isVolatile = LD->isVolatile();
+
+ if (SrcWidth != MVT::getStoreSizeInBits(SrcVT) &&
+ // 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.getLoadXAction(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 = MVT::getStoreSizeInBits(SrcVT);
+ MVT::ValueType NVT = MVT::getIntegerType(NewWidth);
+ SDOperand 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, Node->getValueType(0),
+ Tmp1, Tmp2, LD->getSrcValue(), SVOffset,
+ NVT, isVolatile, 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, 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, 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(MVT::isExtendedVT(SrcVT) && !MVT::isVector(SrcVT) &&
+ "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!");
+ MVT::ValueType RoundVT = MVT::getIntegerType(RoundWidth);
+ MVT::ValueType ExtraVT = MVT::getIntegerType(ExtraWidth);
+ SDOperand 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, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getSrcValue(), SVOffset, RoundVT, isVolatile,
+ Alignment);
+
+ // Load the remaining ExtraWidth bits.
+ IncrementSize = RoundWidth / 8;
+ Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2,
+ DAG.getIntPtrConstant(IncrementSize));
+ Hi = DAG.getExtLoad(ExtType, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getSrcValue(), SVOffset + IncrementSize,
+ ExtraVT, isVolatile,
+ MinAlign(Alignment, IncrementSize));
+
+ // Build a factor node to remember that this load is independent of the
+ // other one.
+ Ch = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
+ Hi.getValue(1));
+
+ // Move the top bits to the right place.
+ Hi = DAG.getNode(ISD::SHL, Hi.getValueType(), Hi,
+ DAG.getConstant(RoundWidth, TLI.getShiftAmountTy()));
+
+ // Join the hi and lo parts.
+ Result = DAG.getNode(ISD::OR, Node->getValueType(0), Lo, Hi);
} else {
- // If this is an unaligned load and the target doesn't support it,
- // expand it.
- if (!TLI.allowsUnalignedMemoryAccesses()) {
- unsigned ABIAlignment = TLI.getTargetData()->
- getABITypeAlignment(MVT::getTypeForValueType(LD->getLoadedVT()));
- if (LD->getAlignment() < ABIAlignment){
- Result = ExpandUnalignedLoad(cast<LoadSDNode>(Result.Val), DAG,
- TLI);
- Tmp1 = Result.getOperand(0);
- Tmp2 = Result.getOperand(1);
- Tmp1 = LegalizeOp(Tmp1);
- Tmp2 = LegalizeOp(Tmp2);
+ // Big endian - avoid unaligned loads.
+ // EXTLOAD:i24 -> (shl EXTLOAD:i16, 8) | ZEXTLOAD@+2:i8
+ // Load the top RoundWidth bits.
+ Hi = DAG.getExtLoad(ExtType, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getSrcValue(), SVOffset, RoundVT, isVolatile,
+ Alignment);
+
+ // Load the remaining ExtraWidth bits.
+ IncrementSize = RoundWidth / 8;
+ Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2,
+ DAG.getIntPtrConstant(IncrementSize));
+ Lo = DAG.getExtLoad(ISD::ZEXTLOAD, Node->getValueType(0), Tmp1, Tmp2,
+ LD->getSrcValue(), SVOffset + IncrementSize,
+ ExtraVT, isVolatile,
+ MinAlign(Alignment, IncrementSize));
+
+ // Build a factor node to remember that this load is independent of the
+ // other one.
+ Ch = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
+ Hi.getValue(1));
+
+ // Move the top bits to the right place.
+ Hi = DAG.getNode(ISD::SHL, Hi.getValueType(), Hi,
+ DAG.getConstant(ExtraWidth, TLI.getShiftAmountTy()));
+
+ // Join the hi and lo parts.
+ Result = DAG.getNode(ISD::OR, Node->getValueType(0), Lo, Hi);
+ }
+
+ Tmp1 = LegalizeOp(Result);
+ Tmp2 = LegalizeOp(Ch);
+ } else {
+ switch (TLI.getLoadXAction(ExtType, SrcVT)) {
+ default: assert(0 && "This action is not supported yet!");
+ case TargetLowering::Custom:
+ isCustom = true;
+ // FALLTHROUGH
+ case TargetLowering::Legal:
+ Result = DAG.UpdateNodeOperands(Result, Tmp1, Tmp2, LD->getOffset());
+ Tmp1 = Result.getValue(0);
+ Tmp2 = Result.getValue(1);
+
+ if (isCustom) {
+ Tmp3 = TLI.LowerOperation(Result, DAG);
+ if (Tmp3.Val) {
+ Tmp1 = LegalizeOp(Tmp3);
+ Tmp2 = LegalizeOp(Tmp3.getValue(1));
+ }
+ } else {
+ // If this is an unaligned load and the target doesn't support it,
+ // expand it.
