Bump internal copy of half to fix issues on older x86_64 CPUs on Windows

AcademySoftwareFoundation / openvdb

OpenVDB - Sparse volume data structure and tools

http://www.openvdb.org/

Apache License 2.0

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Bump internal copy of half to fix issues on older x86_64 CPUs on Windows #1733

Closed brechtvl closed 10 months ago

brechtvl commented 11 months ago

On some older CPUs without support for the lzcnt instruction, the conversion from half to float was wrong.

See AcademySoftwareFoundation/Imath#358 for more details.

Thanks to Ray Molenkamp for tracking down this bug.

brechtvl commented 11 months ago

For reference, we hit this in Blender when upgrading to the VFX platform 2024, from OpenVDB 10 to 11.

CPU's like Sandy Bridge and Ivy Bridge that are affected by this are relatively old, but still support the minimum requirement of SSE 4.2 used by Blender, Maya and Houdini.