[clang] [llvm] [aarch64] Add more MSVC intrinsics (atomic part) (PR #194635)

Adhemerval Zanella via cfe-commits cfe-commits at lists.llvm.org
Sat Jun 6 04:52:43 PDT 2026


https://github.com/zatrazz updated https://github.com/llvm/llvm-project/pull/194635

>From 564eefcbaafbea6d8edbfb8f6793230f52a53df7 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Mon, 13 Apr 2026 16:04:27 -0300
Subject: [PATCH 01/26] [aarch64] Add support for the __ldar{8|16|32|64} MS
 intrinsics (#121689)

Adds support for the following MSVC intrinsics:

* `__ldar8`  - maps to LDARB
* `__ldar16` - maps to LDARH
* `__ldar32` - maps to LDAR
* `__ldar64` - maps to LDAR

The emit is done using SeqCst atomic operations because wth RCPC enabled
the AArch64 backend lower acquire loads to LDARP* instead of LDAR*.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  7 ++++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 17 ++++++++++
 clang/lib/Headers/arm64intr.h                 | 13 ++++++++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 32 +++++++++++++++++++
 4 files changed, 69 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 15257f3db5b41..45ba96d014328 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -409,3 +409,10 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES", Header = "intrin.h" in {
 	def __hlt : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int, ...)">;
 }
+
+let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES", Header = "intrin.h" in {
+	def __ldar8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char const volatile *)">;
+	def __ldar16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
+	def __ldar32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
+	def __ldar64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile*)">;
+}
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index ece8ff21561cf..c40ec9a866691 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5327,6 +5327,23 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return ConstantInt::get(Builder.getInt32Ty(), 0);
   }
 
+  if (BuiltinID == AArch64::BI__ldar8 || BuiltinID == AArch64::BI__ldar16 ||
+      BuiltinID == AArch64::BI__ldar32 || BuiltinID == AArch64::BI__ldar64) {
+    Value *Ptr = EmitScalarExpr(E->getArg(0));
+    QualType ElTy = E->getArg(0)->getType()->getPointeeType();
+    CharUnits LoadSize = CGM.getContext().getTypeSizeInChars(ElTy);
+    llvm::Type *ITy =
+        llvm::IntegerType::get(getLLVMContext(), LoadSize.getQuantity() * 8);
+    llvm::LoadInst *Load = Builder.CreateAlignedLoad(ITy, Ptr, LoadSize);
+    // We need SeqCst instead of Acquire because with RCPC enabled the AArch64
+    // lowers Acquire loads to LDARP* instead of LDAR*.  The SeqCst has not RCPC
+    // override and always maps to LDAR*.  This is the same apprach used by
+    // __iso_volatile_load (which uses Monotonic plus volatile for plain ldr).
+    Load->setAtomic(llvm::AtomicOrdering::SequentiallyConsistent);
+    Load->setVolatile(true);
+    return Load;
+  }
+
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
         Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)),
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 53a3d57a6e9d1..8eb36b5624ddb 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -41,5 +41,18 @@ typedef enum
   _ARM64_BARRIER_OSHLD = 0x1
 } _ARM64INTR_BARRIER_TYPE;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+unsigned __int8 __ldar8(const volatile unsigned __int8 *);
+unsigned __int16 __ldar16(const volatile unsigned __int16 *);
+unsigned __int32 __ldar32(const volatile unsigned __int32 *);
+unsigned __int64 __ldar64(const volatile unsigned __int64 *);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ARM64INTR_H */
 #endif /* _MSC_VER */
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index e6a415a0d8805..c1873906808b8 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -668,6 +668,38 @@ void check__prefetch2(void *arg1) {
 // CHECK-LINUX: error: call to undeclared function '__prefetch2'
 
 
+unsigned char check__ldar8(unsigned char volatile *p) {
+  return __ldar8(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__ldar8(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = load atomic volatile i8, ptr %{{.*}} seq_cst, align 1
+// CHECK-MSCOMPAT:       ret i8 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldar8'
+
+unsigned short check__ldar16(unsigned short volatile *p) {
+  return __ldar16(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @check__ldar16(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = load atomic volatile i16, ptr %{{.*}} seq_cst, align 2
+// CHECK-MSCOMPAT:       ret i16 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldar16'
+
+unsigned int check__ldar32(unsigned int volatile *p) {
+  return __ldar32(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @check__ldar32(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = load atomic volatile i32, ptr %{{.*}} seq_cst, align 4
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldar32'
+
+unsigned long long int  check__ldar64(unsigned long long int volatile *p) {
+  return __ldar64(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @check__ldar64(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = load atomic volatile i64, ptr %{{.*}} seq_cst, align 8
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldar64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 308e953e9c48c464b65d975a3b9648b4dc98357c Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Wed, 15 Apr 2026 09:43:49 -0300
Subject: [PATCH 02/26] [aarch64] Add support for the __stlr{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__stlr8`  - maps to STLRB.
* `__stlr16` - maps to STLRH.
* `__stlr32` - maps to STLR.
* `__stlr64` - maps to STLR.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 12 +++++
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 44 +++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 45ba96d014328..dd6d4e02c80e2 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -415,4 +415,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __ldar16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
 	def __ldar32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
 	def __ldar64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile*)">;
+	def __stlr8  : AArch64NoPrefixTargetLibBuiltin<"void (unsigned char volatile *, unsigned char)">;
+	def __stlr16 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned short volatile *, unsigned short)">;
+	def __stlr32 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned int volatile *, unsigned int)">;
+	def __stlr64 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index c40ec9a866691..457a1d38ff1a2 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5344,6 +5344,18 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Load;
   }
 
+  if (BuiltinID == AArch64::BI__stlr8 || BuiltinID == AArch64::BI__stlr16 ||
+      BuiltinID == AArch64::BI__stlr32 || BuiltinID == AArch64::BI__stlr64) {
+    Value *Ptr = EmitScalarExpr(E->getArg(0));
+    Value *Val = EmitScalarExpr(E->getArg(1));
+    QualType ElTy = E->getArg(0)->getType()->getPointeeType();
+    CharUnits StoreSize = CGM.getContext().getTypeSizeInChars(ElTy);
+    llvm::StoreInst *Store = Builder.CreateAlignedStore(Val, Ptr, StoreSize);
+    Store->setAtomic(llvm::AtomicOrdering::Release);
+    Store->setVolatile(true);
+    return Store;
+  }
+
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
         Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)),
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 8eb36b5624ddb..950ecd6aa38cc 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -50,6 +50,11 @@ unsigned __int16 __ldar16(const volatile unsigned __int16 *);
 unsigned __int32 __ldar32(const volatile unsigned __int32 *);
 unsigned __int64 __ldar64(const volatile unsigned __int64 *);
 
+void __stlr8(unsigned __int8 volatile *, unsigned __int8);
+void __stlr16(unsigned __int16 volatile *, unsigned __int16);
+void __stlr32(unsigned __int32 volatile *, unsigned __int32);
+void __stlr64(unsigned __int64 volatile *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index c1873906808b8..2698a35f0c5aa 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -700,6 +700,50 @@ unsigned long long int  check__ldar64(unsigned long long int volatile *p) {
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__ldar64'
 
+void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
+{
+  __stlr8 (p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}void @test__stlr8(ptr{{.*}}%p, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[DEST:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[VALUE:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       store atomic volatile i8 %[[VALUE]], ptr %[[DEST]] release, align 1
+// CHECK-MSCOMPAT:       ret void
+// CHECK-LINUX: error: call to undeclared function '__stlr8'
+
+void test__stlr16(unsigned __int16 volatile *p, unsigned __int16 v)
+{
+  __stlr16 (p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}void @test__stlr16(ptr{{.*}}%p, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[DEST:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[VALUE:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       store atomic volatile i16 %[[VALUE]], ptr %[[DEST]] release, align 2
+// CHECK-MSCOMPAT:       ret void
+// CHECK-LINUX: error: call to undeclared function '__stlr16'
+
+void test__stlr32(unsigned __int32 volatile *p, unsigned __int32 v)
+{
+  __stlr32(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}void @test__stlr32(ptr{{.*}}%p, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[DEST:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[VALUE:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       store atomic volatile i32 %[[VALUE]], ptr %[[DEST]] release, align 4
+// CHECK-MSCOMPAT:       ret void
+// CHECK-LINUX: error: call to undeclared function '__stlr32'
+
+void test__stlr64(unsigned __int64 volatile *p, unsigned __int64 v)
+{
+  __stlr64(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}void @test__stlr64(ptr{{.*}}%p, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[DEST:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[VALUE:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       store atomic volatile i64 %[[VALUE]], ptr %[[DEST]] release, align 8
+// CHECK-MSCOMPAT:       ret void
+// CHECK-LINUX: error: call to undeclared function '__stlr64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 6451ad4276fba0bd8e55b2d5c132e5a178dd22a2 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 07:53:47 -0300
Subject: [PATCH 03/26] [aarch64] Add support for the __ldxr{8|16|32|64} MS
 intrinsics

These MSVC load-exclusive intrinsics lower to the existing llvm.aarch64.ldxr
intrinsic used by the ACLE __builtin_arm_ldrex builtin.
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 +++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 16 ++++++++++
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 31 +++++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index dd6d4e02c80e2..b3232319f0122 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -419,4 +419,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __stlr16 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned short volatile *, unsigned short)">;
 	def __stlr32 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned int volatile *, unsigned int)">;
 	def __stlr64 : AArch64NoPrefixTargetLibBuiltin<"void (unsigned long long int volatile *, unsigned long long int)">;
+
+	def __ldxr8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char const volatile *)">;
+	def __ldxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
+	def __ldxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
+	def __ldxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile *)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 457a1d38ff1a2..602173dd4ff71 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5344,6 +5344,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Load;
   }
 
