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Refactor some code
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21772 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -63,6 +63,7 @@ namespace {
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unsigned getRank(Value *V);
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void RewriteExprTree(BinaryOperator *I, unsigned Idx,
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std::vector<ValueEntry> &Ops);
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void OptimizeExpression(unsigned Opcode, std::vector<ValueEntry> &Ops);
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void LinearizeExprTree(BinaryOperator *I, std::vector<ValueEntry> &Ops);
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void LinearizeExpr(BinaryOperator *I);
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void ReassociateBB(BasicBlock *BB);
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@ -343,6 +344,57 @@ static Instruction *ConvertShiftToMul(Instruction *Shl) {
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return Mul;
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}
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void Reassociate::OptimizeExpression(unsigned Opcode,
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std::vector<ValueEntry> &Ops) {
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// Now that we have the linearized expression tree, try to optimize it.
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// Start by folding any constants that we found.
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FoldConstants:
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if (Ops.size() == 1) return;
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if (Constant *V1 = dyn_cast<Constant>(Ops[Ops.size()-2].Op))
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if (Constant *V2 = dyn_cast<Constant>(Ops.back().Op)) {
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Ops.pop_back();
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Ops.back().Op = ConstantExpr::get(Opcode, V1, V2);
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goto FoldConstants;
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}
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// Check for destructive annihilation due to a constant being used.
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if (ConstantIntegral *CstVal = dyn_cast<ConstantIntegral>(Ops.back().Op))
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switch (Opcode) {
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default: break;
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case Instruction::And:
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if (CstVal->isNullValue()) { // ... & 0 -> 0
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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} else if (CstVal->isAllOnesValue()) { // ... & -1 -> ...
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Ops.pop_back();
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}
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break;
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case Instruction::Mul:
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if (CstVal->isNullValue()) { // ... * 0 -> 0
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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} else if (cast<ConstantInt>(CstVal)->getRawValue() == 1) {
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Ops.pop_back(); // ... * 1 -> ...
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}
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break;
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case Instruction::Or:
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if (CstVal->isAllOnesValue()) { // ... | -1 -> -1
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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}
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// FALLTHROUGH!
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case Instruction::Add:
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case Instruction::Xor:
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if (CstVal->isNullValue()) // ... [|^+] 0 -> ...
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Ops.pop_back();
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break;
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}
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// Handle destructive annihilation do to identities between elements in the
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// argument list here.
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}
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/// ReassociateBB - Inspect all of the instructions in this basic block,
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/// reassociating them as we go.
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@ -383,51 +435,9 @@ void Reassociate::ReassociateBB(BasicBlock *BB) {
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// the vector.
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std::stable_sort(Ops.begin(), Ops.end());
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// Now that we have the linearized expression tree, try to optimize it.
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// Start by folding any constants that we found.
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FoldConstants:
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if (Ops.size() > 1)
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if (Constant *V1 = dyn_cast<Constant>(Ops[Ops.size()-2].Op))
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if (Constant *V2 = dyn_cast<Constant>(Ops.back().Op)) {
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Ops.pop_back();
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Ops.back().Op = ConstantExpr::get(I->getOpcode(), V1, V2);
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goto FoldConstants;
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}
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// Check for destructive annihilation due to a constant being used.
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if (Ops.size() != 1) { // Nothing to annihilate?
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if (ConstantIntegral *CstVal = dyn_cast<ConstantIntegral>(Ops.back().Op))
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switch (I->getOpcode()) {
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default: break;
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case Instruction::And:
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if (CstVal->isNullValue()) { // ... & 0 -> 0
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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} else if (CstVal->isAllOnesValue()) { // ... & -1 -> ...
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Ops.pop_back();
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}
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break;
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case Instruction::Mul:
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if (CstVal->isNullValue()) { // ... * 0 -> 0
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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} else if (cast<ConstantInt>(CstVal)->getRawValue() == 1) {
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Ops.pop_back(); // ... * 1 -> ...
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}
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break;
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case Instruction::Or:
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if (CstVal->isAllOnesValue()) { // ... | -1 -> -1
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Ops[0].Op = CstVal;
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Ops.erase(Ops.begin()+1, Ops.end());
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}
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// FALLTHROUGH!
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case Instruction::Add:
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case Instruction::Xor:
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if (CstVal->isNullValue()) // ... [|^+] 0 -> ...
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Ops.pop_back();
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break;
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}
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}
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// OptimizeExpression - Now that we have the expression tree in a convenient
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// sorted form, optimize it globally if possible.
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OptimizeExpression(I->getOpcode(), Ops);
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if (Ops.size() == 1) {
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// This expression tree simplified to something that isn't a tree,
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