bug with ODE numeric code on ARM with LuaJIT2

[Francesco Abbate <francesco.bbt@...>]

Hi Mike, all,

we have made some tests with Lesley to make sure that GSL Shell 2.0
works on ARM. Everything was working out of the box but when
performing the tests we have observed that the code involving numeric
computations like ODE and numeric integration fails when JIT it turned
on (the default). The errors range from segmentation faults to bogus
numeric results.

We have worked to isolate the problem as much as possible and to
reproduce it using a vanilla LuaJIT2 from the git repository.

We have finally managed to make a test suite based on the ODE
integration that show the bug on ARM (Efika MX). Probably this is not
a minimal test case but I guess that it is quite reasonable to be used
to debug the problem.

I'm sending a patch (git format) for LuaJIT2 from the standard
repository. The patch just adds the tests we have developped with
Lesley to reproduce the bug.

The idea is that these tests fails with the standard LuaJIT2 but only
on Efika MX, I don't know about other ARM platforms.

Only the test ode-test-2 fails as far as I know. Please note that
'num.lua' include some spurious declarations: there are needed to
trigger the bug!!

Please let me know if you want the we try to make a more minimal example.

Best regards,
Francesco

Attachment: 0001-GSL-Shell-ODE-test-suite-for-LuaJIT2.patch
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Attachment: 0002-Improve-ODE-test-suite-to-align-with-GSL-Shell-demos.patch
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Attachment: 0003-Add-spurious-declarations-to-trigger-ARM-bug.patch
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