[clang] [llvm] [SPIRV] GPU intrinsics (PR #131190)

[Michal Paszkowski via llvm-commits]

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@@ -0,0 +1,501 @@
+//===- LowerGPUIntrinsic.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Lower the llvm.gpu intrinsics to target specific code sequences.
+// Can be called from clang if building for a specific GPU or from the backend
+// as part of a SPIRV lowering pipeline. Initial pass can lower to amdgcn or
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michalpaszkowski wrote:

I don't understand how this pass fits into the SPIR-V lowering pipeline. Is this confusing [SPIR and SPIR-V](https://en.wikipedia.org/wiki/Standard_Portable_Intermediate_Representation)? SPIR being the format based on LLVM IR (although on an old version of LLVM 3.4)? SPIR-V being a custom [Khronos-defined format](https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html).

[While SPIR-V easily maps to LLVM IR](https://github.com/KhronosGroup/SPIRV-LLVM-Translator/blob/main/docs/SPIRVRepresentationInLLVM.rst), it is far from being a standardized mapping and the actual translation is usually handled by either [SPIRV-LLVM-Translator](https://github.com/KhronosGroup/SPIRV-LLVM-Translator) or the in-tree SPIR-V backend.

Could you please comment on how this pass and the changes would fit into the current SPIR-V code generation flow through the SPIR-V backend?

https://github.com/llvm/llvm-project/pull/131190