mirror of
https://github.com/RPCS3/llvm.git
synced 2025-05-13 08:56:04 +00:00
2e1df5f759
is enabled. We can save memory and reduce binary size significantly by enabling ProfileSampleAccurate. However when ProfileSampleAccurate is true, function without sample will be regarded as cold and this could potentially cause performance regression. To minimize the potential negative performance impact, we want to be a little conservative here saying if a function shows up in the profile, no matter as outline instance, inline instance or call targets, treat the function as not being cold. This will handle the cases such as most callsites of a function are inlined in sampled binary (thus outline copy don't get any sample) but not inlined in current build (because of source code drift, imprecise debug information, or the callsites are all cold individually but not cold accumulatively...), so that the outline function showing up as cold in sampled binary will actually not be cold after current build. After the change, such function will be treated as not cold even profile-sample-accurate is enabled. At the same time we lower the hot criteria of callsiteIsHot check when profile-sample-accurate is enabled. callsiteIsHot is used to determined whether a callsite is hot and qualified for early inlining. When profile-sample-accurate is enabled, functions without profile will be regarded as cold and much less inlining will happen in CGSCC inlining pass, so we can worry less about size increase and be aggressive to allow more early inlining to happen for warm callsites and it is helpful for performance overall. Differential Revision: https://reviews.llvm.org/D67561 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372232 91177308-0d34-0410-b5e6-96231b3b80d8
The LLVM Compiler Infrastructure ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.