Crashes after upgrading to GMP 6.20+

Torbjörn Granlund tg at
Thu Apr 29 20:06:41 UTC 2021

Michael Maroszek <paresy at> writes:

  The code works flawlessly on the Boardwell architecture (and a lot more!).
  The issue arises only on the mentioned Celeron.

As I wrote before, GMP's fat mechanism knows of that processor.  So it
is not a simple oversight on our part which causes the problems you

There can be many explanations.

1. You ae using some sort of virtualiser, and running a fat binary in a
   guest.  That guest is told by the virtualiser that it has a CPU with
   instructions which are actually missing.

2. You have a compiler which by default generates instructions which are
   not supported by the actual processor.  (GMP makes sure not to enable
   such instructions for fat builds, but it doesn't know how to override
   all mechanisms which could control the compiler's defaults.)

Please encrypt, key id 0xC8601622

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