[PATCH] D104741: [SCEV] Support single-cond range check idiom in applyLoopGuards.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:13671
+          C1->getValue()->isMinusOne() && Predicate == CmpInst::ICMP_ULT &&
+          C2 && !C2->getAPInt().isMaxValue() && !C2->getAPInt().isNullValue()) {
+        auto *LHSUnknown = dyn_cast<SCEVUnknown>(AddExpr->getOperand(1));
----------------
Instead of trying to special-case `(-1 + X) u< C`, could you use ConstantRange::makeExactICmpRegion?  Not that this necessarily needs to be generalized, but it would be easier to follow the logic, I think.


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  https://reviews.llvm.org/D104741/new/

https://reviews.llvm.org/D104741