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

[David Sherwood via llvm-commits]

================
@@ -19637,6 +19637,59 @@ are undefined.
     }
 
 
+'``llvm.experimental.vector.match.*``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+This is an overloaded intrinsic. Support for specific vector types is target
+dependent.
+
+::
+
+    declare <<n> x i1> @llvm.experimental.vector.match(<<n> x <ty>> %op1, <<n> x <ty>> %op2, <<n> x i1> %mask, i32 <segsize>)
+    declare <vscale x <n> x i1> @llvm.experimental.vector.match(<vscale x <n> x <ty>> %op1, <vscale x <n> x <ty>> %op2, <vscale x <n> x i1> %mask, i32 <segsize>)
+
+Overview:
+"""""""""
+
+Find elements of the first argument matching any elements of the second.
+
+Arguments:
+""""""""""
+
+The first argument is the search vector, the second argument is 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 fourth argument is an immediate that sets the segment
+size for the search window.
----------------
david-arm wrote:

'For the search window' makes sense, but it's a big ambiguous as to whether you're referring to the first or second argument, or both.

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