[llvm-dev] Scaling to many basic blocks

[Joerg Sonnenberger via llvm-dev]

On Sun, Aug 23, 2015 at 09:53:16PM -0700, Mehdi Amini wrote:
> 
> > On Aug 23, 2015, at 11:35 AM, Joerg Sonnenberger via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> > 
> > On Sun, Aug 23, 2015 at 01:46:12AM +0100, Russell Wallace via llvm-dev wrote:
> >> On Sat, Aug 22, 2015 at 11:57 PM, Michael Zolotukhin <mzolotukhin at apple.com>
> >> wrote:
> >> 
> >>> Hi,
> >>> 
> >>> Several passes would have troubles with such code (namely, GVN and
> >>> JumpThreading).
> >> 
> >> 
> >> Can you just choose not to run those particular passes? I suppose the big
> >> problem would be if there's a problem with the code generation and related
> >> stuff like instruction scheduling and register allocation - is that likely
> >> to be the case?
> > 
> > One problematic pass right now is correlated value propogation. The sad
> > part is that at least from clang it can't be disabled short of -O0 :(
> > I have a patch in my tree to at least be able to disable it with -mllvm
> > magic, but Chandler didn't like it for the obvious reasons for in-tree.
> > 
> > It would be really nice if someone could (finally) add the proper memory
> > and compute time bounding to that pass.
> 
> 
> Is there already a PR open on https://llvm.org/bugs/ ? Ideally with a pre-processed source to feed to clang to reproduce.

Sure, https://llvm.org/bugs/show_bug.cgi?id=10584

Joerg