+  if (BuiltinID == AArch64::BI__ldxr8 || BuiltinID == AArch64::BI__ldxr16 ||
+      BuiltinID == AArch64::BI__ldxr32 || BuiltinID == AArch64::BI__ldxr64) {
+    // Load-exclusive (LDXR*). Reuse the llvm.aarch64.ldxr lowering of the ACLE
+    // __builtin_arm_ldrex builtin.
+    Value *LoadAddr = EmitScalarExpr(E->getArg(0));
+    QualType Ty = E->getType();
+    llvm::Type *RealResTy = ConvertType(Ty);
+    llvm::Type *IntTy =
+        llvm::IntegerType::get(getLLVMContext(), getContext().getTypeSize(Ty));
+    Function *F = CGM.getIntrinsic(Intrinsic::aarch64_ldxr, DefaultPtrTy);
+    CallInst *Val = Builder.CreateCall(F, LoadAddr, "ldxr");
+    Val->addParamAttr(
+        0, Attribute::get(getLLVMContext(), Attribute::ElementType, IntTy));
+    return Builder.CreateTruncOrBitCast(Val, RealResTy);
+  }
+
   if (BuiltinID == AArch64::BI__stlr8 || BuiltinID == AArch64::BI__stlr16 ||
       BuiltinID == AArch64::BI__stlr32 || BuiltinID == AArch64::BI__stlr64) {
     Value *Ptr = EmitScalarExpr(E->getArg(0));
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 950ecd6aa38cc..ed411c213406b 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -55,6 +55,11 @@ void __stlr16(unsigned __int16 volatile *, unsigned __int16);
 void __stlr32(unsigned __int32 volatile *, unsigned __int32);
 void __stlr64(unsigned __int64 volatile *, unsigned __int64);
 
+unsigned __int8 __ldxr8(const volatile unsigned __int8 *);
+unsigned __int16 __ldxr16(const volatile unsigned __int16 *);
+unsigned __int32 __ldxr32(const volatile unsigned __int32 *);
+unsigned __int64 __ldxr64(const volatile unsigned __int64 *);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 2698a35f0c5aa..a02a61b329a9f 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -700,6 +700,37 @@ unsigned long long int  check__ldar64(unsigned long long int volatile *p) {
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__ldar64'
 
+unsigned char check__ldxr8(unsigned char volatile *p) {
+  return __ldxr8(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__ldxr8(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldxr.p0(ptr elementtype(i8) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i8
+// CHECK-LINUX: error: call to undeclared function '__ldxr8'
+
+unsigned short check__ldxr16(unsigned short volatile *p) {
+  return __ldxr16(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @check__ldxr16(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldxr.p0(ptr elementtype(i16) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i16
+// CHECK-LINUX: error: call to undeclared function '__ldxr16'
+
+unsigned int check__ldxr32(unsigned int volatile *p) {
+  return __ldxr32(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @check__ldxr32(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldxr.p0(ptr elementtype(i32) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i32
+// CHECK-LINUX: error: call to undeclared function '__ldxr32'
+
+unsigned long long int check__ldxr64(unsigned long long int volatile *p) {
+  return __ldxr64(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @check__ldxr64(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldxr.p0(ptr elementtype(i64) %{{.*}})
+// CHECK-LINUX: error: call to undeclared function '__ldxr64'
+
 void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
 {
   __stlr8 (p, v);

>From 56bf2fa3cdd5ec5528e398d8d808d35ebefa1658 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 08:11:24 -0300
Subject: [PATCH 04/26] [aarch64] Add support for the __ldaxr{8|16|32|64} MS
 intrinsics

These MSVC load-acquire-exclusive intrinsics lower to the existing
llvm.aarch64.ldaxr intrinsic used by the ACLE __builtin_arm_ldaex builtin.
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 +++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 16 ++++++++++
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 31 +++++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index b3232319f0122..8fda6505c6a31 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -424,4 +424,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __ldxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
 	def __ldxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
 	def __ldxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile *)">;
+
+	def __ldaxr8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char const volatile *)">;
+	def __ldaxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
+	def __ldaxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
+	def __ldaxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile *)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 602173dd4ff71..d742d5d5102f2 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5360,6 +5360,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Builder.CreateTruncOrBitCast(Val, RealResTy);
   }
 
+  if (BuiltinID == AArch64::BI__ldaxr8 || BuiltinID == AArch64::BI__ldaxr16 ||
+      BuiltinID == AArch64::BI__ldaxr32 || BuiltinID == AArch64::BI__ldaxr64) {
+    // Load-acquire-exclusive (LDAXR*). Reuse the llvm.aarch64.ldaxr lowering of
+    // the ACLE __builtin_arm_ldaex builtin.
+    Value *LoadAddr = EmitScalarExpr(E->getArg(0));
+    QualType Ty = E->getType();
+    llvm::Type *RealResTy = ConvertType(Ty);
+    llvm::Type *IntTy =
+        llvm::IntegerType::get(getLLVMContext(), getContext().getTypeSize(Ty));
+    Function *F = CGM.getIntrinsic(Intrinsic::aarch64_ldaxr, DefaultPtrTy);
+    CallInst *Val = Builder.CreateCall(F, LoadAddr, "ldaxr");
+    Val->addParamAttr(
+        0, Attribute::get(getLLVMContext(), Attribute::ElementType, IntTy));
+    return Builder.CreateTruncOrBitCast(Val, RealResTy);
+  }
+
   if (BuiltinID == AArch64::BI__stlr8 || BuiltinID == AArch64::BI__stlr16 ||
       BuiltinID == AArch64::BI__stlr32 || BuiltinID == AArch64::BI__stlr64) {
     Value *Ptr = EmitScalarExpr(E->getArg(0));
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index ed411c213406b..378f4b4c3d5e3 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -60,6 +60,11 @@ unsigned __int16 __ldxr16(const volatile unsigned __int16 *);
 unsigned __int32 __ldxr32(const volatile unsigned __int32 *);
 unsigned __int64 __ldxr64(const volatile unsigned __int64 *);
 
+unsigned __int8 __ldaxr8(const volatile unsigned __int8 *);
+unsigned __int16 __ldaxr16(const volatile unsigned __int16 *);
+unsigned __int32 __ldaxr32(const volatile unsigned __int32 *);
+unsigned __int64 __ldaxr64(const volatile unsigned __int64 *);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index a02a61b329a9f..e33c6a266b2db 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -731,6 +731,37 @@ unsigned long long int check__ldxr64(unsigned long long int volatile *p) {
 // CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldxr.p0(ptr elementtype(i64) %{{.*}})
 // CHECK-LINUX: error: call to undeclared function '__ldxr64'
 
+unsigned char check__ldaxr8(unsigned char volatile *p) {
+  return __ldaxr8(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__ldaxr8(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldaxr.p0(ptr elementtype(i8) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i8
+// CHECK-LINUX: error: call to undeclared function '__ldaxr8'
+
+unsigned short check__ldaxr16(unsigned short volatile *p) {
+  return __ldaxr16(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @check__ldaxr16(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldaxr.p0(ptr elementtype(i16) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i16
+// CHECK-LINUX: error: call to undeclared function '__ldaxr16'
+
+unsigned int check__ldaxr32(unsigned int volatile *p) {
+  return __ldaxr32(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @check__ldaxr32(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldaxr.p0(ptr elementtype(i32) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i64 %[[RET]] to i32
+// CHECK-LINUX: error: call to undeclared function '__ldaxr32'
+
+unsigned long long int check__ldaxr64(unsigned long long int volatile *p) {
+  return __ldaxr64(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @check__ldaxr64(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldaxr.p0(ptr elementtype(i64) %{{.*}})
+// CHECK-LINUX: error: call to undeclared function '__ldaxr64'
+
 void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
 {
   __stlr8 (p, v);

>From fa1b847b762d407cee5b8ff5ada4adc53392f516 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 08:13:59 -0300
Subject: [PATCH 05/26] [aarch64] Add support for the __stxr{8|16|32|64} MS
 intrinsics

These MSVC store-exclusive intrinsics lower to the existing llvm.aarch64.stxr
intrinsic used by the ACLE __builtin_arm_strex builtin. MSVC takes the
arguments as (pointer, value) (the reverse of the ACLE builtin) and returns
the store status as unsigned char.
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 +++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 22 +++++++++++++
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 32 +++++++++++++++++++
 4 files changed, 64 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 8fda6505c6a31..0fa3d3d9a5266 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -429,4 +429,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __ldaxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
 	def __ldaxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
 	def __ldaxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile *)">;
+
+	def __stxr8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __stxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned short volatile *, unsigned short)">;
+	def __stxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned int volatile *, unsigned int)">;
+	def __stxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index d742d5d5102f2..85cf51c5ee615 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5388,6 +5388,28 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Store;
   }
 
+  if (BuiltinID == AArch64::BI__stxr8 || BuiltinID == AArch64::BI__stxr16 ||
+      BuiltinID == AArch64::BI__stxr32 || BuiltinID == AArch64::BI__stxr64) {
+    // Store-exclusive (STXR*). Reuse the llvm.aarch64.stxr lowering of the ACLE
+    // __builtin_arm_strex builtin. MSVC takes (ptr, value) (the reverse of the
+    // ACLE builtin) and returns the store status as unsigned char.
+    Value *StoreAddr = EmitScalarExpr(E->getArg(0));
+    Value *StoreVal = EmitScalarExpr(E->getArg(1));
+
+    QualType Ty = E->getArg(1)->getType();
+    llvm::Type *StoreTy =
+        llvm::IntegerType::get(getLLVMContext(), getContext().getTypeSize(Ty));
+    StoreVal = Builder.CreateZExtOrBitCast(StoreVal, Int64Ty);
+
+    Function *F =
+        CGM.getIntrinsic(Intrinsic::aarch64_stxr, StoreAddr->getType());
+    CallInst *CI = Builder.CreateCall(F, {StoreVal, StoreAddr}, "stxr");
+    CI->addParamAttr(
+        1, Attribute::get(getLLVMContext(), Attribute::ElementType, StoreTy));
+    return Builder.CreateTrunc(CI, ConvertType(E->getType()));
+  }
+
+
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
         Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)),
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 378f4b4c3d5e3..a0cdd669bca55 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -65,6 +65,11 @@ unsigned __int16 __ldaxr16(const volatile unsigned __int16 *);
 unsigned __int32 __ldaxr32(const volatile unsigned __int32 *);
 unsigned __int64 __ldaxr64(const volatile unsigned __int64 *);
 
