Bug 104905 - SpvOpFOrdEqual doesn't return correct results for NaNs
Summary: SpvOpFOrdEqual doesn't return correct results for NaNs
Status: RESOLVED FIXED
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/Vulkan/radeon (show other bugs)
Version: git
Hardware: All All
: medium normal
Assignee: mesa-dev
QA Contact: mesa-dev
URL:
Whiteboard:
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Depends on:
Blocks:
 
Reported: 2018-02-01 15:02 UTC by Józef Kucia
Modified: 2018-02-26 14:43 UTC (History)
0 users

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Description Józef Kucia 2018-02-01 15:02:12 UTC 
SpvOpFOrdEqual doesn't seem to perform ordered comparison, e.g. NaN and 1.0 gives true. I expect this to also be a problem for other ordered comparison SPIR-V opcodes.

Mesa SPIR-V to NIR translator inserts additional nir_feq instructions in order to detect NaNs, but those instructions are probably optimized out by LLVM.

The problem can be reproduced by running VKD3D tests: https://source.winehq.org/git/vkd3d.git/blob/HEAD:/tests/d3d12.c#l6640

I can write a standalone test case, if needed.
Comment 1 Samuel Pitoiset 2018-02-09 09:09:22 UTC 
Hi Jozef,

Yeah, would be nice to have a standalone case.
Comment 2 Samuel Pitoiset 2018-02-26 13:10:26 UTC 
This should fix the issue https://cgit.freedesktop.org/mesa/mesa/commit/?id=e05507a427b79e481eb8e45d7aa3c9b4b78376bf 

Can you confirm and close the bug, please?

Thanks!
Comment 3 Józef Kucia 2018-02-26 14:43:08 UTC 
e05507a427b79e481eb8e45d7aa3c9b4b78376bf fixes the issue. Thanks!

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