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Re: alias time explosion
On Tue, 2006-03-21 at 17:30 -0500, Andrew MacLeod wrote:
> On Tue, 2006-03-21 at 10:10 +0100, Richard Guenther wrote:
> > On 3/21/06, Andrew MacLeod <email@example.com> wrote:
> > > On Mon, 2006-03-20 at 18:55 -0500, Andrew Pinski wrote:
> > > > On Mar 20, 2006, at 5:18 PM, Andrew MacLeod wrote:
> > >
> > > It looks like sometime between 10/30 and 01/23 alias analysis got out of
> > > hand. Odd it hasn't been noted before.
> > Can you do a comparison to 4.1.0 and file a PR with the testcase please?
> I will do so in a day or so when I get a chance. until then:
> I seem to have narrowed it down to this patch:
That's quite a while ago :).
> Dan, this appear to *not* be compile time neutral:
> Timings on this patch show that it is not faster or slower than
> what we
> do now (even with the removal of the call clobbering patch). This is
> true even on fortran tests i had that clobber a lot of stuff.
> running cpgram.ii shows a regression:
> before patch:
> tree alias analysis : 2.49 ( 7%) usr 0.25 ( 5%) sys 6.13 ( 5%) wall 4971 kB ( 1%) ggc
> TOTAL : 36.90 4.72 130.34 467341 kB
> after patch:
> tree alias analysis : 59.00 (63%) usr 0.40 ( 7%) sys 70.43 (36%) wall 4957 kB ( 1%) ggc
> TOTAL : 94.13 5.43 193.85 468339 kB
> on a 386 linux machine bootstrapped with checking disabled.
Can you send me cpgram.ii, so i can look into it?
i will note the patch is pretty much required for correctness. We were
getting seriously wrong answers before in some cases.