[llvm] [Intrinsic] Unify IIT_STRUCT{2-9} into ITT_STRUCT to support upto 257 return value (PR #160434)

[Rahul Joshi via llvm-commits]

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@@ -348,14 +341,6 @@ defvar IIT_all_VectorTypes = !filter(iit, IIT_all,
 defvar IIT_RetNumbers = [
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jurahul wrote:

Does IIT_RetNumbers  serve any meaningful purpose after this change? Maybe we can get rid of it as well? 

https://github.com/llvm/llvm-project/pull/160434