[clang] [llvm] [clang][SPIR-V] Add support for AMDGCN flavoured SPIRV (PR #89796)

[Vyacheslav Levytskyy via cfe-commits]

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@@ -114,15 +118,17 @@ Example:
 
 ``-target spirv64v1.0`` can be used to compile for SPIR-V version 1.0 with 64-bit pointer width.
 
+``-target spirv64-amd-amdhsa`` can be used to compile for AMDGCN flavoured SPIR-V version 1.6 with 64-bit pointer width
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VyacheslavLevytskyy wrote:

I'm not sure how the number of the version 1.6 will be deducted from just `spirv64-amd-amdhsa`.

https://github.com/llvm/llvm-project/pull/89796