+unsigned __int8 __stxr8(volatile unsigned __int8 *, unsigned __int8);
+unsigned __int8 __stxr16(volatile unsigned __int16 *, unsigned __int16);
+unsigned __int8 __stxr32(volatile unsigned __int32 *, unsigned __int32);
+unsigned __int8 __stxr64(volatile unsigned __int64 *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index e33c6a266b2db..fbfbb9ab70851 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -762,6 +762,38 @@ unsigned long long int check__ldaxr64(unsigned long long int volatile *p) {
 // CHECK-MSCOMPAT:       %[[RET:.*]] = call i64 @llvm.aarch64.ldaxr.p0(ptr elementtype(i64) %{{.*}})
 // CHECK-LINUX: error: call to undeclared function '__ldaxr64'
 
+unsigned char check__stxr8(unsigned char volatile *p, unsigned char v) {
+  return __stxr8(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stxr8(ptr{{.*}}%p, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stxr.p0(i64 %{{.*}}, ptr elementtype(i8) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stxr8'
+
+unsigned char check__stxr16(unsigned short volatile *p, unsigned short v) {
+  return __stxr16(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stxr16(ptr{{.*}}%p, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stxr.p0(i64 %{{.*}}, ptr elementtype(i16) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stxr16'
+
+unsigned char check__stxr32(unsigned int volatile *p, unsigned int v) {
+  return __stxr32(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stxr32(ptr{{.*}}%p, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stxr.p0(i64 %{{.*}}, ptr elementtype(i32) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stxr32'
+
+unsigned char check__stxr64(unsigned long long int volatile *p, unsigned long long int v) {
+  return __stxr64(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stxr64(ptr{{.*}}%p, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stxr.p0(i64 %{{.*}}, ptr elementtype(i64) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stxr64'
+
 void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
 {
   __stlr8 (p, v);

>From 3ae3aea6d9097ee8d6899ef459c7f790ea170256 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 08:17:34 -0300
Subject: [PATCH 06/26] [aarch64] Add support for the __stlxr{8|16|32|64} MS
 intrinsics

These MSVC store-release-exclusive intrinsics lower to the existing
llvm.aarch64.stlxr intrinsic used by the ACLE __builtin_arm_stlex builtin.
As with __stxr, MSVC takes the arguments as (pointer, value) and returns the
store status as unsigned char.
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 +++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 19 +++++++----
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 32 +++++++++++++++++++
 4 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 0fa3d3d9a5266..28736e128b7e3 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -434,4 +434,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __stxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned short volatile *, unsigned short)">;
 	def __stxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned int volatile *, unsigned int)">;
 	def __stxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned long long int volatile *, unsigned long long int)">;
+
+	def __stlxr8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __stlxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned short volatile *, unsigned short)">;
+	def __stlxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned int volatile *, unsigned int)">;
+	def __stlxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 85cf51c5ee615..416dfaacfb03b 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5389,10 +5389,16 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
   }
 
   if (BuiltinID == AArch64::BI__stxr8 || BuiltinID == AArch64::BI__stxr16 ||
-      BuiltinID == AArch64::BI__stxr32 || BuiltinID == AArch64::BI__stxr64) {
-    // Store-exclusive (STXR*). Reuse the llvm.aarch64.stxr lowering of the ACLE
-    // __builtin_arm_strex builtin. MSVC takes (ptr, value) (the reverse of the
-    // ACLE builtin) and returns the store status as unsigned char.
+      BuiltinID == AArch64::BI__stxr32 || BuiltinID == AArch64::BI__stxr64 ||
+      BuiltinID == AArch64::BI__stlxr8 || BuiltinID == AArch64::BI__stlxr16 ||
+      BuiltinID == AArch64::BI__stlxr32 || BuiltinID == AArch64::BI__stlxr64) {
+    // Store-(release-)exclusive (STXR*/STLXR*). Reuse the llvm.aarch64.stxr /
+    // stlxr lowering of the ACLE __builtin_arm_strex / stlex builtins. MSVC
+    // takes (ptr, value) (the reverse of the ACLE builtins) and returns the
+    // store status as unsigned char.
+    bool IsRelease =
+        BuiltinID == AArch64::BI__stlxr8 || BuiltinID == AArch64::BI__stlxr16 ||
+        BuiltinID == AArch64::BI__stlxr32 || BuiltinID == AArch64::BI__stlxr64;
     Value *StoreAddr = EmitScalarExpr(E->getArg(0));
     Value *StoreVal = EmitScalarExpr(E->getArg(1));
 
@@ -5401,8 +5407,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
         llvm::IntegerType::get(getLLVMContext(), getContext().getTypeSize(Ty));
     StoreVal = Builder.CreateZExtOrBitCast(StoreVal, Int64Ty);
 
-    Function *F =
-        CGM.getIntrinsic(Intrinsic::aarch64_stxr, StoreAddr->getType());
+    Function *F = CGM.getIntrinsic(
+        IsRelease ? Intrinsic::aarch64_stlxr : Intrinsic::aarch64_stxr,
+        StoreAddr->getType());
     CallInst *CI = Builder.CreateCall(F, {StoreVal, StoreAddr}, "stxr");
     CI->addParamAttr(
         1, Attribute::get(getLLVMContext(), Attribute::ElementType, StoreTy));
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index a0cdd669bca55..3bf6c2cb57091 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -70,6 +70,11 @@ unsigned __int8 __stxr16(volatile unsigned __int16 *, unsigned __int16);
 unsigned __int8 __stxr32(volatile unsigned __int32 *, unsigned __int32);
 unsigned __int8 __stxr64(volatile unsigned __int64 *, unsigned __int64);
 
+unsigned __int8 __stlxr8(volatile unsigned __int8 *, unsigned __int8);
+unsigned __int8 __stlxr16(volatile unsigned __int16 *, unsigned __int16);
+unsigned __int8 __stlxr32(volatile unsigned __int32 *, unsigned __int32);
+unsigned __int8 __stlxr64(volatile unsigned __int64 *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index fbfbb9ab70851..420bf80aa0af2 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -794,6 +794,38 @@ unsigned char check__stxr64(unsigned long long int volatile *p, unsigned long lo
 // CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
 // CHECK-LINUX: error: call to undeclared function '__stxr64'
 
+unsigned char check__stlxr8(unsigned char volatile *p, unsigned char v) {
+  return __stlxr8(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stlxr8(ptr{{.*}}%p, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stlxr.p0(i64 %{{.*}}, ptr elementtype(i8) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stlxr8'
+
+unsigned char check__stlxr16(unsigned short volatile *p, unsigned short v) {
+  return __stlxr16(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stlxr16(ptr{{.*}}%p, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stlxr.p0(i64 %{{.*}}, ptr elementtype(i16) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stlxr16'
+
+unsigned char check__stlxr32(unsigned int volatile *p, unsigned int v) {
+  return __stlxr32(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stlxr32(ptr{{.*}}%p, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stlxr.p0(i64 %{{.*}}, ptr elementtype(i32) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stlxr32'
+
+unsigned char check__stlxr64(unsigned long long int volatile *p, unsigned long long int v) {
+  return __stlxr64(p, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__stlxr64(ptr{{.*}}%p, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[ST:.*]] = call i32 @llvm.aarch64.stlxr.p0(i64 %{{.*}}, ptr elementtype(i64) %{{.*}})
+// CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
+// CHECK-LINUX: error: call to undeclared function '__stlxr64'
+
 void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
 {
   __stlr8 (p, v);

>From 85b1774678beb2a43ee1cc646029ba85ceb39017 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 09:54:55 -0300
Subject: [PATCH 07/26] [AArch64] Add a CRm operand to the llvm.aarch64.clrex
 intrinsic

Parameterize llvm.aarch64.clrex with the CLREX CRm immediate (0-15) so it can
emit "clrex #CRm" instead of always "clrex" (CRm=15), mirroring the
llvm.aarch64.dmb family. The CLREX CRm operand is changed from imm0_15 to the
i32 imm32_0_15 to match the intrinsic argument; assembly is unaffected (same
parser match class). The ACLE __builtin_arm_clrex keeps CRm=15.

This is a prerequisite for implementing the MSVC __clrex(crm) intrinsic.
---
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp        | 3 ++-
 clang/test/CodeGen/builtins-arm-exclusive.c     | 2 +-
 llvm/include/llvm/IR/IntrinsicsAArch64.td       | 2 +-
 llvm/lib/Target/AArch64/AArch64ISelLowering.cpp | 3 ++-
 llvm/lib/Target/AArch64/AArch64InstrAtomics.td  | 5 ++---
 llvm/lib/Target/AArch64/AArch64InstrInfo.td     | 3 ++-
 llvm/test/CodeGen/AArch64/arm64-ldxr-stxr.ll    | 4 ++--
 7 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 416dfaacfb03b..13c9a1e1f7cf5 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -4880,7 +4880,8 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
 
   if (BuiltinID == clang::AArch64::BI__builtin_arm_clrex) {
     Function *F = CGM.getIntrinsic(Intrinsic::aarch64_clrex);
-    return Builder.CreateCall(F);
+    // The ACLE __clrex clears the exclusive monitor with CRm == 15.
+    return Builder.CreateCall(F, {Builder.getInt32(15)});
   }
 
   if (BuiltinID == clang::AArch64::BI_ReadWriteBarrier)
diff --git a/clang/test/CodeGen/builtins-arm-exclusive.c b/clang/test/CodeGen/builtins-arm-exclusive.c
index f27dcfc81f34b..6ca99f235201d 100644
--- a/clang/test/CodeGen/builtins-arm-exclusive.c
+++ b/clang/test/CodeGen/builtins-arm-exclusive.c
@@ -255,7 +255,7 @@ void test_clrex(void) {
 
   __builtin_arm_clrex();
 // CHECK: call void @llvm.arm.clrex()
-// CHECK-ARM64: call void @llvm.aarch64.clrex()
+// CHECK-ARM64: call void @llvm.aarch64.clrex(i32 15)
 }
 
