In SimplifyICmpOperands, avoid needlessly swapping the operands in the
case where both are addrecs in unrelated loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102924 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index fea0a7a..2a502cd 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -4783,13 +4783,16 @@
}
// If we're comparing an addrec with a value which is loop-invariant in the
- // addrec's loop, put the addrec on the left.
- if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS))
- if (LHS->isLoopInvariant(AR->getLoop())) {
+ // addrec's loop, put the addrec on the left. Also make a dominance check,
+ // as both operands could be addrecs loop-invariant in each other's loop.
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(RHS)) {
+ const Loop *L = AR->getLoop();
+ if (LHS->isLoopInvariant(L) && LHS->properlyDominates(L->getHeader(), DT)) {
std::swap(LHS, RHS);
Pred = ICmpInst::getSwappedPredicate(Pred);
Changed = true;
}
+ }
// If there's a constant operand, canonicalize comparisons with boundary
// cases, and canonicalize *-or-equal comparisons to regular comparisons.