[llvm] [IR][LangRef] Add partial reduction add intrinsic (PR #94499)

[Paul Walker via llvm-commits]

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@@ -2635,6 +2635,12 @@ def int_vector_deinterleave2 : DefaultAttrsIntrinsic<[LLVMHalfElementsVectorType
                                                      [llvm_anyvector_ty],
                                                      [IntrNoMem]>;
 
+//===-------------- Intrinsics to perform partial reduction ---------------===//
+
+def int_experimental_vector_partial_reduce_add : DefaultAttrsIntrinsic<[LLVMMatchType<0>],
+                                                                       [llvm_anyvector_ty, llvm_anyvector_ty],
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paulwalker-arm wrote:

Given this is an experimental intrinsic is it worth implementing that plumbing?

Also, the matcher classes typically exist to allow for fewer explicit types when creating a call, which in this instance is not possible because both vector lengths are unknown (or to put another way, there's no 1-1 link between them).

Personally I think there verifier route is better, plus it allow for a more user friendly error message.

https://github.com/llvm/llvm-project/pull/94499