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Teach SCEV::isLoopInvariant and SCEV::hasComputableLoopEvolution 

about the convention from LoopInfo that a null Loop* means the entire
function body.

llvm-svn: 72152
This commit is contained in:
Dan Gohman 2009-05-20 01:01:24 +00:00
parent b9a4a57699
commit 9cbf850506
1 changed files with 6 additions and 2 deletions
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8
llvm/lib/Analysis/ScalarEvolution.cpp
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@ -388,7 +388,9 @@ replaceSymbolicValuesWithConcrete(const SCEVHandle &Sym,
bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
// This recurrence is invariant w.r.t to QueryLoop iff QueryLoop doesn't
// contain L and if the start is invariant.
return !QueryLoop->contains(L->getHeader()) &&
// Add recurrences are never invariant in the function-body (null loop).
return QueryLoop &&
!QueryLoop->contains(L->getHeader()) &&
getOperand(0)->isLoopInvariant(QueryLoop);
}
@ -410,8 +412,10 @@ SCEVUnknown::~SCEVUnknown() { SCEVUnknowns->erase(V); }
bool SCEVUnknown::isLoopInvariant(const Loop *L) const {
// All non-instruction values are loop invariant. All instructions are loop
// invariant if they are not contained in the specified loop.
// Instructions are never considered invariant in the function body
// (null loop) because they are defined within the "loop".
if (Instruction *I = dyn_cast<Instruction>(V))
return !L->contains(I->getParent());
return L && !L->contains(I->getParent());
return true;
}