[all-commits] [llvm/llvm-project] 105e5c: [ValueTracking] Add DemandedElts support to comput...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 105e5c940cc026f6761024d3945d7411b1978fdb
      https://github.com/llvm/llvm-project/commit/105e5c940cc026f6761024d3945d7411b1978fdb
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-02-01 (Sat, 01 Feb 2020)

  Changed paths:
    M llvm/lib/Analysis/ValueTracking.cpp
    M llvm/test/Transforms/InstCombine/nsw.ll
    M llvm/test/Transforms/InstCombine/shift-add.ll
    M llvm/test/Transforms/LoopVectorize/X86/small-size.ll
    M llvm/test/Transforms/LoopVectorize/X86/x86-interleaved-accesses-masked-group.ll

  Log Message:
  -----------
  [ValueTracking] Add DemandedElts support to computeKnownBits/ComputeNumSignBits (PR36319)

This patch adds initial support for a DemandedElts mask to the internal computeKnownBits/ComputeNumSignBits methods, matching the SelectionDAG and GlobalISel equivalents.

So far only a couple of instructions have been setup to handle the DemandedElts, the remainder still using the existing 'all elements' default. The plan is to extend support as we have test coverage.

Differential Revision: https://reviews.llvm.org/D73435