[all-commits] [llvm/llvm-project] 31bd15: [PGO][InstrProf] Do not promote count if the exit ...

[xur-llvm via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 31bd15c562449954d8211c067fc38b1907d60615
      https://github.com/llvm/llvm-project/commit/31bd15c562449954d8211c067fc38b1907d60615
  Author: Rong Xu <xur at google.com>
  Date:   2020-07-24 (Fri, 24 Jul 2020)

  Changed paths:
    M llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
    M llvm/test/Transforms/PGOProfile/counter_promo.ll
    A llvm/test/Transforms/PGOProfile/not_promote_ret_exit.ll

  Log Message:
  -----------
  [PGO][InstrProf] Do not promote count if the exit blocks contains ret instruction

Skip profile count promotion if any of the ExitBlocks contains a ret
instruction. This is to prevent dumping of incomplete profile -- if the
the loop is a long running loop and dump is called in the middle
of the loop, the result profile is incomplete.

ExitBlocks containing a ret instruction is an indication of a long running
loop -- early exit to error handling code.

Differential Revision: https://reviews.llvm.org/D84379