Bug#1068174: yosys: Please package the latest upstream release

[Scott Ashcroft]

On Tue, 2025-03-18 at 01:32 +0100, Daniel Gröber wrote:
> We've seen FST problems due to i386 floating point weirdness before (rounding, 80bit>64bit conversion IIRC). Might just be something like that again.

Looks like you are spot on.
The i386 and amd64 versions write identical FST files.
When the i386 version tries to read back the file it has just written
it fails trying to do an endian check on doubles.

Commenting out the check at libs/fst/fstapi.cc:4727 makes the FST tests
pass.
Maybe we need to replace it with a test which says it is within a
delta.

The same code is used in gtkwave and iverilog so it looks like nobody
cares about i386.

> Could drop 32bit or just skip tests there. I may have a quick look tomorrow and drop if its too annoying.

If we just skip the tests then the i386 version won't be able to use
FST files at all.

Assuming we fix that up somehow then a bunch of other tests fail on all
32-bit archs.

simple/string_format
simple_abc9/string_format

both make iverilog try to malloc huge amounts of memory. I can't tell
if the problem is on the yosys or iverilog side of things.

The tests in cxxrtl fail too. No floating point so I guess just a size
of int/pointer mismatch somewhere.

I suspect just dropping 32-bit support is going to be easiest way
forward as the upstreams of major bits of the FPGA workflow are broken.


Cheers,
Scott