This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

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

On Mon, Jun 1, 2009 at 10:14 AM, Alexandre Oliva <> wrote:
> On Oct ?7, 2008, Alexandre Oliva <> 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.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]