[all-commits] [llvm/llvm-project] edab7d: Disable hoisting MI to hotter basic blocks

[Victor Huang via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: edab7dd426249bd40059b49b255ba9cc5b784753
      https://github.com/llvm/llvm-project/commit/edab7dd426249bd40059b49b255ba9cc5b784753
  Author: Victor Huang <victorh at recycler.canlab.ibm.com>
  Date:   2019-11-11 (Mon, 11 Nov 2019)

  Changed paths:
    M llvm/lib/CodeGen/MachineLICM.cpp
    A llvm/test/CodeGen/PowerPC/DisableHoistingDueToBlockHotnessNoProfileData.mir
    A llvm/test/CodeGen/PowerPC/DisableHoistingDueToBlockHotnessProfileData.mir

  Log Message:
  -----------
  Disable hoisting MI to hotter basic blocks

In current Hoist() function of machine licm pass, it will not check the source and destination basic block frequencies that a instruction is hoisted from/to.
There is a chance that instruction is hoisted from a cold to a hot basic block.

In this patch, we add options to disable machine instruction hoisting if destination block is hotter.

Differential Revision: https://reviews.llvm.org/D63676