When looking for loop-invariant users, look through no-op instructions,

so that an unfortunately placed bitcast doesn't pin a value in a
register.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100883 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-04-09 19:12:34 +00:00
parent 232c8b4d26
commit 4a2a683366

View File

@ -1947,9 +1947,17 @@ LSRInstance::CollectLoopInvariantFixupsAndFormulae() {
continue;
// Ignore uses which are part of other SCEV expressions, to avoid
// analyzing them multiple times.
if (SE.isSCEVable(UserInst->getType()) &&
!isa<SCEVUnknown>(SE.getSCEV(const_cast<Instruction *>(UserInst))))
continue;
if (SE.isSCEVable(UserInst->getType())) {
const SCEV *UserS = SE.getSCEV(const_cast<Instruction *>(UserInst));
// If the user is a no-op, look through to its uses.
if (!isa<SCEVUnknown>(UserS))
continue;
if (UserS == U) {
Worklist.push_back(
SE.getUnknown(const_cast<Instruction *>(UserInst)));
continue;
}
}
// Ignore icmp instructions which are already being analyzed.
if (const ICmpInst *ICI = dyn_cast<ICmpInst>(UserInst)) {
unsigned OtherIdx = !UI.getOperandNo();