[PATCH] D82721: [ScalarEvolution] createSCEV(): MatchBinaryOp(): recognize `urem` disguised as an `srem`

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: mkazantsev, efriedma, nikic, reames.
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================
Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:4345
 
+  case Instruction::SRem: {
+    // If the sign bits of both operands are zero (i.e. we can prove they are
----------------
This is a pretty verbatim copypasta from `InstCombiner::visitSRem()`


While InstCombine trivially converts that `srem` into a `urem`,
it might happen later than wanted, in particular i'd like
for that to happen on  https://godbolt.org/z/bwuEmJ test case
early in pipeline, before first instcombine run, just before `-mem2reg`.

SCEV should recognize this case natively.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D82721

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/srem.ll

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