Optimize this code somewhat by taking advantage of the fact
that the operands are sorted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105546 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index ab90939..d0e5e37 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -1101,8 +1101,19 @@
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 @@
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 =