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

[Graham Hunter 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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huntergr-arm wrote:

I think adding a new matcher class to constrain the second parameter to the restrictions you defined in the langref would be helpful (same element type, width an integer multiple).

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