[all-commits] [llvm/llvm-project] 160675: [SystemZ] Mark unsaved argument R6 as live through...

[Jonas Paulsson via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1606755da0e4fb362c88fdf02373f0dc3e4eef8f
      https://github.com/llvm/llvm-project/commit/1606755da0e4fb362c88fdf02373f0dc3e4eef8f
  Author: Jonas Paulsson <paulsson at linux.vnet.ibm.com>
  Date:   2020-10-21 (Wed, 21 Oct 2020)

  Changed paths:
    M llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
    A llvm/test/CodeGen/SystemZ/frame-26.mir

  Log Message:
  -----------
  [SystemZ] Mark unsaved argument R6 as live throughout function.

For historical reasons, the R6 register is a callee-saved argument
register. This means that if it is used to pass an argument to a function
that does not clobber it, it is live throughout the function.

This patch makes sure that in this special case any kill flags of it are
removed.

Review: Ulrich Weigand, Eli Friedman

Differential Revision: https://reviews.llvm.org/D89451