Building libreoffice with GCC 6 and LTO

New GCC is just around the corner. For me, as a GCC developer, this means a period of bugfixing, benchmarking and fine-tuning. Two years ago I wrote about my experiment  of building libreoffice with link time optimization (LTO). At that time LTO just got into shape of being able to build such large applications. Since that I am keeping my eye on this and try to be sure LTO keeps improving. I did not have time to publish any tests for GCC 5. Here is update for current trunk of GCC 6 compared to GCC 4.9.0, GCC 5.3, LLVM 3.5 and trunk.

Linktime optimization in GCC, part 3 - LibreOffice

After Firefox, I decided to look into LibreOffice performance with link time optimizations (LTO) and profile feedback (FDO). This post was in works since April, so my setup is not exactly bleeding edge - GCC 4.9.1 prerelease, LLVM 3.5 and LibreOffice checkout from April. Some real world issues (like a wedding) interrupted my work, however the data presented should be still relevant and interesting.

Linktime optimization in GCC, part 2 - Firefox

This time I will write about building Firefox with LTO. Firefox is one of largest binaries on my hard drive (beaten only by Chromium) so it is an excellent stress test. Taras Glek and I started to work on getting Firefox to build well in 2009 (see original paper from 2010), however for all those years I was mostly chasing correctness and compile time/memory usage issues. Markus Trippelsdorf was instrumental to keep the project going. In parallel Rafael Espindola did same effort of getting Firefox to work with LLVM and LTO