[all-commits] [llvm/llvm-project] d9f064: [InstCombine] visitTrunc - trunc(shl(X, C)) --> sh...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: d9f064dc0bd4ea4a29a20068835b37e973be907f
      https://github.com/llvm/llvm-project/commit/d9f064dc0bd4ea4a29a20068835b37e973be907f
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-10-08 (Thu, 08 Oct 2020)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
    M llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest-with-truncation-shl.ll
    M llvm/test/Transforms/InstCombine/shift-amount-reassociation-with-truncation-shl.ll
    M llvm/test/Transforms/InstCombine/trunc.ll

  Log Message:
  -----------
  [InstCombine] visitTrunc - trunc(shl(X, C)) --> shl(trunc(X),trunc(C)) vector support

Annoyingly vectors aren't supported by shouldChangeType(), but we have precedents for always performing this on vector types (e.g. narrowBinOp).

Differential Revision: https://reviews.llvm.org/D89067