[llvm] [RISCV][VP] Introduce vp saturating addition/substraction and RISC-V support. (PR #82370)

[Yeting Kuo via llvm-commits]

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@@ -23579,6 +23586,198 @@ Examples:
       %also.r = select <4 x i1> %mask, <4 x i32> %t, <4 x i32> poison
 
 
+.. _int_vp_sadd_sat:
+
+'``llvm.vp.sadd.sat.*``' Intrinsics
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+This is an overloaded intrinsic.
+
+::
+
+      declare <16 x i32>  @llvm.vp.sadd.sat.v16i32 (<16 x i32> <left_op> <16 x i32> <right_op>, <16 x i1> <mask>, i32 <vector_length>)
+      declare <vscale x 4 x i32>  @llvm.vp.sadd.sat.nxv4i32 (<vscale x 4 x i32> <left_op>, <vscale x 4 x i32> <right_op>, <vscale x 4 x i1> <mask>, i32 <vector_length>)
+      declare <256 x i64>  @llvm.vp.sadd.sat.v256i64 (<256 x i64> <left_op>, <256 x i64> <right_op>, <256 x i1> <mask>, i32 <vector_length>)
+
+Overview:
+"""""""""
+
+Predicated signed saturating addition of two vectors of integers.
+
+
+Arguments:
+""""""""""
+
+The first two operand and the result have the same vector of integer type. The
+third operand is the vector mask and has the same number of elements as the
+result vector type. The fourth operand is the explicit vector length of the
+operation.
+
+Semantics:
+""""""""""
+
+The '``llvm.vp.sadd.sat``' intrinsic performs sadd.sat (:ref:`sadd.sat <int_sadd_sat>`) of the first, second,
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yetingk wrote:

Done.

https://github.com/llvm/llvm-project/pull/82370