[PATCH] D143883: [InstCombine] canonicalize urem as cmp+select

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp:1792
+  if (match(Op0, m_NUWAdd(m_Value(X), m_One())) &&
+      simplifyICmpWithDominatingAssume(ICmpInst::ICMP_ULT, X, Op1, SQ, &I)) {
+    Value *Cmp = Builder.CreateICmpEQ(Op0, Op1);
----------------
Allen wrote:
> nikic wrote:
> > Why is this specific to assumes? Can we do a generic simplifyICmp? (If we do so, Op0 needs to be frozen.)
> Apply your comment, thanks
Would this be better? I always hate to see isa<> + cast<> pairs - it feels like we're duplicating work.
```
if (auto *CVal = dyn_cast_or_null<Constant>(Val)) {
  if (CVal->isOneValue()) {
  }
}
```


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  https://reviews.llvm.org/D143883/new/

https://reviews.llvm.org/D143883