 #ifdef __aarch64__
diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index ba0d7c02bf427..0b91837f3a80a 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -32,7 +32,7 @@ def int_aarch64_stlxp : Intrinsic<[llvm_i32_ty],
                                   [llvm_i64_ty, llvm_i64_ty, llvm_ptr_ty],
                                   [IntrNoFree, IntrWillReturn]>;
 
-def int_aarch64_clrex : Intrinsic<[]>;
+def int_aarch64_clrex : Intrinsic<[], [llvm_i32_ty]>;
 
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index efebe835fa530..52af76da537b6 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -31359,7 +31359,8 @@ Value *AArch64TargetLowering::emitLoadLinked(IRBuilderBase &Builder,
 
 void AArch64TargetLowering::emitAtomicCmpXchgNoStoreLLBalance(
     IRBuilderBase &Builder) const {
-  Builder.CreateIntrinsic(Intrinsic::aarch64_clrex, {});
+  // Clear the exclusive monitor with CRm == 15.
+  Builder.CreateIntrinsic(Intrinsic::aarch64_clrex, {}, {Builder.getInt32(15)});
 }
 
 Value *AArch64TargetLowering::emitStoreConditional(IRBuilderBase &Builder,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 2187f21abb70f..c324b38e56bc0 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -477,9 +477,8 @@ def : Pat<(stlxr_4 (and GPR64:$val, 0xffffffff), GPR64sp:$addr),
           (STLXRW (EXTRACT_SUBREG GPR64:$val, sub_32), GPR64sp:$addr)>;
 
 
-// And clear exclusive.
-
-def : Pat<(int_aarch64_clrex), (CLREX 0xf)>;
+// And clear exclusive. The (int_aarch64_clrex imm) pattern is defined on the
+// CLREX instruction in AArch64InstrInfo.td.
 
 //===----------------------------------
 // Atomic cmpxchg for -O0
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 151cbd9bc5a7c..7bb8037945ee9 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -1583,7 +1583,8 @@ def : InstAlias<"psb $op",  (HINT psbhint_op:$op)>, Requires<[HasSPE]>;
 
 // As far as LLVM is concerned this writes to the system's exclusive monitors.
 let mayLoad = 1, mayStore = 1 in
-def CLREX : CRmSystemI<imm0_15, 0b010, "clrex">;
+def CLREX : CRmSystemI<imm32_0_15, 0b010, "clrex",
+                       [(int_aarch64_clrex (i32 imm32_0_15:$CRm))]>;
 
 // NOTE: ideally, this would have mayStore = 0, mayLoad = 0, but we cannot
 // model patterns with sufficiently fine granularity.
diff --git a/llvm/test/CodeGen/AArch64/arm64-ldxr-stxr.ll b/llvm/test/CodeGen/AArch64/arm64-ldxr-stxr.ll
index ccd191f163b01..11199a2423f8e 100644
--- a/llvm/test/CodeGen/AArch64/arm64-ldxr-stxr.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-ldxr-stxr.ll
@@ -170,11 +170,11 @@ define dso_local void @test_clear() {
 ; CHECK:       // %bb.0:
 ; CHECK-NEXT:    clrex
 ; CHECK-NEXT:    ret
-  call void @llvm.aarch64.clrex()
+  call void @llvm.aarch64.clrex(i32 15)
   ret void
 }
 
-declare void @llvm.aarch64.clrex() nounwind
+declare void @llvm.aarch64.clrex(i32) nounwind
 
 define dso_local i128 @test_load_acquire_i128(ptr %p) nounwind readonly {
 ; CHECK-LABEL: test_load_acquire_i128:

>From b7cd7ceb0c3e647bb26498cbe0dc3297bbe2b213 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 5 Jun 2026 10:04:22 -0300
Subject: [PATCH 08/26] [aarch64] Add support for the __clrex MS intrinsic

The MSVC __clrex(crm) intrinsic clears the local exclusive monitor and emits
"clrex #crm". It lowers to the llvm.aarch64.clrex intrinsic, which now carries
the CRm immediate. Sema restricts crm to a constant in [0, 15].
---
 clang/include/clang/Basic/BuiltinsAArch64.td    | 2 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp        | 8 ++++++++
 clang/lib/Headers/arm64intr.h                   | 2 ++
 clang/lib/Sema/SemaARM.cpp                      | 3 +++
 clang/test/CodeGen/arm64-microsoft-intrinsics.c | 7 +++++++
 clang/test/Sema/builtins-microsoft-arm64.c      | 5 +++++
 6 files changed, 27 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 28736e128b7e3..30515e27679eb 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -439,4 +439,6 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __stlxr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned short volatile *, unsigned short)">;
 	def __stlxr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned int volatile *, unsigned int)">;
 	def __stlxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned long long int volatile *, unsigned long long int)">;
+
+	def __clrex : AArch64NoPrefixTargetLibBuiltin<"void (unsigned char)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 13c9a1e1f7cf5..887a4895f400a 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -4884,6 +4884,14 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Builder.CreateCall(F, {Builder.getInt32(15)});
   }
 
+  if (BuiltinID == clang::AArch64::BI__clrex) {
+    // MSVC __clrex(crm) clears the exclusive monitor with the given CRm (a
+    // constant in [0, 15], enforced by Sema). Emit "clrex #crm".
+    Function *F = CGM.getIntrinsic(Intrinsic::aarch64_clrex);
+    Value *CRm = Builder.CreateZExt(EmitScalarExpr(E->getArg(0)), Int32Ty);
+    return Builder.CreateCall(F, {CRm});
+  }
+
   if (BuiltinID == clang::AArch64::BI_ReadWriteBarrier)
     return Builder.CreateFence(llvm::AtomicOrdering::SequentiallyConsistent,
                                llvm::SyncScope::SingleThread);
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 3bf6c2cb57091..2945eee4cb65a 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -75,6 +75,8 @@ unsigned __int8 __stlxr16(volatile unsigned __int16 *, unsigned __int16);
 unsigned __int8 __stlxr32(volatile unsigned __int32 *, unsigned __int32);
 unsigned __int8 __stlxr64(volatile unsigned __int64 *, unsigned __int64);
 
+void __clrex(unsigned __int8);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/lib/Sema/SemaARM.cpp b/clang/lib/Sema/SemaARM.cpp
index 5e7504fab416d..92cf626545807 100644
--- a/clang/lib/Sema/SemaARM.cpp
+++ b/clang/lib/Sema/SemaARM.cpp
@@ -1189,6 +1189,9 @@ bool SemaARM::CheckAArch64BuiltinFunctionCall(const TargetInfo &TI,
   if (BuiltinID == AArch64::BI__hlt)
     return SemaRef.BuiltinConstantArgRange(TheCall, 0, 0, 0xffff);
 
+  if (BuiltinID == AArch64::BI__clrex)
+    return SemaRef.BuiltinConstantArgRange(TheCall, 0, 0, 15);
+
   if (CheckNeonBuiltinFunctionCall(TI, BuiltinID, TheCall))
     return true;
 
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 420bf80aa0af2..b99e6948c6fd9 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -826,6 +826,13 @@ unsigned char check__stlxr64(unsigned long long int volatile *p, unsigned long l
 // CHECK-MSCOMPAT:       trunc i32 %[[ST]] to i8
 // CHECK-LINUX: error: call to undeclared function '__stlxr64'
 
+void check__clrex(void) {
+  __clrex(15);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}void @check__clrex(){{.*}}{
+// CHECK-MSCOMPAT:       call void @llvm.aarch64.clrex(i32 15)
+// CHECK-LINUX: error: call to undeclared function '__clrex'
+
 void test__stlr8(unsigned __int8 volatile *p, unsigned __int8 v)
 {
   __stlr8 (p, v);
diff --git a/clang/test/Sema/builtins-microsoft-arm64.c b/clang/test/Sema/builtins-microsoft-arm64.c
index 22163ab3fa851..0ec122a8d540f 100644
--- a/clang/test/Sema/builtins-microsoft-arm64.c
+++ b/clang/test/Sema/builtins-microsoft-arm64.c
@@ -14,6 +14,11 @@ void check__hlt() {
   __hlt(65536); // expected-error-re {{argument value {{.*}} is outside the valid range}}
 }
 
+void check__clrex(unsigned char x) {
+  __clrex(16); // expected-error-re {{argument value {{.*}} is outside the valid range}}
+  __clrex(x); // expected-error {{argument to '__clrex' must be a constant integer}}
+}
+
 void check__getReg(void) {
   __getReg(-1); // expected-error-re {{argument value {{.*}} is outside the valid range}}
   __getReg(32); // expected-error-re {{argument value {{.*}} is outside the valid range}}

>From 9079b4a48856806626f9db19fabddc1f8826eed5 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 10:52:29 -0300
Subject: [PATCH 09/26] [aarch64] Add support for cas builtin

The new intrinsic issues CAS* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __casX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 ++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 19 +++++++
 .../lib/Target/AArch64/AArch64InstrFormats.td | 23 ++++++---
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  6 +++
 .../test/CodeGen/AArch64/ms-intrinsics-cas.ll | 50 +++++++++++++++++++
 5 files changed, 106 insertions(+), 7 deletions(-)
 create mode 100644 llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 0b91837f3a80a..8dce37165f035 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -34,6 +34,21 @@ def int_aarch64_stlxp : Intrinsic<[llvm_i32_ty],
 
 def int_aarch64_clrex : Intrinsic<[], [llvm_i32_ty]>;
 
+// CAS intrinsics — emit CAS* (no acquire/release) directly, regardless of the
+// LSE target feature. CAS{H,b} comparand/value use i32; CAS{X}uses i64.
+def int_aarch64_cas8  : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_cas16 : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_cas32 : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_cas64 : Intrinsic<[llvm_i64_ty],
+                                  [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index c324b38e56bc0..9ec3c50ee8e32 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -567,6 +567,25 @@ let Predicates = [HasLSFE] in {
   defm : LDBFPOPregister_patterns<"LDBFMIN",   "atomic_load_fminimum">;
 }
 
