Author: laurov
Date: Wed Aug 1 14:34:21 2007
New Revision: 40682
URL: http://llvm.org/viewvc/llvm-project?rev=40682&view=rev
Log:
Expand unaligned loads/stores when the target doesn't support them. (PR1548)
Added:
llvm/trunk/test/CodeGen/ARM/unaligned_load_store.ll
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp?rev=40682&r1=40681&r2=40682&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp Wed Aug 1 14:34:21 2007
@@ -550,6 +550,93 @@
return Result;
}
+/// ExpandUnalignedStore - Expands an unaligned store to 2 half-size stores.
+static
+SDOperand ExpandUnalignedStore(StoreSDNode *ST, SelectionDAG &DAG,
+ TargetLowering &TLI) {
+ assert(MVT::isInteger(ST->getStoredVT()) &&
+ "Non integer unaligned stores not implemented.");
+ int SVOffset = ST->getSrcValueOffset();
+ SDOperand Chain = ST->getChain();
+ SDOperand Ptr = ST->getBasePtr();
+ SDOperand Val = ST->getValue();
+ MVT::ValueType VT = Val.getValueType();
+ // Get the half-size VT
+ MVT::ValueType NewStoredVT = ST->getStoredVT() - 1;
+ int NumBits = MVT::getSizeInBits(NewStoredVT);
+ int Alignment = ST->getAlignment();
+ int IncrementSize = NumBits / 8;
+
+ // Divide the stored value in two parts.
+ SDOperand ShiftAmount = DAG.getConstant(NumBits, TLI.getShiftAmountTy());
+ SDOperand Lo = Val;
+ SDOperand Hi = DAG.getNode(ISD::SRL, VT, Val, ShiftAmount);
+
+ // Store the two parts
+ SDOperand Store1, Store2;
+ Store1 = DAG.getTruncStore(Chain, TLI.isLittleEndian()?Lo:Hi, Ptr,
+ ST->getSrcValue(), SVOffset, NewStoredVT,
+ ST->isVolatile(), Alignment);
+ Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
+ DAG.getConstant(IncrementSize, TLI.getPointerTy()));
+ Store2 = DAG.getTruncStore(Chain, TLI.isLittleEndian()?Hi:Lo, Ptr,
+ ST->getSrcValue(), SVOffset + IncrementSize,
+ NewStoredVT, ST->isVolatile(), Alignment);
+
+ return DAG.getNode(ISD::TokenFactor, MVT::Other, Store1, Store2);
+}
+
+/// ExpandUnalignedLoad - Expands an unaligned load to 2 half-size loads.
+static
+SDOperand ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
+ TargetLowering &TLI) {
+ assert(MVT::isInteger(LD->getLoadedVT()) &&
+ "Non integer unaligned loads not implemented.");
+ int SVOffset = LD->getSrcValueOffset();
+ SDOperand Chain = LD->getChain();
+ SDOperand Ptr = LD->getBasePtr();
+ MVT::ValueType VT = LD->getValueType(0);
+ MVT::ValueType NewLoadedVT = LD->getLoadedVT() - 1;
+ int NumBits = MVT::getSizeInBits(NewLoadedVT);
+ int Alignment = LD->getAlignment();
+ int IncrementSize = NumBits / 8;
+ ISD::LoadExtType HiExtType = LD->getExtensionType();
+
+ // If the original load is NON_EXTLOAD, the hi part load must be ZEXTLOAD.
