[MCA] Add support for in-order CPUs

Authored by asavonic on Dec 29 2020, 8:49 AM.


[MCA] Add support for in-order CPUs

This patch adds a pipeline to support in-order CPUs such as ARM

In-order pipeline implements a simplified version of Dispatch,
Scheduler and Execute stages as a single stage. Entry and Retire
stages are common for both in-order and out-of-order pipelines.

Differential Revision: https://reviews.llvm.org/D94928