+// Unconditional patterns for the __cas* MSVC builtins to emit CAS* regardless
+// of the LSE subtarget feature.  cas{b,h} use only the low bits of the
+// comparison register, so the zero extension masking emitted by CodeGen
+// (zext i8/i16 -> i32 -> 'and w,w,#mask') is redundant.
+def : Pat<(i32 (int_aarch64_cas8  GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 255)),   (and GPR32:$Rt, (i32 255)))),
+          (CASB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_cas8  GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_cas16 GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 65535)), (and GPR32:$Rt, (i32 65535)))),
+          (CASH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_cas16 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_cas32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASW_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_cas64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
+          (CASX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index c252f4933dc18..2aabdb77b8582 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -12403,7 +12403,7 @@ class CryptoRRRi2Tied<bits<1>op0, bits<2>op1, string asm>
 // ST<OP>{<order>}[<size>] <Ws>, [<Xn|SP>]
 // ST<OP>{<order>} <Xs>, [<Xn|SP>]
 
-let Predicates = [HasLSE], mayLoad = 1, mayStore = 1, hasSideEffects = 1 in
+let mayLoad = 1, mayStore = 1, hasSideEffects = 1 in
 class BaseCASEncoding<dag oops, dag iops, string asm, string operands,
                       string cstr, list<dag> pattern>
       : I<oops, iops, asm, operands, cstr, pattern> {
@@ -12424,7 +12424,6 @@ class BaseCASEncoding<dag oops, dag iops, string asm, string operands,
   let Inst{14-10} = 0b11111;
   let Inst{9-5} = Rn;
   let Inst{4-0} = Rt;
-  let Predicates = [HasLSE];
 }
 
 class BaseCAS<string order, string size, RegisterClass RC>
@@ -12435,13 +12434,23 @@ class BaseCAS<string order, string size, RegisterClass RC>
   let NP = 1;
 }
 
-multiclass CompareAndSwap<bits<1> Acq, bits<1> Rel, string order> {
-  let Sz = 0b00, Acq = Acq, Rel = Rel in def B : BaseCAS<order, "b", GPR32>;
-  let Sz = 0b01, Acq = Acq, Rel = Rel in def H : BaseCAS<order, "h", GPR32>;
-  let Sz = 0b10, Acq = Acq, Rel = Rel in def W : BaseCAS<order, "", GPR32>;
-  let Sz = 0b11, Acq = Acq, Rel = Rel in def X : BaseCAS<order, "", GPR64>;
+multiclass CompareAndSwap_impl<bits<1> Acq, bits<1> Rel, string order, list<Predicate> preds, string suffix> {
+  let Predicates = preds, Acq = Acq, Rel = Rel in {
+    let Sz = 0b00 in def "B" # suffix : BaseCAS<order, "b", GPR32>;
+    let Sz = 0b01 in def "H" # suffix : BaseCAS<order, "h", GPR32>;
+    let Sz = 0b10 in def "W" # suffix : BaseCAS<order, "", GPR32>;
+    let Sz = 0b11 in def "X" # suffix : BaseCAS<order, "", GPR64>;
+  }
 }
 
+multiclass CompareAndSwap<bits<1> Acq, bits<1> Rel, string order>
+  : CompareAndSwap_impl<Acq, Rel, order, [HasLSE], "">;
+
+// For isCodeGenOnly use by MS intrinsics that must emit CAS* regardless
+// of the -march setting.
+multiclass CompareAndSwap_cg<bits<1> Acq, bits<1> Rel, string order>
+  : CompareAndSwap_impl<Acq, Rel, order, [], "_cg">;
+
 class BaseCASP<string order, string size, RegisterOperand RC>
       : BaseCASEncoding<(outs RC:$out),(ins RC:$Rs, RC:$Rt, GPR64sp:$Rn),
                         "casp" # order # size, "\t$Rs, $Rt, [$Rn]",
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 7bb8037945ee9..922c53606d507 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3026,6 +3026,12 @@ defm CASA  : CompareAndSwap<1, 0, "a">;
 defm CASL  : CompareAndSwap<0, 1, "l">;
 defm CASAL : CompareAndSwap<1, 1, "al">;
 
+// isCodeGenOnly=1: excluded from asm parser/disassembler, no HasLSE predicate.
+// Used by the __cas* MS intrinsics to force CAS* emission regardless of -march.
+let isCodeGenOnly = 1 in {
+  defm CAS   : CompareAndSwap_cg<0, 0, "">;
+}
+
 // v8.1 atomic CASP
 defm CASP   : CompareAndSwapPair<0, 0, "">;
 defm CASPA  : CompareAndSwapPair<1, 0, "a">;
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
new file mode 100644
index 0000000000000..b3ee250bd96c3
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
@@ -0,0 +1,50 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-none-linux-gnu -fast-isel=0 -global-isel=false \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-none-linux-gnu -mattr=+lse -fast-isel=0 \
+; RUN:     -global-isel=false -verify-machineinstrs < %s | FileCheck %s
+
+; Tests for the __cas* MS builtins on AArch64.  These lower to
+; llvm.aarch64.cas* intrinsics and must select the corresponding CAS instruction
+; regardless of whether +lse is present in the target features (the _cg ISel
+; variants have no feature predicate).
+
+define i32 @test_cas8(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_cas8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casb w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.cas8(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_cas16(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_cas16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cash w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.cas16(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_cas32(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_cas32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cas w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.cas32(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i64 @test_cas64(ptr %p, i64 %rs, i64 %rt) {
+; CHECK-LABEL: test_cas64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cas x1, x2, [x0]
+; CHECK-NEXT:    mov x0, x1
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.cas64(ptr %p, i64 %rs, i64 %rt)
+  ret i64 %r
+}
\ No newline at end of file

>From bd9d251ff03878689bb724999ad37dd19e1db55f Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Wed, 15 Apr 2026 16:53:14 -0300
Subject: [PATCH 10/26] [aarch64] Add support for the __cas{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__cas8`  - maps to CASB.
* `__cas16` - maps to CASH.
* `__cas32` - maps to CAS.
* `__cas64` - maps to CAS.

The emit is done using new intrisincs to issue CAS* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 40 +++++++++++++
 clang/lib/Headers/arm64intr.h                 |  9 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 56 +++++++++++++++++++
 4 files changed, 110 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 30515e27679eb..340655a5349f3 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -441,4 +441,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __stlxr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned long long int volatile *, unsigned long long int)">;
 
 	def __clrex : AArch64NoPrefixTargetLibBuiltin<"void (unsigned char)">;
+
+	def __cas8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char, unsigned char)">;
+	def __cas16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
+	def __cas32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
+	def __cas64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 887a4895f400a..29c009bef5e6f 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5425,6 +5425,46 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Builder.CreateTrunc(CI, ConvertType(E->getType()));
   }
 
+  if (BuiltinID == AArch64::BI__cas8 || BuiltinID == AArch64::BI__cas16 ||
+      BuiltinID == AArch64::BI__cas32 || BuiltinID == AArch64::BI__cas64) {
+    unsigned IntrID;
+    llvm::Type *IntrArgTy;
+    switch (BuiltinID) {
+    case AArch64::BI__cas8:
+      IntrID = Intrinsic::aarch64_cas8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__cas16:
+      IntrID = Intrinsic::aarch64_cas16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__cas32:
+      IntrID = Intrinsic::aarch64_cas32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__cas64:
+      IntrID = Intrinsic::aarch64_cas64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
+    default:
+      llvm_unreachable("missing builtin ID in switch!");
+    }
+    Value *Ptr = EmitScalarExpr(E->getArg(0));
+    Value *Comp = EmitScalarExpr(E->getArg(1));
+    Value *Val = EmitScalarExpr(E->getArg(2));
+    // For 8/16-bit we need to zext to GRP size
+    if (Comp->getType() != IntrArgTy)
+      Comp = Builder.CreateZExt(Comp, IntrArgTy);
+    if (Val->getType() != IntrArgTy)
+      Val = Builder.CreateZExt(Val, IntrArgTy);
+    Value *Result =
+        Builder.CreateCall(CGM.getIntrinsic(IntrID), {Ptr, Comp, Val});
+    // CAS{B/H} return i32 (zero-extended); truncate to declared type.
+    llvm::Type *RetTy = ConvertType(E->getType());
+    if (Result->getType() != RetTy)
+      Result = Builder.CreateTrunc(Result, RetTy);
+    return Result;
+  }
 
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 2945eee4cb65a..2540ac8bc5e4c 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -77,6 +77,15 @@ unsigned __int8 __stlxr64(volatile unsigned __int64 *, unsigned __int64);
 
 void __clrex(unsigned __int8);
 
+unsigned __int8 __cas8(unsigned __int8 volatile *, unsigned __int8,
+                       unsigned __int8);
+unsigned __int16 __cas16(unsigned __int16 volatile *, unsigned __int16,
+                         unsigned __int16);
+unsigned __int32 __cas32(unsigned __int32 volatile *, unsigned __int32,
+                         unsigned __int32);
+unsigned __int64 __cas64(unsigned __int64 volatile *, unsigned __int64,
+                         unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index b99e6948c6fd9..7fff821012269 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -877,6 +877,62 @@ void test__stlr64(unsigned __int64 volatile *p, unsigned __int64 v)
 // CHECK-MSCOMPAT:       ret void
 // CHECK-LINUX: error: call to undeclared function '__stlr64'
 
+unsigned char test__cas8(unsigned char volatile* t, unsigned char c, unsigned char v)
+{
+  return __cas8 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__cas8(ptr{{.*}}%t, i8{{.*}}%c, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i8, ptr %c.addr, align 1
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i8 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.cas8(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__cas8'
+
+unsigned short test__cas16(unsigned short volatile* t, unsigned short c, unsigned short v)
+{
+  return __cas16 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__cas16(ptr{{.*}}%t, i16{{.*}}%c, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i16, ptr %c.addr, align 2
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i16 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i16 %[[TMPV]] to i32 
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.cas16(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__cas16'
+
+unsigned int test__cas32(unsigned int volatile* t, unsigned int c, unsigned int v)
+{
+  return __cas32 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__cas32(ptr{{.*}}%t, i32{{.*}}%c, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i32, ptr %c.addr, align 4
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.cas32(ptr %[[TMPT]], i32 %[[TMPC]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__cas32'
+
+unsigned long long int test__cas64(unsigned long long int volatile* t,
+                                   unsigned long long int c,
+                                   unsigned long long int v)
+{
+  return __cas64 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__cas64(ptr{{.*}}%t, i64{{.*}}%c, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i64, ptr %c.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.cas64(ptr %[[TMPT]], i64 %[[TMPC]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__cas64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From dd9545dcb2fb24ee957d17d0adc61bd17082cbad Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 12:16:24 -0300
Subject: [PATCH 11/26] [aarch64] Add support for casa builtin

