From 2541060ae473bfb33b7b8c4bf49f4ad339634b44 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= Date: Mon, 25 May 2020 21:21:49 +0200 Subject: [PATCH] readme: document work around for GCC 10.1 O2+PGO regression --- README.md | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/README.md b/README.md index 9637c409..9c7e19cb 100644 --- a/README.md +++ b/README.md @@ -317,8 +317,11 @@ A note on compilers; in general, foot runs **much** faster when compiled with gcc instead of clang. A profile-guided gcc build can be more than twice as fast as a clang build. -**Note** GCC 10.1 has a performance regression that affects foot. A -PGO build is about 30-40% slower with GCC 10.1 compared to GCC 9.3. +**Note** GCC 10.1 has a performance regression that severely affects +foot when doing PGO builds and building with `-O2`; it is about 30-40% +slower compared to GCC 9.3. + +The work around is simple: make sure you build with `-O3`. ## Installing