* Scalar Replacement
@ 2004-09-22 15:51 Canqun Yang
2004-09-22 16:15 ` Steven Bosscher
2004-09-22 16:17 ` Fortran array format [Was: Scalar Replacement] Paul Brook
0 siblings, 2 replies; 3+ messages in thread
From: Canqun Yang @ 2004-09-22 15:51 UTC (permalink / raw)
To: fortran, gcc
Hi, all
I'm going to implement scalar replacement optimization
on trees of GCC backend. Does anyone plan to do the
same work? If so, please let me know.
By now, the problem I encountered is the
representation for array references of Fortran 95. As
Gnu Fortran 95 frontend converts multi-dimensions
arrays to one-dimension array references, it is hard
to recover the number of dimensions and the index of
each dimension for array references. This makes the
dependence relation analysis failed to perform on tree
loops.
Is there any way to recover those information without
modifying the Fortran 95 frontend?
Or, if not. How to modify the frontend to satisify
this?
I'm looking forward for suggestions.
Canqun Yang
Creative Compiler Research Group.
National University of Defense Technology, P. R. China.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Scalar Replacement
2004-09-22 15:51 Scalar Replacement Canqun Yang
@ 2004-09-22 16:15 ` Steven Bosscher
2004-09-22 16:17 ` Fortran array format [Was: Scalar Replacement] Paul Brook
1 sibling, 0 replies; 3+ messages in thread
From: Steven Bosscher @ 2004-09-22 16:15 UTC (permalink / raw)
To: Canqun Yang; +Cc: fortran, gcc
On Sep 22, 2004 05:03 PM, Canqun Yang <canqun@nudt.edu.cn> wrote:
> I'm going to implement scalar replacement optimization
> on trees of GCC backend.
See tree-sra.c.
Gr.
Steven
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Fortran array format [Was: Scalar Replacement]
2004-09-22 15:51 Scalar Replacement Canqun Yang
2004-09-22 16:15 ` Steven Bosscher
@ 2004-09-22 16:17 ` Paul Brook
1 sibling, 0 replies; 3+ messages in thread
From: Paul Brook @ 2004-09-22 16:17 UTC (permalink / raw)
To: fortran, Canqun Yang; +Cc: gcc
On Wednesday 22 September 2004 16:03, Canqun Yang wrote:
> By now, the problem I encountered is the
> representation for array references of Fortran 95. As
> Gnu Fortran 95 frontend converts multi-dimensions
> arrays to one-dimension array references, it is hard
> to recover the number of dimensions and the index of
> each dimension for array references. This makes the
> dependence relation analysis failed to perform on tree
> loops.
>
> Is there any way to recover those information without
> modifying the Fortran 95 frontend?
This sounds like what the linear loop transform and scalar evolutions stuff is
doing.
> Or, if not. How to modify the frontend to satisify
> this?
The fortran frontend should be changed to use the [relatively] new
multiple-argument form of ARRAY_REF.
However before that happens we should check with the tree-ssa and loop
optimization people that the current ARRAY_REF format does provide the
necessary information in an efficient and convenient form.
This was discussed a bit at the last GCC summit, although I don't think we
reached any conclusions. Basically it would be nice to have some way of
communicating fortran array structure to the optimizers. However I don't
think anyone's figured out how best to do this, or how it would fit in with
out existing optimization framework.
Paul
^ permalink raw reply [flat|nested] 3+ messages in thread
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