Compiler writer questions
Bil Kleb
This request just went out to our team:
itemize what we would want out of a compiler-writer visit
I can only think of two related questions:
What areas of the F95 cause the most pain w.r.t. optimization?
What can we do as code developers to "help" the compiler?
Other ideas?
Thanks,
--
Bil Kleb
http://fun3d.larc.nasa.gov
John Harper
>Hi,
>
>This request just went out to our team:
>
> itemize what we would want out of a compiler-writer visit
>
>I can only think of two related questions:
>Other ideas?
What areas of the F2003 standard are causing you the most pain to
implement?
When do you think you'll be able to release a full f2003 compiler?
What areas of the F2008 standard do you think will cause you the most
pain to implement?
When do you think you'll be able to release a full f2008 compiler?
-- John Harper, School of Mathematics, Statistics and Computer Science,
Victoria University, PO Box 600, Wellington 6140, New Zealand
e-mail john....@vuw.ac.nz phone (+64)(4)463 6780 fax (+64)(4)463 5045
Beliavsky
> Hi,
>
> This request just went out to our team:
>
> itemize what we would want out of a compiler-writer visit
>
> I can only think of two related questions:
>
> What areas of the F95 cause the most pain w.r.t. optimization?
Same for F2003. I think allocation upon assignment is one "painful"
area, as discussed here recently.
> What can we do as code developers to "help" the compiler?
>
> Other ideas?
When will you have a Fortran 2003 compiler?
If a compiler offers free updates for the next N months, will they
have a Fortran 2003 compiler in N months?
What is your timeline on adding specific features? If g95 has a
Fortran 2003 feature, I'll be more likely to employ it if Intel
Fortran has it now or will have it in a few months.
William Clodius
> Hi,
>
> This request just went out to our team:
>
> itemize what we would want out of a compiler-writer visit
>
> I can only think of two related questions:
>
> What areas of the F95 cause the most pain w.r.t. optimization?
>
> What can we do as code developers to "help" the compiler?
> <snip>
Others have suggested asking about F2003. I would suggest asking about
detecting more fundamental problems with the source code, i.e., illegal
modifiable aliasing, array out of bound checks, memory leaks, etc. For
optimization/memory management you might ask about stack versus heap
alloction.
Thomas Koenig
> What can we do as code developers to "help" the compiler?
If you think something is broken, submit bug reports through
the appropriate channels, with self-contained, preferably small
test cases. Indicate what you expected of the compiler, and what
happened instead.
If the compiler in question happens to be a "bazaar" - style
open-source project, you can also volunteer to fix bugs :-)
Bil Kleb
> On 2008-05-06, Bil Kleb <Bil....@NASA.gov> wrote:
>
>> What can we do as code developers to "help" the compiler?
>
> If you think something is broken, submit bug reports through
I feel you've taken this second, related question out of context
with the first:
What areas of the F95 cause the most pain w.r.t. optimization?
I meant "help" in terms of what coding conventions (e.g.,
using INTENT, using TARGET, unrolling array syntax, unrolling derived
types in calling arguments, and so forth) should we, as code writers,
adopt to "help" the compiler more easily produce optimized code.
Sorry about the ambiguity,
--
http://twitter.com/bil_kleb
Greg Lindahl
Thomas Koenig <tko...@netcologne.de> wrote:
>If you think something is broken, submit bug reports through
>the appropriate channels, with self-contained, preferably small
>test cases.
In many cases, a self-contained small test case is not necessary, and
generating the self-contained small test case can take a long
time. Telling users that you prefer one can cause many bugs to go
unreported.
You can look in the PathScale manuals for some text suggesting bug
types for which finding a small example isn't worth the end-users
effort.
>If the compiler in question happens to be a "bazaar" - style
>open-source project, you can also volunteer to fix bugs :-)
I've submitted patches to "cathedral" style open source projects,
and they were used.
-- greg
fj
> In article <fvq52g$6j...@aioe.org>, Bil Kleb <Bil.K...@NASA.gov> wrote:
>
> >Hi,
>
> >This request just went out to our team:
>
> > itemize what we would want out of a compiler-writer visit
>
> >I can only think of two related questions:
> ...
> >Other ideas?
>
> What areas of the F2003 standard are causing you the most pain to
> implement?
>
> When do you think you'll be able to release a full f2003 compiler?
>
> What areas of the F2008 standard do you think will cause you the most
> pain to implement?
>
> When do you think you'll be able to release a full f2008 compiler?
>
> -- John Harper, School of Mathematics, Statistics and Computer Science,
> Victoria University, PO Box 600, Wellington 6140, New Zealand
All these questions are interesting (especially the release of F2003
and F2008 compilers) but I would prefer the answers :-(
Jim Xia
>
> What can we do as code developers to "help" the compiler?
Don't write illegal code probably is the most important thing to do to
"help" the optimizer. One very common error is procedure calls like
"proc(a, a)", where both dummy arguments can alter its value. This
screws up optimizer in aliasing. Another common problem is common
block declaration mismatch in different scoping units because they may
end up with different alignments. Many other small things like try to
avoid equivalence. One piece of suggestion you may hear from the
optimizer is, don't try to optimize your code by yourself, let the
optimizer do its job :-)
Cheers,