[clang] [Headers] Add \returns to _rdpid_u32 (PR #70481)

[Paul T Robinson via cfe-commits]

https://github.com/pogo59 created https://github.com/llvm/llvm-project/pull/70481

Our doc tooling complained about this missing directive.

>From a6bcb7b93d3d856a367b40b08a42c641c87217f3 Mon Sep 17 00:00:00 2001
From: Paul Robinson <paul.robinson at sony.com>
Date: Fri, 27 Oct 2023 10:00:00 -0700
Subject: [PATCH] [Headers] Add \returns to _rdpid_u32

---
 clang/lib/Headers/immintrin.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Headers/immintrin.h b/clang/lib/Headers/immintrin.h
index 642602be14e60e6..9bfe2fcdabdb3a5 100644
--- a/clang/lib/Headers/immintrin.h
+++ b/clang/lib/Headers/immintrin.h
@@ -291,11 +291,13 @@
 
 #if !(defined(_MSC_VER) || defined(__SCE__)) || __has_feature(modules) ||      \
     defined(__RDPID__)
-/// Returns the value of the IA32_TSC_AUX MSR (0xc0000103).
+/// Reads the value of the IA32_TSC_AUX MSR (0xc0000103).
 ///
 /// \headerfile <immintrin.h>
 ///
 /// This intrinsic corresponds to the <c> RDPID </c> instruction.
+///
+/// \returns The 32-bit contents of the MSR.
 static __inline__ unsigned int __attribute__((__always_inline__, __nodebug__, __target__("rdpid")))
 _rdpid_u32(void) {
   return __builtin_ia32_rdpid();