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Re: [trunk<-vta] Re: [vta] stabilize loop-unroll across insn uid variations


On Mon, Jun 1, 2009 at 10:14 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Oct ?7, 2008, Alexandre Oliva <aoliva@redhat.com> wrote:
>
>> compare-debug detected some differences causes by RTL loop unrolling,
>> because debug insns changed the insn uids it uses as hashes. ?Because
>> of this change, insns were walked in different orders, and different
>> decisions were made.
>
>> I couldn't find a simple way to stabilize the uids or compute good and
>> stable hashes without using them. ?This is the only place AFAICT that
>> uses them as hashes, so I came up with a solution that will waste a
>> bit of memory, but that will ensure we walk the insns in a consistent
>> order, regardless of changes to insn uids. ?To make up for the
>> (little) additional memory, we should get a slight speedup when
>> walking the lists with type-safe inlinable calls, rather than walking
>> every entry of a hashtable that's designed to be about half empty,
>> with a type-unsafe non-inlinable callback.
>
> Ok for trunk?

I'll defer to Zdenek.

Richard.


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