Changes in directory llvm/lib/CodeGen/SelectionDAG:
DAGCombiner.cpp updated: 1.229 -> 1.230
---
Log message:
Use global info for alias analysis.
---
Diffs of the changes: (+38 -9)
DAGCombiner.cpp | 47 ++++++++++++++++++++++++++++++++++++++---------
1 files changed, 38 insertions(+), 9 deletions(-)
Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.229
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.230
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.229 Tue Oct 17 16:24:15 2006
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Wed Oct 18 07:29:57 2006
@@ -256,10 +256,18 @@
void GatherAllAliases(SDNode *N, SDOperand OriginalChain,
SmallVector<SDOperand, 8> &Aliases);
+ /// isAlias - Return true if there is any possibility that the two
addresses
+ /// overlap.
+ bool isAlias(SDOperand Ptr1, int64_t Size1,
+ const Value *SrcValue1, int SrcValueOffset1,
+ SDOperand Ptr2, int64_t Size2,
+ const Value *SrcValue2, int SrcValueOffset1);
+
/// FindAliasInfo - Extracts the relevant alias information from the memory
/// node. Returns true if the operand was a load.
bool FindAliasInfo(SDNode *N,
- SDOperand &Ptr, int64_t &Size, const Value *&SrcValue);
+ SDOperand &Ptr, int64_t &Size,
+ const Value *&SrcValue, int &SrcValueOffset);
/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
/// looking for a better chain (aliasing node.)
@@ -4005,8 +4013,11 @@
/// isAlias - Return true if there is any possibility that the two addresses
/// overlap.
-static bool isAlias(SDOperand Ptr1, int64_t Size1, const Value *SrcValue1,
- SDOperand Ptr2, int64_t Size2, const Value *SrcValue2) {
+bool DAGCombiner::isAlias(SDOperand Ptr1, int64_t Size1,
+ const Value *SrcValue1, int SrcValueOffset1,
+ SDOperand Ptr2, int64_t Size2,
+ const Value *SrcValue2, int SrcValueOffset2)
+{
// If they are the same then they must be aliases.
if (Ptr1 == Ptr2) return true;
@@ -4022,23 +4033,37 @@
return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
}
- // Otherwise they alias if either is unknown.
- return !KnownBase1 || !KnownBase2;
+ // If we know both bases then they can't alias.
+ if (KnownBase1 && KnownBase2) return false;
+
+ // Use alias analysis information.
+ int Overlap1 = Size1 + SrcValueOffset1 + Offset1;
+ int Overlap2 = Size2 + SrcValueOffset2 + Offset2;
+ AliasAnalysis::AliasResult AAResult =
+ AA.alias(SrcValue1, Overlap1, SrcValue2,
Overlap2);
+ if (AAResult == AliasAnalysis::NoAlias)
+ return false;
+
+ // Otherwise we have to assume they alias.
+ return true;
}
/// FindAliasInfo - Extracts the relevant alias information from the memory
/// node. Returns true if the operand was a load.
bool DAGCombiner::FindAliasInfo(SDNode *N,
- SDOperand &Ptr, int64_t &Size, const Value *&SrcValue)
{
+ SDOperand &Ptr, int64_t &Size,
+ const Value *&SrcValue, int &SrcValueOffset) {
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
Ptr = LD->getBasePtr();
Size = MVT::getSizeInBits(LD->getLoadedVT()) >> 3;
SrcValue = LD->getSrcValue();
+ SrcValueOffset = LD->getSrcValueOffset();
return true;
} else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
Ptr = ST->getBasePtr();
Size = MVT::getSizeInBits(ST->getStoredVT()) >> 3;
SrcValue = ST->getSrcValue();
+ SrcValueOffset = ST->getSrcValueOffset();
} else {
assert(0 && "FindAliasInfo expected a memory operand");
}
@@ -4057,7 +4082,8 @@
SDOperand Ptr;
int64_t Size;
const Value *SrcValue;
- bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue);
+ int SrcValueOffset;
+ bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset);
// Starting off.
Chains.push_back(OriginalChain);
@@ -4084,11 +4110,14 @@
SDOperand OpPtr;
int64_t OpSize;
const Value *OpSrcValue;
- bool IsOpLoad = FindAliasInfo(Chain.Val, OpPtr, OpSize, OpSrcValue);
+ int OpSrcValueOffset;
+ bool IsOpLoad = FindAliasInfo(Chain.Val, OpPtr, OpSize,
+ OpSrcValue, OpSrcValueOffset);
// If chain is alias then stop here.
if (!(IsLoad && IsOpLoad) &&
- isAlias(Ptr, Size, SrcValue, OpPtr, OpSize, OpSrcValue)) {
+ isAlias(Ptr, Size, SrcValue, SrcValueOffset,
+ OpPtr, OpSize, OpSrcValue, OpSrcValueOffset)) {
Aliases.push_back(Chain);
} else {
// Look further up the chain.
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