[PATCH] D49994: Allow constraining virtual register's class within reason

[Alexey Zhikhartsev via Phabricator via llvm-commits]

alexey.zhikhar added a comment.

@jonpa Jonas, I see a different assembly in one of SystemZ unit tests; my memory of Z is pretty fuzzy, so could you please make sense of the change to see whether it is reasonable?

Test name is `CodeGen/SystemZ/cond-move-03.ll`, test case `f2()`.

Before the change:

          #APP
          dummy %r0 
          #NO_APP
          #APP
          stepa %r1 
          #NO_APP
          #APP
          stepb %r0 
          #NO_APP
          clijhe  %r2, 42, .LBB1_2
  # %bb.1:
          risblg  %r0, %r1, 0, 159, 32
  .LBB1_2:
          risbhg  %r1, %r0, 0, 159, 32
          #APP
          stepc %r1 
          #NO_APP
          #APP
          dummy %r0 
          #NO_APP
          br      %r14

After the change:

  #APP
  dummy %r0 
  #NO_APP
  #APP
  stepa %r1 
  #NO_APP
  #APP
  stepb %r0 
  #NO_APP
  clfi    %r2, 42
  risbhg  %r2, %r0, 0, 159, 32
  locfhrl %r2, %r1 
  #APP
  stepc %r2 
  #NO_APP
  #APP
  dummy %r0 
  #NO_APP
  br      %r14


Repository:
  rL LLVM

https://reviews.llvm.org/D49994