[all-commits] [llvm/llvm-project] bf2048: [msan] Change logic of ClInstrumentationWithCallTh...

[Vitaly Buka via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bf204881b6376c57aa56668612321658c4606e38
      https://github.com/llvm/llvm-project/commit/bf204881b6376c57aa56668612321658c4606e38
  Author: Vitaly Buka <vitalybuka at google.com>
  Date:   2022-09-14 (Wed, 14 Sep 2022)

  Changed paths:
    M llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
    M llvm/test/Instrumentation/MemorySanitizer/with-call-type-size.ll

  Log Message:
  -----------
  [msan] Change logic of ClInstrumentationWithCallThreshold

According to logs, ClInstrumentationWithCallThreshold is workaround
for slow backend with large number of basic blocks.
However, I can't reproduce that one, but I see significant slowdown
after ClCheckConstantShadow. Without ClInstrumentationWithCallThreshold
compiler is able to eliminate many of the branches.

So maybe we should drop ClInstrumentationWithCallThreshold completly.

For now I just change the logic to ignore constant shadow so it will
not trigger callback fallback too early.

Reviewed By: kstoimenov

Differential Revision: https://reviews.llvm.org/D133880