On Sun, Nov 8, 2009 at 18:03, Basile STARYNKEVITCH <bas...@starynkevitch.net> wrote:
> Perhaps the question is when not to use -flto and use -fwhopr instead? I don't think anyone has systematically tried to determine these limits. The original design tried to address a specific instance of a program with about 400 million callgraph nodes. At the time, -flto was running out of virtual addressing space to hold it (the gcc binary was 32 bits), but it could be processed with -fwhopr. The current implementation of -fwhopr is incomplete, however. It needs fixes to the pass manager to properly apply all IPA passes (and associated bug fixes). I would not use it in 4.5. Richi has made numerous fixes to symbol/type handling, so -flto is now more memory efficient than it was when I last tried it on a large application. Diego.
