tree c060df72c78b35ee0942dac9e9408add9fb55168
parent 989bed989a41732d1b70314bd9063ccd6e74fe5c
author Eli Friedman <efriedma@quicinc.com> 1578958365 -0800
committer Eli Friedman <efriedma@quicinc.com> 1578963341 -0800

[GlobalISel] Change representation of shuffle masks in MachineOperand.

We're planning to remove the shufflemask operand from ShuffleVectorInst
(D72467); fix GlobalISel so it doesn't depend on that Constant.

The change to prelegalizercombiner-shuffle-vector.mir happens because
the input contains a literal "-1" in the mask (so the parser/verifier
weren't really handling it properly). We now treat it as equivalent to
"undef" in all contexts.

Differential Revision: https://reviews.llvm.org/D72663