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Re: Implement stack arrays even for unknown sizes

From: dominiq at lps dot ens dot fr (Dominique Dhumieres)
To: paul dot richard dot thomas at gmail dot com, matz at suse dot de
Cc: gcc-patches at gcc dot gnu dot org, fortran at gcc dot gnu dot org, dominiq at lps dot ens dot fr
Date: Tue, 12 Apr 2011 08:35:16 +0200
Subject: Re: Implement stack arrays even for unknown sizes
References: <20110409100809.BF9CD3BE18@mailhost.lps.ens.fr> <BANLkTikwa8es+FxG2ThwWMo4MFGWVeddvg@mail.gmail.com> <Pine.LNX.4.64.1104111800010.1989@wotan.suse.de> <BANLkTi=jh8pGdaKLMFhJyEEU+_bnJ1VusQ@mail.gmail.com>

> The resulting speed up for nf.f90 is rather remarkable.  What specific
> feature of the fortran leads to a 30=>15s ?

I think it is the automatic array in the subroutine trisolve. Note that the 
speedup is rather 27->19s and may be darwin specific (slow malloc).

Note also that -fstack-arrays prevents some optimizations on
fatigue: 4.7->7s. This may be related to pr45810.

Dominique

Follow-Ups:
- Re: Implement stack arrays even for unknown sizes
  - From: Paul Richard Thomas
- Re: Implement stack arrays even for unknown sizes
  - From: Michael Matz

References:
- Re: Implement stack arrays even for unknown sizes
  - From: Dominique Dhumieres
- Re: Implement stack arrays even for unknown sizes
  - From: Paul Richard Thomas
- Re: Implement stack arrays even for unknown sizes
  - From: Michael Matz
- Re: Implement stack arrays even for unknown sizes
  - From: Paul Richard Thomas

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