DPCT1098

Intel® DPC++ Compatibility Tool Developer Guide and Reference

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ID 768918

Date 10/31/2024

Version

Public

Visible to Intel only — GUID: GUID-425DC7E3-C1D3-4A23-8DF7-FFD72611AAF3

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DPCT1098

Message

The <expression text> expression is used instead of the <function name> call. These two expressions do not provide the exact same functionality. Check the generated code for potential precision and/or performance issues.

Detailed Help

No exact functional equivalent of the function was found in SYCL* so an expression composed of other functions was used. Code precision and/or performance may not be as expected. Verify the code for correctness and performance.

Suggestions to Fix

Verify the code for correctness and performance.

For example, this original CUDA* code:

__device__ void device(float *f) {
  float a = __ldg(f);
}

results in the following migrated SYCL code:

void device(float *f) {
  /*
  DPCT1098:0: The '*' expression is used instead of the __ldg call. These two
  expressions do not provide the exact same functionality. Check the generated
  code for potential precision and/or performance issues.
  */
  float a = *f;
}

which is rewritten to:

void device(float *f) {
#if defined(__NVPTX__) && defined(__SYCL_DEVICE_ONLY__)
  float a = sycl::ext::oneapi::experimental::cuda::ldg(f);
#else
  float a = *f;
#endif
}

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Intel® DPC++ Compatibility Tool Developer Guide and Reference

DPCT1098

Message

Detailed Help

Suggestions to Fix