[Bug fortran/49540] [4.6/4.7 Regression] Memory-hog with large DATA stmt

[adrian.sevcenco at cern dot ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49540

Adrian Sevcenco <adrian.sevcenco at cern dot ch> changed:

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--- Comment #8 from Adrian Sevcenco <adrian.sevcenco at cern dot ch> 2011-06-28 08:59:38 UTC ---
(In reply to comment #7)
> (In reply to comment #6)
> > (In reply to comment #2)
> > > Thus, in some way, the repeat count must come back. One possibility is to
> > > handle the special case /<array_size>*<value>/, which is equivalent to
> > > a scalar initialization. I think that should cover the most common case.
> > 
> > IIRC, as implemented the array constructor is completely unrolled, for each
> > element an entry in the splay tree is generated.
> 
> Yes - at least since dropping the repeat count, which your patch did.
> 
> > One could apply the -fmax-array-constructor=<value> restrictions used e.g. for
> > PARAMETER arrays and do not unroll arrays of size larger than <value> but do it
> > on runtime.
> 
> As written, I think it should be sufficient to support the initialization via a
> scalar. In terms of the trans*.c files that already works:
>   real :: a(3) = 0
> thus, there is no reason why one should be able to set sym->value also for
>   real a(3)
>   data a/3*0/
> 
> That is: If - and only if - one has <repeat count> == size(array), i.e. a
> whole-array initialization, one changes the initialization from:
>   sym->value  =  [ ( <value>, i = 1, <repeat count>) ]
> to
>   sym->value  =  <value>
> 
> That should require some reshoveling in the code, but sounds much cleaner as
> -fmax-array-constructor= tweaking. Additionally, it will generate much faster
> code for "data a/10000000*0.0/" as it gets translated into "static real a =
> {}".

so with regard to the initial submission from 
https://bugzilla.redhat.com/show_bug.cgi?id=716721
(and code from
http://alisoft.cern.ch/viewvc/trunk/TAmpt/AMPT/hijing1.383_ampt.f?view=markup&root=AliRoot)

do you have some specific (and certain) recommendations in order to make this
scientific code to be compiled (alongside with a lot other fortran scientific
code)?
Thanks