The new intrinsic issues CASA* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __casaX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 +++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 16 ++++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-cas.ll | 40 +++++++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 8dce37165f035..bd8747efb7c02 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -49,6 +49,21 @@ def int_aarch64_cas64 : Intrinsic<[llvm_i64_ty],
                                   [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
                                   [IntrNoFree, IntrWillReturn]>;
 
+// CASA intrinsics — emit CASA* (acquire, no release) directly, regardless of
+// the LSE target feature. Same type conventions as cas*.
+def int_aarch64_casa8  : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casa16 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casa32 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casa64 : Intrinsic<[llvm_i64_ty],
+                                   [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 9ec3c50ee8e32..57b19d97b41a5 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -586,6 +586,22 @@ def : Pat<(i32 (int_aarch64_cas32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
 def : Pat<(i64 (int_aarch64_cas64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
           (CASX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
 
+// Unconditional patterns for the __casa* MSVC builtins (acquire ordering).
+def : Pat<(i32 (int_aarch64_casa8  GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 255)),   (and GPR32:$Rt, (i32 255)))),
+          (CASAB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casa8  GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASAB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casa16 GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 65535)), (and GPR32:$Rt, (i32 65535)))),
+          (CASAH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casa16 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASAH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casa32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASAW_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_casa64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
+          (CASAX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 922c53606d507..29a480078a51b 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3030,6 +3030,7 @@ defm CASAL : CompareAndSwap<1, 1, "al">;
 // Used by the __cas* MS intrinsics to force CAS* emission regardless of -march.
 let isCodeGenOnly = 1 in {
   defm CAS   : CompareAndSwap_cg<0, 0, "">;
+  defm CASA  : CompareAndSwap_cg<1, 0, "a">;
 }
 
 // v8.1 atomic CASP
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
index b3ee250bd96c3..99f1e5b50132f 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
@@ -47,4 +47,44 @@ define i64 @test_cas64(ptr %p, i64 %rs, i64 %rt) {
 ; CHECK-NEXT:    ret
   %r = call i64 @llvm.aarch64.cas64(ptr %p, i64 %rs, i64 %rt)
   ret i64 %r
+}
+
+define i32 @test_casa8(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casa8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casab w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casa8(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casa16(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casa16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casah w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casa16(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casa32(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casa32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casa w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casa32(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i64 @test_casa64(ptr %p, i64 %rs, i64 %rt) {
+; CHECK-LABEL: test_casa64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casa x1, x2, [x0]
+; CHECK-NEXT:    mov x0, x1
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.casa64(ptr %p, i64 %rs, i64 %rt)
+  ret i64 %r
 }
\ No newline at end of file

>From 7be34dabcd9b94f6d6b9d4fcfdb81352ea775d04 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Wed, 15 Apr 2026 17:39:55 -0300
Subject: [PATCH 12/26] [aarch64] Add support for the __casa{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__casa8`  - maps to CASAB.
* `__casa16` - maps to CASAH.
* `__casa32` - maps to CASA.
* `__casa64` - maps to CASA.

The emit is done using new intrisincs to issue CASA* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 ++++++-
 clang/lib/Headers/arm64intr.h                 |  9 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 56 +++++++++++++++++++
 4 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 340655a5349f3..b88f38654a665 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -446,4 +446,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __cas16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
 	def __cas32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
 	def __cas64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
+	def __casa8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char, unsigned char)">;
+	def __casa16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
+	def __casa32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
+	def __casa64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 29c009bef5e6f..bca38762082ab 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5426,7 +5426,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
   }
 
   if (BuiltinID == AArch64::BI__cas8 || BuiltinID == AArch64::BI__cas16 ||
-      BuiltinID == AArch64::BI__cas32 || BuiltinID == AArch64::BI__cas64) {
+      BuiltinID == AArch64::BI__cas32 || BuiltinID == AArch64::BI__cas64 ||
+      BuiltinID == AArch64::BI__casa8 || BuiltinID == AArch64::BI__casa16 ||
+      BuiltinID == AArch64::BI__casa32 || BuiltinID == AArch64::BI__casa64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5446,6 +5448,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_cas64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__casa8:
+      IntrID = Intrinsic::aarch64_casa8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casa16:
+      IntrID = Intrinsic::aarch64_casa16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casa32:
+      IntrID = Intrinsic::aarch64_casa32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casa64:
+      IntrID = Intrinsic::aarch64_casa64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 2540ac8bc5e4c..18e6cef556900 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -86,6 +86,15 @@ unsigned __int32 __cas32(unsigned __int32 volatile *, unsigned __int32,
 unsigned __int64 __cas64(unsigned __int64 volatile *, unsigned __int64,
                          unsigned __int64);
 
+unsigned __int8 __casa8(unsigned __int8 volatile *, unsigned __int8,
+                        unsigned __int8);
+unsigned __int16 __casa16(unsigned __int16 volatile *, unsigned __int16,
+                          unsigned __int16);
+unsigned __int32 __casa32(unsigned __int32 volatile *, unsigned __int32,
+                          unsigned __int32);
+unsigned __int64 __casa64(unsigned __int64 volatile *, unsigned __int64,
+                          unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 7fff821012269..87df4c5901ac8 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -933,6 +933,62 @@ unsigned long long int test__cas64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__cas64'
 
+unsigned char test__casa8(unsigned char volatile* t, unsigned char c, unsigned char v)
+{
+  return __casa8 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__casa8(ptr{{.*}}%t, i8{{.*}}%c, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i8, ptr %c.addr, align 1
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i8 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casa8(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casa8'
+
+unsigned short test__casa16(unsigned short volatile* t, unsigned short c, unsigned short v)
+{
+  return __casa16 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__casa16(ptr{{.*}}%t, i16{{.*}}%c, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i16, ptr %c.addr, align 2
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i16 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casa16(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casa16'
+
+unsigned int test__casa32(unsigned int volatile* t, unsigned int c, unsigned int v)
+{
+  return __casa32 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__casa32(ptr{{.*}}%t, i32{{.*}}%c, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i32, ptr %c.addr, align 4
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casa32(ptr %[[TMPT]], i32 %[[TMPC]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casa32'
+
+unsigned long long int test__casa64(unsigned long long int volatile* t,
+                                    unsigned long long int c,
+                                    unsigned long long int v)
+{
+  return __casa64 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__casa64(ptr{{.*}}%t, i64{{.*}}%c, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i64, ptr %c.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.casa64(ptr %[[TMPT]], i64 %[[TMPC]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casa64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 9ddcb1bc3801ff7c6bd1db2224647a3ebeedab3f Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 13:06:36 -0300
Subject: [PATCH 13/26] [aarch64] Add support for casl builtin

The new intrinsic issues CASL* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __caslX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 +++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 16 +++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-cas.ll | 42 ++++++++++++++++++-
 4 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index bd8747efb7c02..61f8a26d625b4 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -64,6 +64,21 @@ def int_aarch64_casa64 : Intrinsic<[llvm_i64_ty],
                                    [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
                                    [IntrNoFree, IntrWillReturn]>;
 
+// CASL intrinsics — emit CASL* (release) directly, regardless of the LSE
+// target feature. Same type conventions as cas*.
+def int_aarch64_casl8  : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casl16 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casl32 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casl64 : Intrinsic<[llvm_i64_ty],
+                                   [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 57b19d97b41a5..12f108a77b518 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -602,6 +602,22 @@ def : Pat<(i32 (int_aarch64_casa32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
 def : Pat<(i64 (int_aarch64_casa64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
           (CASAX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
 
+// Unconditional patterns for the __casl* MSVC builtins (release ordering).
+def : Pat<(i32 (int_aarch64_casl8  GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 255)),   (and GPR32:$Rt, (i32 255)))),
+          (CASLB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casl8  GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASLB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casl16 GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 65535)), (and GPR32:$Rt, (i32 65535)))),
+          (CASLH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casl16 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASLH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casl32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASLW_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_casl64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
+          (CASLX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 29a480078a51b..34bc7569bb5ab 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3031,6 +3031,7 @@ defm CASAL : CompareAndSwap<1, 1, "al">;
 let isCodeGenOnly = 1 in {
   defm CAS   : CompareAndSwap_cg<0, 0, "">;
   defm CASA  : CompareAndSwap_cg<1, 0, "a">;
+  defm CASL  : CompareAndSwap_cg<0, 1, "l">;
 }
 
 // v8.1 atomic CASP
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
index 99f1e5b50132f..717f23b8910f5 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
@@ -87,4 +87,44 @@ define i64 @test_casa64(ptr %p, i64 %rs, i64 %rt) {
 ; CHECK-NEXT:    ret
   %r = call i64 @llvm.aarch64.casa64(ptr %p, i64 %rs, i64 %rt)
   ret i64 %r
-}
\ No newline at end of file
+}
+
+define i32 @test_casl8(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casl8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    caslb w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casl8(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casl16(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casl16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    caslh w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casl16(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casl32(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casl32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casl w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casl32(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i64 @test_casl64(ptr %p, i64 %rs, i64 %rt) {
+; CHECK-LABEL: test_casl64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casl x1, x2, [x0]
+; CHECK-NEXT:    mov x0, x1
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.casl64(ptr %p, i64 %rs, i64 %rt)
+  ret i64 %r
+}

>From 70373ccf862e00e8f95aa80a6c6dd955fbcbcc3e Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 16 Apr 2026 09:15:28 -0300
Subject: [PATCH 14/26] [aarch64] Add support for the __casl{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__casl8`  - maps to CASLB.
* `__casl16` - maps to CASLH.
* `__casl32` - maps to CASL.
* `__casl64` - maps to CASL.

