[llvm] [RISCV][doc] Document profiles in RISCVUsage (PR #98326)

[Alex Bradbury via llvm-commits]

https://github.com/asb created https://github.com/llvm/llvm-project/pull/98326

Just like we do for extensions, list those which are supported and those that can be enabled with additional flags.

>From d7044476eef23596df90c025872194bd7c7c67fe Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Wed, 10 Jul 2024 15:10:22 +0100
Subject: [PATCH] [RISCV][doc] Document profiles in RISCVUsage

Just like we do for extensions, list those which are supported and those
that can be enabled with additional flags.
---
 llvm/docs/RISCVUsage.rst | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index 41b22020670d8..a78e57cf9621c 100644
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -70,6 +70,30 @@ To specify the target triple:
 To select an E variant ISA (e.g. RV32E instead of RV32I), use the base
 architecture string (e.g. ``riscv32``) with the extension ``e``.
 
+Profiles
+========
+
+Supported profile names can be passed using ``-march`` instead of a standard
+ISA naming string. Currently supported profiles:
+
+* ``rvi20u32``
+* ``rvi20u64``
+* ``rva20u64``
+* ``rva20s64``
+* ``rva22u64``
+* ``rva22s64``
+
+
+Profiles that are not yet ratified cannot be used unless
+``-menable-experimental-extensions`` (or equivalent for other tools) is
+specified. This applies to the following profiles:
+
+* ``rva23u64``
+* ``rva23s64``
+* ``rvb23u64``
+* ``rvb23s64``
+* ``rvm23u32``
+
 .. _riscv-extensions:
 
 Extensions