[all-commits] [llvm/llvm-project] a11e5b: [InstCombine][X86] simplifyX86immShift - handle va...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: a11e5b32dfb1fbdb72f00440351f9e3956788d13
      https://github.com/llvm/llvm-project/commit/a11e5b32dfb1fbdb72f00440351f9e3956788d13
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-03-19 (Thu, 19 Mar 2020)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

  Log Message:
  -----------
  [InstCombine][X86] simplifyX86immShift - handle variable out-of-range vector shift by immediate amounts (PR40391)

If we know the SSE shift amount is out of range then we can simplify to zero value (logical) or a 'signsplat' bitwidth-1 shift (arithmetic). This allows us to remove the equivalent ConstantInt constant folding path from simplifyX86immShift.