[radv] - Persona 5 in RPCS3 emulator has glitches when using hardware fp16 (LLVM 9)

Submitted by Andrew Sheldon

Assigned to mes..@..op.org

Description

Since RPCS3 added support for native 16-bit float support, Persona 5 is exhibiting graphical glitches when using its Vulkan renderer:

With hardware fp16: https://i.imgur.com/NOyfaN7.jpg

With hardware fp16 disabled (correct rendering): https://i.imgur.com/7oYKdBi.jpg

System: Gentoo AMD64 Mesa git (RADV) LLVM 9 git RPCS3 git Vega 56

Here's a link to the corresponding RPCS3 report: https://github.com/RPCS3/rpcs3/issues/6150

They suggest the problem may be with LLVM code generation. I should note that AMDVLK also has the same bug, which supports this conclusion. LLVM 8 can't be tested since it causes a black screen with RPCS3 (https://bugs.freedesktop.org/show_bug.cgi?id=110970).

Also of note, bug doesn't occur with an RX-550 (on RADV or AMDVLK) and the bug doesn't occur at all on Windows. So it looks to be a Vega specific bug, and only on Linux.

Version: git

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