[llvm] [AArch64] Add @llvm.experimental.vector.match (PR #101974)

[Paul Walker via llvm-commits]

================
@@ -20043,6 +20043,47 @@ are undefined.
     }
 
 
+'``llvm.experimental.vector.match.*``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+This is an overloaded intrinsic.
+
+::
+
+    declare <<n> x i1> @llvm.experimental.vector.match(<<n> x <ty>> %op1, <<m> x <ty>> %op2, <<n> x i1> %mask)
+    declare <vscale x <n> x i1> @llvm.experimental.vector.match(<vscale x <n> x <ty>> %op1, <<m> x <ty>> %op2, <vscale x <n> x i1> %mask)
+
+Overview:
+"""""""""
+
+Find active elements of the first argument matching any elements of the second.
+
+Arguments:
+""""""""""
+
+The first argument is the search vector, the second argument the vector of
+elements we are searching for (i.e. for which we consider a match successful),
+and the third argument is a mask that controls which elements of the first
+argument are active. The first two arguments must be vectors of matching
+integer element types. The first and third arguments and the result type must
+have matching element counts (fixed or scalable). The second argument must be a
+fixed vector, but its length may be different from the remaining arguments.
+
+Semantics:
+""""""""""
+
+The '``llvm.experimental.vector.match``' intrinsic compares each active element
+in the first argument against the elements of the second argument, placing
+``1`` in the corresponding element of the output vector if any equality
+comparison is successful, and ``0`` otherwise. Inactive elements in the mask
+are set to ``0`` in the output.
+
+The second argument needs to be a fixed-length vector with the same element
+type as the first argument.
----------------
paulwalker-arm wrote:

This can be removed because it's already discussed in the `Arguments` section.

https://github.com/llvm/llvm-project/pull/101974