[clang] [CIR][CUDA] Shadow variables, internalize device side variables, lower poison attribute (PR #190087)

[Zaky Hermawan via cfe-commits]

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@@ -37,6 +37,24 @@ def CIR_CUDAKernelNameAttr : CIR_Attr<"CUDAKernelName", "cu.kernel_name"> {
   let canHaveIllegalCXXABIType = 0;
 }
 
+def CUDAShadowNameAttr : CIR_Attr<"CUDAShadowName",
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ZakyHermawan wrote:

Make sense, using either attribute fine by me, however if we decide to use `CUDAVarRegistrationInfoAttr`, the registration should be handled by separate PR.

https://github.com/llvm/llvm-project/pull/190087