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Re: Loop unrolling-related SPEC regressions?

Dale Johannesen <> writes:

> Intelligent use of profiling info from the first pass is
> important.  You'll see the published numbers do this.
> Last time I looked gcc used this only for branch
> straightening; it can also be used effectively to
> drive inlining and register allocation.

AFAIK the infrastructure is there, it only needs to be used for
inlining - and also in the new register allocator.  Michal, is this

> crafty is heavily dependent on efficiency of "long long".
> It's a chess program, full of 64-bit bitmasks.
> eon is the only one in C++.  If there are any problems
> in exception handling they will show up here.  The program
> does not actually throw any exceptions, so turning off
> the handling for peak may help (SPEC won't let you turn
> it off for base).  Good inlining decisions are also important.

The inline change brought in August by Kurt Garloff brought a real
performance improvement, check my graphs at

> the two most heavily executed functions in perl are big;
> IME register allocation & scheduling don't always work
> well for big functions.  They also both call setjmp; if
> this disables any substantial amount of optimization it
> will hurt.
> vortex accesses a huge amount of virtual memory.  Good
> malloc/free performance is critical.

 Andreas Jaeger
  SuSE Labs

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