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Assign finer grained ranks, make sure to reassociate top-level after reassociating bottom level

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7787 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-08-12 20:14:27 +00:00
parent e132d95b62
commit 6007cb6c4d
1 changed files with 11 additions and 7 deletions
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18
lib/Transforms/Scalar/Reassociate.cpp
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@ -57,20 +57,20 @@ namespace {
Pass *createReassociatePass() { return new Reassociate(); }
void Reassociate::BuildRankMap(Function &F) {
unsigned i = 1;
unsigned i = 2;
ReversePostOrderTraversal<Function*> RPOT(&F);
for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(),
E = RPOT.end(); I != E; ++I)
RankMap[*I] = ++i;
RankMap[*I] = ++i << 16;
}
unsigned Reassociate::getRank(Value *V) {
if (isa<Argument>(V)) return 1; // Function argument...
if (Instruction *I = dyn_cast<Instruction>(V)) {
// If this is an expression, return the MAX(rank(LHS), rank(RHS)) so that we
// can reassociate expressions for code motion! Since we do not recurse for
// PHI nodes, we cannot have infinite recursion here, because there cannot
// be loops in the value graph that do not go through PHI nodes.
// If this is an expression, return the 1+MAX(rank(LHS), rank(RHS)) so that
// we can reassociate expressions for code motion! Since we do not recurse
// for PHI nodes, we cannot have infinite recursion here, because there
// cannot be loops in the value graph that do not go through PHI nodes.
//
if (I->getOpcode() == Instruction::PHINode ||
I->getOpcode() == Instruction::Alloca ||
@ -87,7 +87,10 @@ unsigned Reassociate::getRank(Value *V) {
i != e && Rank != MaxRank; ++i)
Rank = std::max(Rank, getRank(I->getOperand(i)));
return CachedRank = Rank;
DEBUG(std::cerr << "Calculated Rank[" << V->getName() << "] = "
<< Rank+1 << "\n");
return CachedRank = Rank+1;
}
// Otherwise it's a global or constant, rank 0.
@ -145,6 +148,7 @@ bool Reassociate::ReassociateExpr(BinaryOperator *I) {
// Since we modified the RHS instruction, make sure that we recheck it.
ReassociateExpr(LHSI);
ReassociateExpr(I);
return true;
}
}