6.0.0 crash at high precision mul?

Marc Glisse marc.glisse at inria.fr
Thu Jun 5 12:25:17 UTC 2014

On Thu, 5 Jun 2014, Torbjörn Granlund wrote:

> Marc Glisse <marc.glisse at inria.fr> writes:
>  Yes, better replace 65536 with something smaller in gmp-impl.h.

Note this was meant as a suggestion for the OP, not necessarily a 
proposition for GMP (you already rejected it some years ago).

> That's 65536 bytes, or 8192 limbs on a 64-bit machine.  It is not clear
> to me that this is a too high limit, not even for a system with tiny
> stack size defaults.

Some GMP functions do 10 allocations, can be called recursively, call 
other functions that do allocations, etc. With a 512kB stack (or even 1MB) 
it goes quite quickly...

Is there a measurable performance difference if we divide 65536 by 4?

I think it was Marco who wanted to generalize the use of TMP_ALLOC_LIMBS_2 
recently, that could help as well.

Marc Glisse

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