[all-commits] [llvm/llvm-project] 6f6159: [InstrProf] Add option to avoid instrumenting smal...

[Ellis Hoag via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 6f61594d8cd4cca559b3c87f2fa47d4bdc017c82
      https://github.com/llvm/llvm-project/commit/6f61594d8cd4cca559b3c87f2fa47d4bdc017c82
  Author: Ellis Hoag <ellis.sparky.hoag at gmail.com>
  Date:   2022-08-17 (Wed, 17 Aug 2022)

  Changed paths:
    M llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
    A llvm/test/Transforms/PGOProfile/function_size_threshold.ll

  Log Message:
  -----------
  [InstrProf] Add option to avoid instrumenting small functions

If a function only has a few instructions, instrumentation can significantly increase the size and performance overhead of that function. Add the `-pgo-function-size-threshold` option to select a size threshold so these small functions are not instrumented.

A similar option `-fxray-instruction-threshold=<N>` is used for XRay to reduce binary size overhead [1].

[1] https://www.llvm.org/docs/XRay.html

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D131816