[PATCH] D30572: Remove equal BBs from a function

[Andrew V. Tischenko via Phabricator via llvm-commits]

avt77 added a comment.

Hi All,
Reading the sources of TailMerging Pass I discovered that it has special switch "tail-merge-size" allowing to resolve the issue from loop-serch.ll test. The default value of the switch is 3 but if I change it as 2 then everything works fine.
Because of that I decided to abandon this review :-(
I'm going to investigate the possibility to change the default value. If it is not allowed for any reasons (compile time, target specific requirements, etc.) I'll implement special hook in Target as it's suggested in sources.

Any thoughts about possible default value for "tail-merge-size"? I suppose it could be 1 because we can have a lot of BBs with single "ret" (or "unconditional jump" or ...) instruction and we'd like to merge all such BBs. The compilation time should not increase dramatically (from my point of view) but we need investigations of course.


https://reviews.llvm.org/D30572