[PATCH] D28746: Mention ThinLTO with PGO in ReleaseNotes 4.0

[Teresa Johnson via Phabricator via cfe-commits]

tejohnson added a comment.

In https://reviews.llvm.org/D28746#646793, @Prazek wrote:

> Maybe I should change ThinLTO for '-flto=thin' and also mention this improvement in LLVM release notes?
>
> BTW '-flto=thin' is not documented in UsersManual


It's documented here:

  http://clang.llvm.org/docs/index.html

and here:

  http://clang.llvm.org/docs/CommandGuide/clang.html

but not (yet) here:

  http://clang.llvm.org/docs/UsersManual.html

I can add that.

Thanks!



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Comment at: docs/ReleaseNotes.rst:69
+  called from cold callsite.
+
 
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mehdi_amini wrote:
> We need to mention ThinLTO in the Release Notes, so thanks for initiating this. 
> We likely should go with a paragraph summarizing the improvements, I don't know though if there is anything else than 1) PGO and 2) Significant build-time and binary-size improvements with debug-info.
> 
Yes this is a good start. One of the big improvements from PGO is the integration with indirect call promotion. I would suggest something like:

Improvements to ThinLTO (-flto=thin):
- Integration with profile data. When available, profile data enables more accurate function importing decisions, as well as cross-module indirect call promotion.
- Significant build-time and binary-size improvements when compiling with debug info (-g).


https://reviews.llvm.org/D28746