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Re: [tree-ssa] Avoid nondeterminism in tree-ssanames
- From: law at redhat dot com
- To: Andrew MacLeod <amacleod at redhat dot com>
- Cc: Gerald Pfeifer <gp at suse dot de>, Jan Hubicka <jh at suse dot cz>, Diego Novillo <dnovillo at redhat dot com>, Geoff Keating <geoffk at geoffk dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 03 Dec 2003 11:48:30 -0700
- Subject: Re: [tree-ssa] Avoid nondeterminism in tree-ssanames
- Reply-to: law at redhat dot com
In message <1070476847.9315.2389.camel@p4>, Andrew MacLeod writes:
>On Wed, 2003-12-03 at 13:39, Gerald Pfeifer wrote:
>> On Mon, 1 Dec 2003, Jan Hubicka wrote:
>> > It makes 11% performance difference on Gerald's testcase on my setup,
>> > just FYI.
>>
>> If I read this correctly...
>>
>> On Mon, 1 Dec 2003, Diego Novillo wrote:
>> > Unless it's a huge win, I would *really* want to go back to the previous
>> > scheme of having unique SSA numbers across the whole compilation unit.
>>
>> ...you might be able to convince Diego. :-)
>>
>> 11% on PR8361 is quite impressive an improvement!
>
>I'd want to know where that 11% came from, it sounds like one (or more)
>of the optimizations are doing something pretty inefficient and ought to
>be looked at first. Just reducing the number of SSA_NAME ought not have
>that significant an effect if everyone is being reasonably intelligent
>about how they do things.
>
>Its definately worth investigating.
Well, I'm not sure I believe the 11% number to start with. If it is
believable, then like you, I'd think we've got an optimizer that is
doing something dumb.
Jeff