[llvm] [VP][RISCV] Introduce vp.splat and RISC-V. (PR #98731)

[Michael Maitland via llvm-commits]

================
@@ -22841,6 +22841,53 @@ Examples:
  llvm.experimental.vp.splice(<A,B,C,D>, <E,F,G,H>, -2, 3, 2); ==> <B, C, poison, poison> trailing elements
 
 
+.. _int_experimental_vp_splat:
+
+
+'``llvm.experimental.vp.splat``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+This is an overloaded intrinsic.
+
+::
+
+      declare <2 x double> @llvm.experimental.vp.splat.v2f64(double %scalar, <2 x i1> %mask, i32 %evl)
+      declare <vscale x 4 x i32> @llvm.experimental.vp.splat.nxv4i32(i32 %scalar, <vscale x 4 x i1> %mask, i32 %evl)
+
+Overview:
+"""""""""
+
+The '``llvm.experimental.vp.splat.*``' intrinsic is to create a predicated splat
+with specific effective vector length.
+
+Arguments:
+""""""""""
+
+The result is a vector and it is a splat of the first scalar argument. The
+second argument ``mask`` is a vector mask and has the same number of elements as
+the result. The third argument is the explicit vector length of the operation.
----------------
michaelmaitland wrote:

Are there any requirements on the value of `%evl`?

https://github.com/llvm/llvm-project/pull/98731