[PATCH] D45863: [InstCombine] Support BitTests in ThreeWayComparison. Mismatched types

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev created this revision.
mkazantsev added reviewers: craig.topper, lebedev.ri, spatel, reames.
mkazantsev added dependencies: D45856: [InstCombine] Support BitTests in ThreeWayComparison. General case, part 2, D45862: [InstCombine] Relax restriction in foldSelectInstWithICmp for sake of smaller code size.

In this patch we continue supporting BitTests of the highest bit in the ThreeWayComparison
matcher in the InstCombine (see problem's description in the message of https://reviews.llvm.org/D45854).

This patch adds support for the transform of

  %c2 = icmp slt i64 %a, 0
  %select1 = select i1 %c2, i32 %Less, i32 %Greater

to

  (trunc (%a s>> 64) to i32) - (%Less - %Greater) + %Greater


https://reviews.llvm.org/D45863

Files:
  lib/Transforms/InstCombine/InstCombineCompares.cpp
  test/Transforms/InstCombine/three-way-comparison.ll

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