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Combiner alias analysis passes Multisource (release-asserts.)
llvm-svn: 30818
This commit is contained in:
Jim Laskey
parent
3cd1d08ac6
commit
9260b2f86e
@ -46,90 +46,13 @@ namespace {
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static Statistic<> NodesCombined ("dagcombiner",
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"Number of dag nodes combined");
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static cl::opt<bool>
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CombinerAA("combiner-alias-analysis", cl::Hidden,
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cl::desc("Turn on alias analysis turning testing"));
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static cl::opt<bool>
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CombinerAA("combiner-alias-analysis", cl::Hidden,
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cl::desc("Turn on alias analysis turning testing"));
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/// FindBaseOffset - Return true if base is known not to alias with anything
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/// but itself. Provides base object and offset as results.
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bool FindBaseOffset(SDOperand Ptr, SDOperand &Object, int64_t &Offset) {
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// If it's an adding or subtracting a simple constant then add the constant
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// to the offset.
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if (Ptr.getOpcode() == ISD::ADD) {
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if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Ptr.getOperand(1))) {
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bool IsNonAliasing = FindBaseOffset(Ptr.getOperand(0), Object, Offset);
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Offset += C->getValue();
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return IsNonAliasing;
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}
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} else if (Ptr.getOpcode() == ISD::SUB) {
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// FIXME - Aren't all subtract constants converted to add negative constant.
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if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Ptr.getOperand(1))) {
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bool IsNonAliasing = FindBaseOffset(Ptr.getOperand(0), Object, Offset);
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Offset -= C->getValue();
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return IsNonAliasing;
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}
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}
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// Primitive operation.
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Object = Ptr; Offset = 0;
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// If it's any of the following then it can't alias with anything but itself.
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return isa<FrameIndexSDNode>(Ptr) ||
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isa<ConstantPoolSDNode>(Ptr) ||
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isa<GlobalAddressSDNode>(Ptr);
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}
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/// isAlias - Return true if there is any possibility that the two addresses
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/// overlap.
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bool isAlias(SDOperand Ptr1, int64_t Size1, SDOperand SrcValue1,
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SDOperand Ptr2, int64_t Size2, SDOperand SrcValue2) {
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// If they are the same then they must be aliases.
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if (Ptr1 == Ptr2) return true;
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// Gather base node and offset information.
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SDOperand Object1, Object2;
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int64_t Offset1, Offset2;
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bool IsNonAliasing1 = FindBaseOffset(Ptr1, Object1, Offset1);
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bool IsNonAliasing2 = FindBaseOffset(Ptr2, Object2, Offset2);
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// If they have a same base address then...
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if (Object1 == Object2) {
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// Check to see if the addresses overlap.
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return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
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}
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// Otherwise they alias if they are both non aliasing.
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return !IsNonAliasing1 && IsNonAliasing2;
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}
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/// FindAliasInfo - Extracts the relevant alias information from the memory
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/// node. Returns true if the operand was a load.
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bool FindAliasInfo(SDNode *N,
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SDOperand &Ptr, int64_t &Size, SDOperand &SrcValue) {
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switch (N->getOpcode()) {
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case ISD::LOAD:
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Ptr = N->getOperand(1);
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Size = MVT::getSizeInBits(N->getValueType(0)) >> 3;
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SrcValue = N->getOperand(2);
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return true;
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case ISD::STORE:
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Ptr = N->getOperand(2);
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Size = MVT::getSizeInBits(N->getOperand(1).getValueType()) >> 3;
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SrcValue = N->getOperand(3);
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return false;
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default:
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assert(0 && "FindAliasInfo expected a memory operand");
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return false;
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}
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return false;
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}
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//------------------------------ DAGCombiner ---------------------------------//
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class VISIBILITY_HIDDEN DAGCombiner {
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class VISIBILITY_HIDDEN DAGCombiner {
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SelectionDAG &DAG;
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TargetLowering &TLI;
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bool AfterLegalize;
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@ -603,7 +526,7 @@ SDOperand DAGCombiner::visitTokenFactor(SDNode *N) {
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// Start out with this token factor.
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TFs.push_back(N);
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// Iterate through token factors. The TFs grows a new token factors are
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// Iterate through token factors. The TFs grows when new token factors are
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// encountered.
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for (unsigned i = 0; i < TFs.size(); ++i) {
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SDNode *TF = TFs[i];
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@ -3316,12 +3239,6 @@ bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS,
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// If this is a select from two identical things, try to pull the operation
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// through the select.
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if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){
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#if 0
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std::cerr << "SELECT: ["; LHS.Val->dump();
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std::cerr << "] ["; RHS.Val->dump();
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std::cerr << "]\n";
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#endif
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// If this is a load and the token chain is identical, replace the select
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// of two loads with a load through a select of the address to load from.
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// This triggers in things like "select bool X, 10.0, 123.0" after the FP
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@ -3978,6 +3895,72 @@ SDOperand DAGCombiner::BuildUDIV(SDNode *N) {
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return S;
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}
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/// FindBaseOffset - Return true if base is known not to alias with anything
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/// but itself. Provides base object and offset as results.
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static bool FindBaseOffset(SDOperand Ptr, SDOperand &Base, int64_t &Offset) {
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// Assume it is a primitive operation.
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Base = Ptr; Offset = 0;
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// If it's an adding a simple constant then integrate the offset.
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if (Base.getOpcode() == ISD::ADD) {
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if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) {
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Base = Base.getOperand(0);
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Offset += C->getValue();
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}
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}
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// If it's any of the following then it can't alias with anything but itself.
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return isa<FrameIndexSDNode>(Base) ||
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isa<ConstantPoolSDNode>(Base) ||
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isa<GlobalAddressSDNode>(Base);
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}
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/// isAlias - Return true if there is any possibility that the two addresses
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/// overlap.
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static bool isAlias(SDOperand Ptr1, int64_t Size1, SDOperand SrcValue1,
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SDOperand Ptr2, int64_t Size2, SDOperand SrcValue2) {
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// If they are the same then they must be aliases.
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if (Ptr1 == Ptr2) return true;
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// Gather base node and offset information.
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SDOperand Base1, Base2;
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int64_t Offset1, Offset2;
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bool KnownBase1 = FindBaseOffset(Ptr1, Base1, Offset1);
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bool KnownBase2 = FindBaseOffset(Ptr2, Base2, Offset2);
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// If they have a same base address then...
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if (Base1 == Base2) {
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// Check to see if the addresses overlap.
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return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
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}
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// Otherwise they alias if either is unknown.
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return !KnownBase1 || !KnownBase2;
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}
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/// FindAliasInfo - Extracts the relevant alias information from the memory
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/// node. Returns true if the operand was a load.
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static bool FindAliasInfo(SDNode *N,
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SDOperand &Ptr, int64_t &Size, SDOperand &SrcValue) {
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switch (N->getOpcode()) {
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case ISD::LOAD:
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Ptr = N->getOperand(1);
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Size = MVT::getSizeInBits(N->getValueType(0)) >> 3;
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SrcValue = N->getOperand(2);
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return true;
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case ISD::STORE:
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Ptr = N->getOperand(2);
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Size = MVT::getSizeInBits(N->getOperand(1).getValueType()) >> 3;
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SrcValue = N->getOperand(3);
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break;
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default:
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assert(0 && "FindAliasInfo expected a memory operand");
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break;
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}
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return false;
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}
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/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
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/// looking for aliasing nodes and adding them to the Aliases vector.
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void DAGCombiner::GatherAllAliases(SDNode *N, SDOperand OriginalChain,
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