[clang] [llvm] [AMDGPU] Adding the amdgpu-num-work-groups function attribute (PR #79035)

[Erich Keane via cfe-commits]

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@@ -2705,6 +2705,33 @@ An error will be given if:
   }];
 }
 
+def AMDGPUMaxNumWorkGroupsDocs : Documentation {
+  let Category = DocCatAMDGPUAttributes;
+  let Content = [{
+This attribute specifies the max number of work groups when the kernel
+is dispatched.
+
+Clang supports the
+``__attribute__((amdgpu_max_num_work_groups(<x>, <y>, <z>)))`` or
+``[[clang::amdgpu_max_num_work_groups(<x>, <y>, <z>)]]`` attribute for the
+AMDGPU target. This attribute may be attached to HIP or OpenCL kernel function
+definitions and is an optimization hint.
+
+``<x>`` parameter specifies the maximum number of work groups in the x dimension.
+Similarly ``<y>`` and ``<z>`` are for the y and z dimensions respectively.
+Each of the three numbers must be >=1. The attribute is ignored if any of the
----------------
erichkeane wrote:

I don't think 'ignored' is the right semantics here: that should diagnose.

https://github.com/llvm/llvm-project/pull/79035