[all-commits] [llvm/llvm-project] d2533d: [PowerPC] Fix crash for shuffle canonicalization w...

[Nemanja Ivanovic via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: d2533d96e14118a86904a69fd2a192c008642f14
      https://github.com/llvm/llvm-project/commit/d2533d96e14118a86904a69fd2a192c008642f14
  Author: Nemanja Ivanovic <nemanja.i.ibm at gmail.com>
  Date:   2020-06-29 (Mon, 29 Jun 2020)

  Changed paths:
    M llvm/lib/Target/PowerPC/PPCISelLowering.cpp
    M llvm/test/CodeGen/PowerPC/canonical-merge-shuffles.ll

  Log Message:
  -----------
  [PowerPC] Fix crash for shuffle canonicalization with elt 0 from RHS

Commit 1fed131660b2 assumed that shuffle vector canonicalization will
always ensure that the shuffle mask will be ordered so that element
zero comes from the LHS vector. However there is code out there for
which this is not the case. This patch simply removes that unsafe
assumption and makes the code work regardless of the source of the
first element.