[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
Evan Cheng
evan.cheng at apple.com
Wed Feb 15 13:59:16 PST 2006
Changes in directory llvm/lib/CodeGen/SelectionDAG:
SelectionDAGISel.cpp updated: 1.160 -> 1.161
---
Log message:
Turn a memcpy from string constant into a series of stores of constant values.
---
Diffs of the changes: (+69 -47)
SelectionDAGISel.cpp | 116 ++++++++++++++++++++++++++++++---------------------
1 files changed, 69 insertions(+), 47 deletions(-)
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.160 llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.161
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.160 Tue Feb 14 19:54:51 2006
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Wed Feb 15 15:59:04 2006
@@ -807,36 +807,15 @@
/// getStringValue - Turn an LLVM constant pointer that eventually points to a
/// global into a string value. Return an empty string if we can't do it.
///
-static std::string getStringValue(Value *V, unsigned Offset = 0) {
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
- if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
- ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
- if (Init->isString()) {
- std::string Result = Init->getAsString();
- if (Offset < Result.size()) {
- // If we are pointing INTO The string, erase the beginning...
- Result.erase(Result.begin(), Result.begin()+Offset);
-
- // Take off the null terminator, and any string fragments after it.
- std::string::size_type NullPos = Result.find_first_of((char)0);
- if (NullPos != std::string::npos)
- Result.erase(Result.begin()+NullPos, Result.end());
- return Result;
- }
- }
- }
- } else if (Constant *C = dyn_cast<Constant>(V)) {
- if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
- return getStringValue(GV, Offset);
- else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
- if (CE->getOpcode() == Instruction::GetElementPtr) {
- // Turn a gep into the specified offset.
- if (CE->getNumOperands() == 3 &&
- cast<Constant>(CE->getOperand(1))->isNullValue() &&
- isa<ConstantInt>(CE->getOperand(2))) {
- return getStringValue(CE->getOperand(0),
- Offset+cast<ConstantInt>(CE->getOperand(2))->getRawValue());
- }
+static std::string getStringValue(GlobalVariable *GV, unsigned Offset = 0) {
+ if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
+ ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
+ if (Init->isString()) {
+ std::string Result = Init->getAsString();
+ if (Offset < Result.size()) {
+ // If we are pointing INTO The string, erase the beginning...
+ Result.erase(Result.begin(), Result.begin()+Offset);
+ return Result;
}
}
}
@@ -1523,13 +1502,10 @@
DAG.setRoot(Result.second);
}
-/// getMemSetValue - Vectorized representation of the memset value
+/// getMemsetValue - Vectorized representation of the memset value
/// operand.
static SDOperand getMemsetValue(SDOperand Value, MVT::ValueType VT,
- SelectionDAG &DAG) {
- if (VT == MVT::i8)
- return Value;
-
+ SelectionDAG &DAG, TargetLowering &TLI) {
MVT::ValueType CurVT = VT;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Value)) {
uint64_t Val = C->getValue() & 255;
@@ -1556,6 +1532,24 @@
}
}
+/// getMemsetStringVal - Similar to getMemsetValue. Except this is only
+/// used when a memcpy is turned into a memset when the source is a constant
+/// string ptr.
+static SDOperand getMemsetStringVal(MVT::ValueType VT,
+ SelectionDAG &DAG, TargetLowering &TLI,
+ std::string &Str, unsigned Offset) {
+ MVT::ValueType CurVT = VT;
+ uint64_t Val = 0;
+ unsigned MSB = getSizeInBits(VT) / 8;
+ if (TLI.isLittleEndian())
+ Offset = Offset + MSB - 1;
+ for (unsigned i = 0; i != MSB; ++i) {
+ Val = (Val << 8) | Str[Offset];
+ Offset += TLI.isLittleEndian() ? -1 : 1;
+ }
+ return DAG.getConstant(Val, VT);
+}
+
/// getMemBasePlusOffset - Returns base and offset node for the
static SDOperand getMemBasePlusOffset(SDOperand Base, unsigned Offset,
SelectionDAG &DAG, TargetLowering &TLI) {
@@ -1640,7 +1634,7 @@
for (unsigned i = 0; i < NumMemOps; i++) {
MVT::ValueType VT = MemOps[i];
unsigned VTSize = getSizeInBits(VT) / 8;
- SDOperand Value = getMemsetValue(Op2, VT, DAG);
+ SDOperand Value = getMemsetValue(Op2, VT, DAG, TLI);
SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, getRoot(),
Value,
getMemBasePlusOffset(Op1, Offset, DAG, TLI),
@@ -1655,21 +1649,49 @@
if (MeetsMaxMemopRequirement(MemOps, TLI.getMaxStoresPerMemcpy(),
Size->getValue(), Align, TLI)) {
unsigned NumMemOps = MemOps.size();
- unsigned Offset = 0;
+ unsigned SrcOff = 0, DstOff = 0;
+ GlobalAddressSDNode *G = NULL;
+ std::string Str;
+
+ if (Op2.getOpcode() == ISD::GlobalAddress)
+ G = cast<GlobalAddressSDNode>(Op2);
+ else if (Op2.getOpcode() == ISD::ADD &&
+ Op2.getOperand(0).getOpcode() == ISD::GlobalAddress &&
+ Op2.getOperand(1).getOpcode() == ISD::Constant) {
+ G = cast<GlobalAddressSDNode>(Op2.getOperand(0));
+ SrcOff += cast<ConstantSDNode>(Op2.getOperand(1))->getValue();
+ }
+ if (G) {
+ GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal());
+ if (GV)
+ Str = getStringValue(GV);
+ }
+
for (unsigned i = 0; i < NumMemOps; i++) {
MVT::ValueType VT = MemOps[i];
unsigned VTSize = getSizeInBits(VT) / 8;
- SDOperand Value =
- DAG.getLoad(VT, getRoot(),
- getMemBasePlusOffset(Op2, Offset, DAG, TLI),
- DAG.getSrcValue(I.getOperand(2), Offset));
- SDOperand Store =
- DAG.getNode(ISD::STORE, MVT::Other, Value.getValue(1),
- Value,
- getMemBasePlusOffset(Op1, Offset, DAG, TLI),
- DAG.getSrcValue(I.getOperand(1), Offset));
+ SDOperand Value, Chain, Store;
+
+ if (!Str.empty()) {
+ Value = getMemsetStringVal(VT, DAG, TLI, Str, SrcOff);
+ Chain = getRoot();
+ Store =
+ DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
+ getMemBasePlusOffset(Op1, DstOff, DAG, TLI),
+ DAG.getSrcValue(I.getOperand(1), DstOff));
+ } else {
+ Value = DAG.getLoad(VT, getRoot(),
+ getMemBasePlusOffset(Op2, SrcOff, DAG, TLI),
+ DAG.getSrcValue(I.getOperand(2), SrcOff));
+ Chain = Value.getValue(1);
+ Store =
+ DAG.getNode(ISD::STORE, MVT::Other, Chain, Value,
+ getMemBasePlusOffset(Op1, DstOff, DAG, TLI),
+ DAG.getSrcValue(I.getOperand(1), DstOff));
+ }
OutChains.push_back(Store);
- Offset += VTSize;
+ SrcOff += VTSize;
+ DstOff += VTSize;
}
}
break;
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