The emit is done using new intrisincs to issue CASL* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 ++++++-
 clang/lib/Headers/arm64intr.h                 |  9 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 56 +++++++++++++++++++
 4 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index b88f38654a665..9dcacc6f2e991 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -450,4 +450,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __casa16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
 	def __casa32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
 	def __casa64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
+	def __casl8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char, unsigned char)">;
+	def __casl16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
+	def __casl32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
+	def __casl64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index bca38762082ab..52f87b11e7510 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5428,7 +5428,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
   if (BuiltinID == AArch64::BI__cas8 || BuiltinID == AArch64::BI__cas16 ||
       BuiltinID == AArch64::BI__cas32 || BuiltinID == AArch64::BI__cas64 ||
       BuiltinID == AArch64::BI__casa8 || BuiltinID == AArch64::BI__casa16 ||
-      BuiltinID == AArch64::BI__casa32 || BuiltinID == AArch64::BI__casa64) {
+      BuiltinID == AArch64::BI__casa32 || BuiltinID == AArch64::BI__casa64 ||
+      BuiltinID == AArch64::BI__casl8 || BuiltinID == AArch64::BI__casl16 ||
+      BuiltinID == AArch64::BI__casl32 || BuiltinID == AArch64::BI__casl64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5464,6 +5466,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_casa64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__casl8:
+      IntrID = Intrinsic::aarch64_casl8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casl16:
+      IntrID = Intrinsic::aarch64_casl16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casl32:
+      IntrID = Intrinsic::aarch64_casl32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casl64:
+      IntrID = Intrinsic::aarch64_casl64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 18e6cef556900..75c56c0ad8303 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -95,6 +95,15 @@ unsigned __int32 __casa32(unsigned __int32 volatile *, unsigned __int32,
 unsigned __int64 __casa64(unsigned __int64 volatile *, unsigned __int64,
                           unsigned __int64);
 
+unsigned __int8 __casl8(unsigned __int8 volatile *, unsigned __int8,
+                        unsigned __int8);
+unsigned __int16 __casl16(unsigned __int16 volatile *, unsigned __int16,
+                          unsigned __int16);
+unsigned __int32 __casl32(unsigned __int32 volatile *, unsigned __int32,
+                          unsigned __int32);
+unsigned __int64 __casl64(unsigned __int64 volatile *, unsigned __int64,
+                          unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 87df4c5901ac8..e2c9cc9599045 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -989,6 +989,62 @@ unsigned long long int test__casa64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__casa64'
 
+unsigned char test__casl8(unsigned char volatile* t, unsigned char c, unsigned char v)
+{
+  return __casl8 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__casl8(ptr{{.*}}%t, i8{{.*}}%c, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i8, ptr %c.addr, align 1
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i8 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casl8(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casl8'
+
+unsigned short test__casl16(unsigned short volatile* t, unsigned short c, unsigned short v)
+{
+  return __casl16 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__casl16(ptr{{.*}}%t, i16{{.*}}%c, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i16, ptr %c.addr, align 2
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i16 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casl16(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casl16'
+
+unsigned int test__casl32(unsigned int volatile* t, unsigned int c, unsigned int v)
+{
+  return __casl32 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__casl32(ptr{{.*}}%t, i32{{.*}}%c, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i32, ptr %c.addr, align 4
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casl32(ptr %[[TMPT]], i32 %[[TMPC]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casl32'
+
+unsigned long long int test__casl64(unsigned long long int volatile* t,
+                                    unsigned long long int c,
+                                    unsigned long long int v)
+{
+  return __casl64 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__casl64(ptr{{.*}}%t, i64{{.*}}%c, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i64, ptr %c.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.casl64(ptr %[[TMPT]], i64 %[[TMPC]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casl64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 62c79906113b22447629d4a729c6064360fc31e1 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 13:28:11 -0300
Subject: [PATCH 15/26] [aarch64] Add support for casal builtin

The new intrinsic issues CASAL* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __casalX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 +++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 16 ++++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-cas.ll | 40 +++++++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 61f8a26d625b4..29b30b7d51d60 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -79,6 +79,21 @@ def int_aarch64_casl64 : Intrinsic<[llvm_i64_ty],
                                    [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
                                    [IntrNoFree, IntrWillReturn]>;
 
+// CASAL intrinsics — emit CASAL* (acquire/release) directly, regardless of the LSE
+// target feature. Same type conventions as cas*.
+def int_aarch64_casal8  : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casal16 : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casal32 : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_casal64 : Intrinsic<[llvm_i64_ty],
+                                    [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 12f108a77b518..f6fb0433cf7f5 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -618,6 +618,22 @@ def : Pat<(i32 (int_aarch64_casl32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
 def : Pat<(i64 (int_aarch64_casl64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
           (CASLX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
 
+// Unconditional patterns for the __casal* MSVC builtins (acquire/release ordering).
+def : Pat<(i32 (int_aarch64_casal8  GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 255)),   (and GPR32:$Rt, (i32 255)))),
+          (CASALB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casal8  GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASALB_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casal16 GPR64sp:$Rn,
+               (and GPR32:$Rs, (i32 65535)), (and GPR32:$Rt, (i32 65535)))),
+          (CASALH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casal16 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASALH_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_casal32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
+          (CASALW_cg GPR32:$Rs, GPR32:$Rt, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_casal64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
+          (CASALX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 34bc7569bb5ab..87f4fbd4f21b7 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3032,6 +3032,7 @@ let isCodeGenOnly = 1 in {
   defm CAS   : CompareAndSwap_cg<0, 0, "">;
   defm CASA  : CompareAndSwap_cg<1, 0, "a">;
   defm CASL  : CompareAndSwap_cg<0, 1, "l">;
+  defm CASAL : CompareAndSwap_cg<1, 1, "al">;
 }
 
 // v8.1 atomic CASP
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
index 717f23b8910f5..bb2d7ae508ed5 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-cas.ll
@@ -128,3 +128,43 @@ define i64 @test_casl64(ptr %p, i64 %rs, i64 %rt) {
   %r = call i64 @llvm.aarch64.casl64(ptr %p, i64 %rs, i64 %rt)
   ret i64 %r
 }
+
+define i32 @test_casal8(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casal8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casalb w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casal8(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casal16(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casal16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casalh w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casal16(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i32 @test_casal32(ptr %p, i32 %rs, i32 %rt) {
+; CHECK-LABEL: test_casal32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casal w1, w2, [x0]
+; CHECK-NEXT:    mov w0, w1
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.casal32(ptr %p, i32 %rs, i32 %rt)
+  ret i32 %r
+}
+
+define i64 @test_casal64(ptr %p, i64 %rs, i64 %rt) {
+; CHECK-LABEL: test_casal64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    casal x1, x2, [x0]
+; CHECK-NEXT:    mov x0, x1
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.casal64(ptr %p, i64 %rs, i64 %rt)
+  ret i64 %r
+}

>From 1be53f0e73dd0e46cc5207ce4215a4687850277a Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 16 Apr 2026 10:47:20 -0300
Subject: [PATCH 16/26] [aarch64] Add support for the __casal{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__casal8`  - maps to CASALB.
* `__casal16` - maps to CASALH.
* `__casal32` - maps to CASAL.
* `__casal64` - maps to CASAL.

The emit is done using new intrisincs to issue CASAL* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 ++++++-
 clang/lib/Headers/arm64intr.h                 |  9 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 56 +++++++++++++++++++
 4 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 9dcacc6f2e991..b166bf1bb7f88 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -454,4 +454,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __casl16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
 	def __casl32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
 	def __casl64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
+	def __casal8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char, unsigned char)">;
+	def __casal16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
+	def __casal32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
+	def __casal64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 52f87b11e7510..dae1038da3e98 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5430,7 +5430,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       BuiltinID == AArch64::BI__casa8 || BuiltinID == AArch64::BI__casa16 ||
       BuiltinID == AArch64::BI__casa32 || BuiltinID == AArch64::BI__casa64 ||
       BuiltinID == AArch64::BI__casl8 || BuiltinID == AArch64::BI__casl16 ||
-      BuiltinID == AArch64::BI__casl32 || BuiltinID == AArch64::BI__casl64) {
+      BuiltinID == AArch64::BI__casl32 || BuiltinID == AArch64::BI__casl64 ||
+      BuiltinID == AArch64::BI__casal8 || BuiltinID == AArch64::BI__casal16 ||
+      BuiltinID == AArch64::BI__casal32 || BuiltinID == AArch64::BI__casal64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5482,6 +5484,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_casl64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__casal8:
+      IntrID = Intrinsic::aarch64_casal8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casal16:
+      IntrID = Intrinsic::aarch64_casal16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casal32:
+      IntrID = Intrinsic::aarch64_casal32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__casal64:
+      IntrID = Intrinsic::aarch64_casal64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 75c56c0ad8303..ca0fc81742384 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -104,6 +104,15 @@ unsigned __int32 __casl32(unsigned __int32 volatile *, unsigned __int32,
 unsigned __int64 __casl64(unsigned __int64 volatile *, unsigned __int64,
                           unsigned __int64);
 
+unsigned __int8 __casal8(unsigned __int8 volatile *, unsigned __int8,
+                         unsigned __int8);
+unsigned __int16 __casal16(unsigned __int16 volatile *, unsigned __int16,
+                           unsigned __int16);
+unsigned __int32 __casal32(unsigned __int32 volatile *, unsigned __int32,
+                           unsigned __int32);
+unsigned __int64 __casal64(unsigned __int64 volatile *, unsigned __int64,
+                           unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index e2c9cc9599045..65ee33185c364 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1045,6 +1045,62 @@ unsigned long long int test__casl64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__casl64'
 
