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CSE simple binary expressions when they are inserted. This makes LSR produce
less huge code that needs to be cleaned up by sdisel. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35959 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -89,7 +89,10 @@ namespace llvm {
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/// we can to share the casts.
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static Value *InsertCastOfTo(Instruction::CastOps opcode, Value *V,
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const Type *Ty);
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/// InsertBinop - Insert the specified binary operator, doing a small amount
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/// of work to avoid inserting an obviously redundant operation.
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static Value *InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
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Value *RHS, Instruction *InsertPt);
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protected:
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Value *expand(SCEV *S) {
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// Check to see if we already expanded this.
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@ -141,8 +144,8 @@ namespace llvm {
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// Emit a bunch of add instructions
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for (int i = S->getNumOperands()-2; i >= 0; --i)
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V = BinaryOperator::createAdd(V, expandInTy(S->getOperand(i), Ty),
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"tmp.", InsertPt);
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V = InsertBinop(Instruction::Add, V, expandInTy(S->getOperand(i), Ty),
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InsertPt);
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return V;
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}
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@ -152,7 +155,7 @@ namespace llvm {
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const Type *Ty = S->getType();
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Value *LHS = expandInTy(S->getLHS(), Ty);
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Value *RHS = expandInTy(S->getRHS(), Ty);
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return BinaryOperator::createSDiv(LHS, RHS, "tmp.", InsertPt);
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return InsertBinop(Instruction::SDiv, LHS, RHS, InsertPt);
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}
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Value *visitAddRecExpr(SCEVAddRecExpr *S);
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@ -68,6 +68,25 @@ Value *SCEVExpander::InsertCastOfTo(Instruction::CastOps opcode, Value *V,
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return CastInst::create(opcode, V, Ty, V->getName(), IP);
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}
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/// InsertBinop - Insert the specified binary operator, doing a small amount
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/// of work to avoid inserting an obviously redundant operation.
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Value *SCEVExpander::InsertBinop(Instruction::BinaryOps Opcode, Value *LHS,
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Value *RHS, Instruction *InsertPt) {
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// Do a quick scan to see if we have this binop nearby. If so, reuse it.
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unsigned ScanLimit = 6;
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for (BasicBlock::iterator IP = InsertPt, E = InsertPt->getParent()->begin();
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ScanLimit; --IP, --ScanLimit) {
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if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(IP))
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if (BinOp->getOpcode() == Opcode && BinOp->getOperand(0) == LHS &&
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BinOp->getOperand(1) == RHS)
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return BinOp;
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if (IP == E) break;
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}
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// If we don't have
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return BinaryOperator::create(Opcode, LHS, RHS, "tmp.", InsertPt);
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}
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Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
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const Type *Ty = S->getType();
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int FirstOp = 0; // Set if we should emit a subtract.
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@ -80,11 +99,12 @@ Value *SCEVExpander::visitMulExpr(SCEVMulExpr *S) {
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// Emit a bunch of multiply instructions
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for (; i >= FirstOp; --i)
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V = BinaryOperator::createMul(V, expandInTy(S->getOperand(i), Ty),
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"tmp.", InsertPt);
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V = InsertBinop(Instruction::Mul, V, expandInTy(S->getOperand(i), Ty),
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InsertPt);
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// -1 * ... ---> 0 - ...
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if (FirstOp == 1)
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V = BinaryOperator::createNeg(V, "tmp.", InsertPt);
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V = InsertBinop(Instruction::Sub, Constant::getNullValue(V->getType()), V,
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InsertPt);
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return V;
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}
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@ -103,7 +123,7 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
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Value *Rest = expandInTy(SCEVAddRecExpr::get(NewOps, L), Ty);
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// FIXME: look for an existing add to use.
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return BinaryOperator::createAdd(Rest, Start, "tmp.", InsertPt);
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return InsertBinop(Instruction::Add, Rest, Start, InsertPt);
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}
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// {0,+,1} --> Insert a canonical induction variable into the loop!
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@ -164,7 +184,7 @@ Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
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}
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}
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return BinaryOperator::createMul(I, F, "tmp.", MulInsertPt);
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return InsertBinop(Instruction::Mul, I, F, MulInsertPt);
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}
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// If this is a chain of recurrences, turn it into a closed form, using the
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