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extract some code into a method, no functionality change

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26755 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-03-14 07:11:11 +00:00
parent ad5a3a0265
commit 895b392269
1 changed files with 56 additions and 50 deletions
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106
lib/Transforms/Scalar/Reassociate.cpp
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@ -78,6 +78,7 @@ namespace {
private:
void BuildRankMap(Function &F);
unsigned getRank(Value *V);
void ReassociateExpression(BinaryOperator *I);
void RewriteExprTree(BinaryOperator *I, unsigned Idx,
std::vector<ValueEntry> &Ops);
Value *OptimizeExpression(BinaryOperator *I, std::vector<ValueEntry> &Ops);
@ -752,57 +753,62 @@ void Reassociate::ReassociateBB(BasicBlock *BB) {
cast<Instruction>(I->use_back())->getOpcode() == Instruction::Sub)
continue;
// First, walk the expression tree, linearizing the tree, collecting
std::vector<ValueEntry> Ops;
LinearizeExprTree(I, Ops);
ReassociateExpression(I);
}
}
DEBUG(std::cerr << "RAIn:\t"; PrintOps(I, Ops);
std::cerr << "\n");
// Now that we have linearized the tree to a list and have gathered all of
// the operands and their ranks, sort the operands by their rank. Use a
// stable_sort so that values with equal ranks will have their relative
// positions maintained (and so the compiler is deterministic). Note that
// this sorts so that the highest ranking values end up at the beginning of
// the vector.
std::stable_sort(Ops.begin(), Ops.end());
// OptimizeExpression - Now that we have the expression tree in a convenient
// sorted form, optimize it globally if possible.
if (Value *V = OptimizeExpression(I, Ops)) {
// This expression tree simplified to something that isn't a tree,
// eliminate it.
DEBUG(std::cerr << "Reassoc to scalar: " << *V << "\n");
I->replaceAllUsesWith(V);
RemoveDeadBinaryOp(I);
continue;
}
// We want to sink immediates as deeply as possible except in the case where
// this is a multiply tree used only by an add, and the immediate is a -1.
// In this case we reassociate to put the negation on the outside so that we
// can fold the negation into the add: (-X)*Y + Z -> Z-X*Y
if (I->getOpcode() == Instruction::Mul && I->hasOneUse() &&
cast<Instruction>(I->use_back())->getOpcode() == Instruction::Add &&
isa<ConstantInt>(Ops.back().Op) &&
cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) {
Ops.insert(Ops.begin(), Ops.back());
Ops.pop_back();
}
DEBUG(std::cerr << "RAOut:\t"; PrintOps(I, Ops);
std::cerr << "\n");
if (Ops.size() == 1) {
// This expression tree simplified to something that isn't a tree,
// eliminate it.
I->replaceAllUsesWith(Ops[0].Op);
RemoveDeadBinaryOp(I);
} else {
// Now that we ordered and optimized the expressions, splat them back into
// the expression tree, removing any unneeded nodes.
RewriteExprTree(I, 0, Ops);
}
void Reassociate::ReassociateExpression(BinaryOperator *I) {
// First, walk the expression tree, linearizing the tree, collecting
std::vector<ValueEntry> Ops;
LinearizeExprTree(I, Ops);
DEBUG(std::cerr << "RAIn:\t"; PrintOps(I, Ops);
std::cerr << "\n");
// Now that we have linearized the tree to a list and have gathered all of
// the operands and their ranks, sort the operands by their rank. Use a
// stable_sort so that values with equal ranks will have their relative
// positions maintained (and so the compiler is deterministic). Note that
// this sorts so that the highest ranking values end up at the beginning of
// the vector.
std::stable_sort(Ops.begin(), Ops.end());
// OptimizeExpression - Now that we have the expression tree in a convenient
// sorted form, optimize it globally if possible.
if (Value *V = OptimizeExpression(I, Ops)) {
// This expression tree simplified to something that isn't a tree,
// eliminate it.
DEBUG(std::cerr << "Reassoc to scalar: " << *V << "\n");
I->replaceAllUsesWith(V);
RemoveDeadBinaryOp(I);
return;
}
// We want to sink immediates as deeply as possible except in the case where
// this is a multiply tree used only by an add, and the immediate is a -1.
// In this case we reassociate to put the negation on the outside so that we
// can fold the negation into the add: (-X)*Y + Z -> Z-X*Y
if (I->getOpcode() == Instruction::Mul && I->hasOneUse() &&
cast<Instruction>(I->use_back())->getOpcode() == Instruction::Add &&
isa<ConstantInt>(Ops.back().Op) &&
cast<ConstantInt>(Ops.back().Op)->isAllOnesValue()) {
Ops.insert(Ops.begin(), Ops.back());
Ops.pop_back();
}
DEBUG(std::cerr << "RAOut:\t"; PrintOps(I, Ops);
std::cerr << "\n");
if (Ops.size() == 1) {
// This expression tree simplified to something that isn't a tree,
// eliminate it.
I->replaceAllUsesWith(Ops[0].Op);
RemoveDeadBinaryOp(I);
} else {
// Now that we ordered and optimized the expressions, splat them back into
// the expression tree, removing any unneeded nodes.
RewriteExprTree(I, 0, Ops);
}
}