[Mesa-dev] [Bug 108856] floating-point-exceptions in gallium/auxiliary/tgsi/ functions

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108856

            Bug ID: 108856
           Summary: floating-point-exceptions in gallium/auxiliary/tgsi/
                    functions
           Product: Mesa
           Version: 18.2
          Hardware: Other
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Drivers/OSMesa
          Assignee: mesa-dev at lists.freedesktop.org
          Reporter: popinet at basilisk.fr
        QA Contact: mesa-dev at lists.freedesktop.org

Calling the gallium osmesa implementation generates multiple floating-point
exceptions.

For example the src/gallium/auxiliary/tgsi/tgsi_exec.c:554, micro_rsq()
function contains the code:

   dst->f[0] = 1.0f / sqrtf(src->f[0]);

and is sometimes called with src->f[0] == 0.

This is an important issue for (scientific) codes which typically turn
floating-point-exceptions on.

A workaround is to turn FPE off before each GL/OSmesa call and turn them back
on after.

Note that the non-gallium OSMesa implementation does not have this issue.

-- 
You are receiving this mail because:
You are the assignee for the bug.
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20181125/1c152893/attachment-0001.html>