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Optimize this code somewhat by taking advantage of the fact 

that the operands are sorted.

llvm-svn: 105546
This commit is contained in:
Dan Gohman 2010-06-07 19:20:57 +00:00
parent cfcd0e12cf
commit 3553feed79
1 changed files with 13 additions and 7 deletions
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20
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -1101,8 +1101,19 @@ CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M,
ScalarEvolution &SE) {
bool Interesting = false;
// Iterate over the add operands.
for (unsigned i = 0, e = NumOperands; i != e; ++i) {
// Iterate over the add operands. They are sorted, with constants first.
unsigned i = 0;
while (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
++i;
// Pull a buried constant out to the outside.
if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
Interesting = true;
AccumulatedConstant += Scale * C->getValue()->getValue();
}
// Next comes everything else. We're especially interested in multiplies
// here, but they're in the middle, so just visit the rest with one loop.
for (; i != NumOperands; ++i) {
const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(Ops[i]);
if (Mul && isa<SCEVConstant>(Mul->getOperand(0))) {
APInt NewScale =
@ -1130,11 +1141,6 @@ CollectAddOperandsWithScales(DenseMap<const SCEV *, APInt> &M,
Interesting = true;
}
}
} else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(Ops[i])) {
// Pull a buried constant out to the outside.
if (Scale != 1 || AccumulatedConstant != 0 || C->getValue()->isZero())
Interesting = true;
AccumulatedConstant += Scale * C->getValue()->getValue();
} else {
// An ordinary operand. Update the map.
std::pair<DenseMap<const SCEV *, APInt>::iterator, bool> Pair =