+ if (HiExtType == ISD::NON_EXTLOAD)
+ HiExtType = ISD::ZEXTLOAD;
+
+ // Load the value in two parts
+ SDOperand Lo, Hi;
+ if (TLI.isLittleEndian()) {
+ Lo = DAG.getExtLoad(ISD::ZEXTLOAD, VT, Chain, Ptr, LD->getSrcValue(),
+ SVOffset, NewLoadedVT, LD->isVolatile(), Alignment);
+ Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
+ DAG.getConstant(IncrementSize, TLI.getPointerTy()));
+ Hi = DAG.getExtLoad(HiExtType, VT, Chain, Ptr, LD->getSrcValue(),
+ SVOffset + IncrementSize, NewLoadedVT,
LD->isVolatile(),
+ Alignment);
+ } else {
+ Hi = DAG.getExtLoad(HiExtType, VT, Chain, Ptr, LD->getSrcValue(), SVOffset,
+ NewLoadedVT,LD->isVolatile(), Alignment);
+ Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
+ DAG.getConstant(IncrementSize, TLI.getPointerTy()));
+ Lo = DAG.getExtLoad(ISD::ZEXTLOAD, VT, Chain, Ptr, LD->getSrcValue(),
+ SVOffset + IncrementSize, NewLoadedVT,
LD->isVolatile(),
+ Alignment);
+ }
+
+ // aggregate the two parts
+ SDOperand ShiftAmount = DAG.getConstant(NumBits, TLI.getShiftAmountTy());
+ SDOperand Result = DAG.getNode(ISD::SHL, VT, Hi, ShiftAmount);
+ Result = DAG.getNode(ISD::OR, VT, Result, Lo);
+
+ SDOperand TF = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
+ Hi.getValue(1));
+
+ SDOperand Ops[] = { Result, TF };
+ return DAG.getNode(ISD::MERGE_VALUES, DAG.getVTList(VT, MVT::Other), Ops, 2);
+}
/// LegalizeOp - We know that the specified value has a legal type, and
/// that its operands are legal. Now ensure that the operation itself
@@ -1507,7 +1594,22 @@
switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
default: assert(0 && "This action is not supported yet!");
- case TargetLowering::Legal: break;
+ case TargetLowering::Legal:
+ // 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);
+ Tmp3 = Result.getOperand(0);
+ Tmp4 = Result.getOperand(1);
+ LegalizeOp(Tmp3);
+ LegalizeOp(Tmp4);
+ }
+ }
+ break;
case TargetLowering::Custom:
Tmp1 = TLI.LowerOperation(Tmp3, DAG);
if (Tmp1.Val) {
@@ -1561,6 +1663,21 @@
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);
+ LegalizeOp(Tmp1);
+ LegalizeOp(Tmp2);
+ }
+ }
}
break;
case TargetLowering::Expand:
@@ -1810,7 +1927,17 @@
MVT::ValueType VT = Tmp3.getValueType();
switch (TLI.getOperationAction(ISD::STORE, VT)) {
default: assert(0 && "This action is not supported yet!");
- case TargetLowering::Legal: break;
+ case TargetLowering::Legal:
+ // If this is an unaligned store and the target doesn't support it,
+ // expand it.
+ if (!TLI.allowsUnalignedMemoryAccesses()) {
+ unsigned ABIAlignment = TLI.getTargetData()->
+ getABITypeAlignment(MVT::getTypeForValueType(ST->getStoredVT()));
+ if (ST->getAlignment() < ABIAlignment)
+ Result = ExpandUnalignedStore(cast<StoreSDNode>(Result.Val), DAG,
+ TLI);
+ }
+ break;
case TargetLowering::Custom:
Tmp1 = TLI.LowerOperation(Result, DAG);
if (Tmp1.Val) Result = Tmp1;
@@ -1923,7 +2050,17 @@
MVT::ValueType StVT = cast<StoreSDNode>(Result.Val)->getStoredVT();
switch (TLI.getStoreXAction(StVT)) {
default: assert(0 && "This action is not supported yet!");
- case TargetLowering::Legal: break;
+ case TargetLowering::Legal:
+ // If this is an unaligned store and the target doesn't support it,
+ // expand it.
+ if (!TLI.allowsUnalignedMemoryAccesses()) {
+ unsigned ABIAlignment = TLI.getTargetData()->
+ getABITypeAlignment(MVT::getTypeForValueType(ST->getStoredVT()));
+ if (ST->getAlignment() < ABIAlignment)
+ Result = ExpandUnalignedStore(cast<StoreSDNode>(Result.Val), DAG,
+ TLI);
+ }
+ break;
case TargetLowering::Custom:
Tmp1 = TLI.LowerOperation(Result, DAG);
if (Tmp1.Val) Result = Tmp1;
Added: llvm/trunk/test/CodeGen/ARM/unaligned_load_store.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/unaligned_load_store.ll?rev=40682&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/unaligned_load_store.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/unaligned_load_store.ll Wed Aug 1 14:34:21 2007
@@ -0,0 +1,16 @@
+; RUN: llvm-as < %s | \
+; RUN: llc -march=arm -o %t -f
+; RUN: grep -c ldrb %t | grep 4
+; RUN: grep -c strb %t | grep 4
+
+
+ %struct.p = type <{ i8, i32 }>
[EMAIL PROTECTED] = global %struct.p <{ i8 1, i32 10 }> ; <%struct.p*>
[#uses=1]
[EMAIL PROTECTED] = weak global %struct.p zeroinitializer ;
<%struct.p*> [#uses=1]
+
+define i32 @main() {
+entry:
+ %tmp3 = load i32* getelementptr (%struct.p* @t, i32 0, i32 1), align 1
; <i32> [#uses=2]
+ store i32 %tmp3, i32* getelementptr (%struct.p* @u, i32 0, i32 1),
align 1
+ ret i32 %tmp3
+}
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