+ if (!TLI.allowsUnalignedMemoryAccesses()) {
+ unsigned ABIAlignment = TLI.getTargetData()->
+ getABITypeAlignment(MVT::getTypeForValueType(LD->getLoadedVT()));
+ if (LD->getAlignment() < ABIAlignment){
+ Result = ExpandUnalignedLoad(cast<LoadSDNode>(Result.Val), DAG,
+ TLI);
+ Tmp1 = Result.getOperand(0);
+ Tmp2 = Result.getOperand(1);
+ Tmp1 = LegalizeOp(Tmp1);
+ Tmp2 = LegalizeOp(Tmp2);
+ }
}
}
- }
- break;
- case TargetLowering::Expand:
- // f64 = EXTLOAD f32 should expand to LOAD, FP_EXTEND
- if (SrcVT == MVT::f32 && Node->getValueType(0) == MVT::f64) {
- SDOperand Load = DAG.getLoad(SrcVT, Tmp1, Tmp2, LD->getSrcValue(),
- LD->getSrcValueOffset(),
- LD->isVolatile(), LD->getAlignment());
- Result = DAG.getNode(ISD::FP_EXTEND, Node->getValueType(0), Load);
- Tmp1 = LegalizeOp(Result); // Relegalize new nodes.
- Tmp2 = LegalizeOp(Load.getValue(1));
+ break;
+ case TargetLowering::Expand:
+ // f64 = EXTLOAD f32 should expand to LOAD, FP_EXTEND
+ if (SrcVT == MVT::f32 && Node->getValueType(0) == MVT::f64) {
+ SDOperand Load = DAG.getLoad(SrcVT, Tmp1, Tmp2, LD->getSrcValue(),
+ LD->getSrcValueOffset(),
+ LD->isVolatile(), LD->getAlignment());
+ Result = DAG.getNode(ISD::FP_EXTEND, Node->getValueType(0), Load);
+ Tmp1 = LegalizeOp(Result); // Relegalize new nodes.
+ Tmp2 = LegalizeOp(Load.getValue(1));
+ break;
+ }
+ assert(ExtType != ISD::EXTLOAD &&"EXTLOAD should always be supported!");
+ // Turn the unsupported load into an EXTLOAD followed by an explicit
+ // zero/sign extend inreg.
+ Result = DAG.getExtLoad(ISD::EXTLOAD, Node->getValueType(0),
+ Tmp1, Tmp2, LD->getSrcValue(),
+ LD->getSrcValueOffset(), SrcVT,
+ LD->isVolatile(), LD->getAlignment());
+ SDOperand ValRes;
+ if (ExtType == ISD::SEXTLOAD)
+ ValRes = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
+ Result, DAG.getValueType(SrcVT));
+ else
+ ValRes = DAG.getZeroExtendInReg(Result, SrcVT);
+ Tmp1 = LegalizeOp(ValRes); // Relegalize new nodes.
+ Tmp2 = LegalizeOp(Result.getValue(1)); // Relegalize new nodes.
break;
}
- assert(ExtType != ISD::EXTLOAD &&"EXTLOAD should always be supported!");
- // Turn the unsupported load into an EXTLOAD followed by an explicit
- // zero/sign extend inreg.
- Result = DAG.getExtLoad(ISD::EXTLOAD, Node->getValueType(0),
- Tmp1, Tmp2, LD->getSrcValue(),
- LD->getSrcValueOffset(), SrcVT,
- LD->isVolatile(), LD->getAlignment());
- SDOperand ValRes;
- if (ExtType == ISD::SEXTLOAD)
- ValRes = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
- Result, DAG.getValueType(SrcVT));
- else
- ValRes = DAG.getZeroExtendInReg(Result, SrcVT);
- Tmp1 = LegalizeOp(ValRes); // Relegalize new nodes.
- Tmp2 = LegalizeOp(Result.getValue(1)); // Relegalize new nodes.
- break;
}
+
// Since loads produce two values, make sure to remember that we legalized
// both of them.
AddLegalizedOperand(SDOperand(Node, 0), Tmp1);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-07-24 22:27:57 +0000