[llvm] [Offload] Add `ol_dimensions_t` (PR #143901)

[Joseph Huber via llvm-commits]

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@@ -148,6 +148,16 @@ def : Struct {
   ];
 }
 
+def : Struct {
+  let name = "ol_dimensions_t";
+  let desc = "A three element vector";
+  let members = [
+    StructMember<"size_t", "x", "X">,
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jhuber6 wrote:

These should probably be u32, that's how it is in the launch args and the CUDA structs.

https://github.com/llvm/llvm-project/pull/143901