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OpenCL

kvalme
Journeyman III

OpenCL compiler bug with big switches

Hi.

Recently I found an issue with AMD OpenCL compiler.

I got OpenCL code that generated on CPU and results in big switch-case construction (about 4k case).

Attempt to compile such kernel with AMD compiler leads to :

  • RGA 2.0/Vega in-driver compiler (latest on win10)
    • Compiler eats 6Gb of host ram and unable to compile in 3 hours
  • RGA 1.4/Vega in-driver compiler(amdgpu-pro-18.20-579836 kubuntu 18.04)
    • Compiler eats 24Gb of host ram and that crashes with not enought memory

Reducing "case" count to 2k results in successful kernel compilation.

Here is kernel source:

https://drive.google.com/file/d/1SxuXw5KTqWMBWAJWf9jJgyyeeWa5V_Xu/view?usp=sharing

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dipak
Staff
Staff

Re: OpenCL compiler bug with big switches

Hi Denis,

Thanks for reporting it. We will verify and get back to you shortly.

Meanwhile, could you please try with CodeXL and let us know whether you observe the same issue or not?

Regards,

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kvalme
Journeyman III

Re: OpenCL compiler bug with big switches

Hi dipak,

Unfortunately I can't test it in CodeXL for now, since it doesn't work in ubuntu 18.04 (unable to start since ubuntu 18.04 don't have libpng12). I'll try to check it later when I have access to windows system. But I believe it should have same result since CodeXL seems to use RGA..

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kvalme
Journeyman III

Re: OpenCL compiler bug with big switches

Have also checked this kernel on Nvidia card. Works fine, compilation takes 3-5 mins (compiled for 1080)

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dipak
Staff
Staff

Re: OpenCL compiler bug with big switches

Hi Denis,

While testing with CodeXL on Win10, I also observed a huge increase in system memory usage and in my case, the GUI stopped responding after some time and I had to reboot. I'll check it with more recent internal builds and take the action accordingly.

P.S. The same kernel seems building fine for Southern Islands (SI) cards like Tahiti, Pitcairn etc.

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dipak
Staff
Staff

Re: OpenCL compiler bug with big switches

Hi,

It seems the issue is also reproducible with the latest internal builds. I have opened a ticket against the issue. Once there is any update, I'll let you know.

Regards,

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