[clang] [AArch64] Update __gcsss intrinsic to match revised ACLE specification (PR #136850)

[via cfe-commits]

https://github.com/sivan-shani updated https://github.com/llvm/llvm-project/pull/136850

>From a3cc71ef731e08d9e0963db767e190a231f75260 Mon Sep 17 00:00:00 2001
From: Sivan Shani <sivan.shani at arm.com>
Date: Wed, 23 Apr 2025 12:39:05 +0100
Subject: [PATCH 1/2] [AArch64] Update __gcsss intrinsic to match revised ACLE
 specification

The original __gcsss intrinsic was implemented based on:
https://github.com/ARM-software/acle/pull/260
with the signature: const void *__gcsss(const void *)

Per the updated specification in:
https://github.com/ARM-software/acle/pull/364
both const qualifiers have been removed. This commit updates the signature accordingly to:
void *__gcsss(void *)

This aligns the implementation with the latest ACLE definition.
---
 clang/include/clang/Basic/BuiltinsAArch64.def | 2 +-
 clang/lib/Headers/arm_acle.h                  | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.def b/clang/include/clang/Basic/BuiltinsAArch64.def
index 19fa7215b5000..8867a9fe09fb9 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.def
+++ b/clang/include/clang/Basic/BuiltinsAArch64.def
@@ -137,7 +137,7 @@ TARGET_BUILTIN(__builtin_arm_st64bv0, "WUiv*WUiC*", "n", "ls64")
 
 // Armv9.3-A Guarded Control Stack
 TARGET_BUILTIN(__builtin_arm_gcspopm, "WUiWUi", "n", "gcs")
-TARGET_BUILTIN(__builtin_arm_gcsss, "vC*vC*", "n", "gcs")
+TARGET_BUILTIN(__builtin_arm_gcsss, "v*v*", "n", "gcs")
 
 TARGET_HEADER_BUILTIN(_BitScanForward, "UcUNi*UNi", "nh", INTRIN_H, ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_BitScanReverse, "UcUNi*UNi", "nh", INTRIN_H, ALL_MS_LANGUAGES, "")
diff --git a/clang/lib/Headers/arm_acle.h b/clang/lib/Headers/arm_acle.h
index 89db5dc2d7aaa..5cfa3d023a7d5 100644
--- a/clang/lib/Headers/arm_acle.h
+++ b/clang/lib/Headers/arm_acle.h
@@ -841,8 +841,9 @@ __gcspopm() {
   return __builtin_arm_gcspopm(0);
 }
 
-static __inline__ const void * __attribute__((__always_inline__, __nodebug__, target("gcs")))
-__gcsss(const void *__stack) {
+static __inline__ void *__attribute__((__always_inline__, __nodebug__,
+                                       target("gcs")))
+__gcsss(void *__stack) {
   return __builtin_arm_gcsss(__stack);
 }
 #endif

>From dfbb1c22204032b359a5fc0c14853300b0b0e330 Mon Sep 17 00:00:00 2001
From: Sivan Shani <sivan.shani at arm.com>
Date: Wed, 23 Apr 2025 17:18:21 +0100
Subject: [PATCH 2/2] update test file (remove const)

---
 clang/test/CodeGen/AArch64/gcs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clang/test/CodeGen/AArch64/gcs.c b/clang/test/CodeGen/AArch64/gcs.c
index 767b1b8bfaf2d..64785be2af623 100644
--- a/clang/test/CodeGen/AArch64/gcs.c
+++ b/clang/test/CodeGen/AArch64/gcs.c
@@ -1,4 +1,4 @@
-// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 2
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --clang-args ['-target-feature', '+gcs'] --version 2
 // RUN: %clang_cc1 -triple aarch64-eabi -target-feature +gcs -emit-llvm %s -o - | FileCheck %s
 
 #include <arm_acle.h>
@@ -51,6 +51,6 @@ uint64_t test_gcspopm() {
 // CHECK-NEXT:    [[TMP2:%.*]] = call ptr @llvm.aarch64.gcsss(ptr [[TMP1]])
 // CHECK-NEXT:    ret ptr [[TMP2]]
 //
-const void *test_gcsss(const void *p) {
+void *test_gcsss(void *p) {
   return __gcsss(p);
 }