[PATCH] D22537: [InstSimplify] recognize trunc + icmp sgt/slt variants of select simplifications (PR28466)

[Sanjay Patel via llvm-commits]

spatel created this revision.
spatel added reviewers: majnemer, eli.friedman.
spatel added a subscriber: llvm-commits.
Herald added a subscriber: mcrosier.

rL245171 exposed a hole in InstSimplify that manifested in a strange way in PR28466:
https://llvm.org/bugs/show_bug.cgi?id=28466

It's possible to use trunc + icmp sgt/slt in place of an and + icmp eq/ne, so we need to recognize that pattern to eliminate selects that are choosing between some value and some bitmasked version of that value.

https://reviews.llvm.org/D22537

Files:
  lib/Analysis/InstructionSimplify.cpp
  test/Transforms/InstSimplify/select.ll

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