+unsigned char test__casal8(unsigned char volatile* t, unsigned char c, unsigned char v)
+{
+  return __casal8 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__casal8(ptr{{.*}}%t, i8{{.*}}%c, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i8, ptr %c.addr, align 1
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i8 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casal8(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casal8'
+
+unsigned short test__casal16(unsigned short volatile* t, unsigned short c, unsigned short v)
+{
+  return __casal16 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__casal16(ptr{{.*}}%t, i16{{.*}}%c, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i16, ptr %c.addr, align 2
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTC:[0-9]+]] = zext i16 %[[TMPC]] to i32
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]]  = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casal16(ptr %[[TMPT]], i32 %[[ZEXTC]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[RETT:[0-9]+]]  = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[RETT]]
+// CHECK-LINUX: error: call to undeclared function '__casal16'
+
+unsigned int test__casal32(unsigned int volatile* t, unsigned int c, unsigned int v)
+{
+  return __casal32 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__casal32(ptr{{.*}}%t, i32{{.*}}%c, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i32, ptr %c.addr, align 4
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.casal32(ptr %[[TMPT]], i32 %[[TMPC]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casal32'
+
+unsigned long long int test__casal64(unsigned long long int volatile* t,
+                                     unsigned long long int c,
+                                     unsigned long long int v)
+{
+  return __casal64 (t, c, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__casal64(ptr{{.*}}%t, i64{{.*}}%c, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPC:[0-9]+]] = load i64, ptr %c.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.casal64(ptr %[[TMPT]], i64 %[[TMPC]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__casal64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 9b79b8fa5fb5ae868a94bada80e2f279c4dfe137 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 15:33:25 -0300
Subject: [PATCH 17/26] [aarch64] Add support for swp builtin

The new intrinsic issues SWP* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __swpX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 ++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 16 +++++++
 .../lib/Target/AArch64/AArch64InstrFormats.td | 21 ++++++---
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  6 +++
 .../test/CodeGen/AArch64/ms-intrinsics-swp.ll | 46 +++++++++++++++++++
 5 files changed, 98 insertions(+), 6 deletions(-)
 create mode 100644 llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 29b30b7d51d60..d17edb7935ce4 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -94,6 +94,21 @@ def int_aarch64_casal64 : Intrinsic<[llvm_i64_ty],
                                     [llvm_ptr_ty, llvm_i64_ty, llvm_i64_ty],
                                     [IntrNoFree, IntrWillReturn]>;
 
+// SWP intrinsics — emit SWP* (no acquire/release) directly, regardless of the
+// LSE target feature. swp{b,h} value uses i32; swp64 uses i64.
+def int_aarch64_swp8  : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swp16 : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swp32 : Intrinsic<[llvm_i32_ty],
+                                  [llvm_ptr_ty, llvm_i32_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swp64 : Intrinsic<[llvm_i64_ty],
+                                  [llvm_ptr_ty, llvm_i64_ty],
+                                  [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index f6fb0433cf7f5..08d187363828c 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -634,6 +634,22 @@ def : Pat<(i32 (int_aarch64_casal32 GPR64sp:$Rn, GPR32:$Rs, GPR32:$Rt)),
 def : Pat<(i64 (int_aarch64_casal64 GPR64sp:$Rn, GPR64:$Rs, GPR64:$Rt)),
           (CASALX_cg GPR64:$Rs, GPR64:$Rt, GPR64sp:$Rn)>;
 
+// Unconditional patterns for the __swp* MSVC builtins (no ordering).
+// As with swp{b,h}, the zero-extension mask may survive or be eliminated by the
+// DAG combiner, so both masked and plain forms are needed.
+def : Pat<(i32 (int_aarch64_swp8  GPR64sp:$Rn, (and GPR32:$Rs, (i32 255)))),
+          (SWPB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swp8  GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swp16 GPR64sp:$Rn, (and GPR32:$Rs, (i32 65535)))),
+          (SWPH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swp16 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swp32 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPW_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_swp64 GPR64sp:$Rn, GPR64:$Rs)),
+          (SWPX_cg GPR64:$Rs, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index 2aabdb77b8582..d0f1a60e4f2cd 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -12531,16 +12531,25 @@ class BaseSWP<string order, string size, RegisterClass RC>
   let Inst{11-10} = 0b00;
   let Inst{9-5} = Rn;
   let Inst{4-0} = Rt;
-  let Predicates = [HasLSE];
 }
 
-multiclass Swap<bits<1> Acq, bits<1> Rel, string order> {
-  let Sz = 0b00, Acq = Acq, Rel = Rel in def B : BaseSWP<order, "b", GPR32>;
-  let Sz = 0b01, Acq = Acq, Rel = Rel in def H : BaseSWP<order, "h", GPR32>;
-  let Sz = 0b10, Acq = Acq, Rel = Rel in def W : BaseSWP<order, "", GPR32>;
-  let Sz = 0b11, Acq = Acq, Rel = Rel in def X : BaseSWP<order, "", GPR64>;
+multiclass Swap_impl<bits<1> Acq, bits<1> Rel, string order, list<Predicate> preds, string suffix> {
+  let Predicates = preds, Acq = Acq, Rel = Rel in {
+    let Sz = 0b00 in def "B" # suffix : BaseSWP<order, "b", GPR32>;
+    let Sz = 0b01 in def "H" # suffix : BaseSWP<order, "h", GPR32>;
+    let Sz = 0b10 in def "W" # suffix : BaseSWP<order, "",  GPR32>;
+    let Sz = 0b11 in def "X" # suffix : BaseSWP<order, "",  GPR64>;
+  }
 }
 
+multiclass Swap<bits<1> Acq, bits<1> Rel, string order>
+  : Swap_impl<Acq, Rel, order, [HasLSE], "">;
+
+// Like Swap but without the HasLSE predicate — for isCodeGenOnly use by
+// MS intrinsics that must emit SWP* regardless of the -march setting.
+multiclass Swap_cg<bits<1> Acq, bits<1> Rel, string order>
+  : Swap_impl<Acq, Rel, order, [], "_cg">;
+
 // v9.6a swap operations
 class BaseSWPLSUI<string order, RegisterClass RC>
        : I<(outs RC:$Rt),(ins RC:$Rs, GPR64sp:$Rn), "swpt" # order,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 87f4fbd4f21b7..753389a68399a 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3061,6 +3061,12 @@ defm SWPA  : Swap<1, 0, "a">;
 defm SWPL  : Swap<0, 1, "l">;
 defm SWPAL : Swap<1, 1, "al">;
 
+// isCodeGenOnly=1: excluded from asm parser/disassembler, no HasLSE predicate.
+// Used by the __swp* MS intrinsics to force SWP* emission regardless of -march.
+let isCodeGenOnly = 1 in {
+  defm SWP  : Swap_cg<0, 0, "">;
+}
+
 // v9.6a atomic swap (FEAT_LSUI)
 let Predicates = [HasLSUI] in {
   defm SWPT   : SwapLSUI<0, 0, "">;
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
new file mode 100644
index 0000000000000..f670a9157ba6d
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
@@ -0,0 +1,46 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-windows-msvc -fast-isel=0 -global-isel=false \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-windows-msvc -mattr=+lse -fast-isel=0 \
+; RUN:     -global-isel=false -verify-machineinstrs < %s | FileCheck %s
+
+; Tests for the __swp* MS builtins on AArch64. These lower to
+; llvm.aarch64.swp* intrinsics and must select SWP* regardless of whether
+; +lse is present in the target features (the _cg ISel variants have no
+; feature predicate).
+
+define i32 @test_swp8(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swp8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpb w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swp8(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swp16(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swp16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swph w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swp16(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swp32(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swp32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swp w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swp32(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i64 @test_swp64(ptr %p, i64 %v) {
+; CHECK-LABEL: test_swp64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swp x1, x0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.swp64(ptr %p, i64 %v)
+  ret i64 %r
+}
\ No newline at end of file

>From b22dc8916fce27b5ff52df72e6cf7c6317622719 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 17 Apr 2026 10:05:23 -0300
Subject: [PATCH 18/26] [aarch64] Add support for the __swp{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__swp8`   - maps to SWPB.
* `__swp16`  - maps to SWPH.
* `__swp32`  - maps to SWP.
* `__swp64`  - maps to SWP.

The emit is done using new intrisincs to issue SWP* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 36 ++++++++++++++
 clang/lib/Headers/arm64intr.h                 |  5 ++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 49 +++++++++++++++++++
 4 files changed, 95 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index b166bf1bb7f88..8c9ca4214a9af 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -458,4 +458,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __casal16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short, unsigned short)">;
 	def __casal32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int, unsigned int)">;
 	def __casal64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int, unsigned long long int)">;
+
+	def __swp8 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __swp16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
+	def __swp32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
+	def __swp64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index dae1038da3e98..8829698a0f91b 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5520,6 +5520,42 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Result;
   }
 
+  if (BuiltinID == AArch64::BI__swp8 || BuiltinID == AArch64::BI__swp16 ||
+      BuiltinID == AArch64::BI__swp32 || BuiltinID == AArch64::BI__swp64) {
+    unsigned IntrID;
+    llvm::Type *IntrArgTy;
+    switch (BuiltinID) {
+    case AArch64::BI__swp8:
+      IntrID = Intrinsic::aarch64_swp8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swp16:
+      IntrID = Intrinsic::aarch64_swp16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swp32:
+      IntrID = Intrinsic::aarch64_swp32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swp64:
+      IntrID = Intrinsic::aarch64_swp64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
+    default:
+      llvm_unreachable("missing builtin ID in switch!");
+    }
+    Value *Ptr = EmitScalarExpr(E->getArg(0));
+    Value *Val = EmitScalarExpr(E->getArg(1));
+    if (Val->getType() != IntrArgTy)
+      Val = Builder.CreateZExt(Val, IntrArgTy);
+    Value *Result = Builder.CreateCall(CGM.getIntrinsic(IntrID), {Ptr, Val});
+    // SWP{B/H} return i32 (zero-extended); truncate to declared type.
+    llvm::Type *RetTy = ConvertType(E->getType());
+    if (Result->getType() != RetTy)
+      Result = Builder.CreateTrunc(Result, RetTy);
+    return Result;
+  }
+
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
         Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)),
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index ca0fc81742384..49b6ca312b8e5 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -113,6 +113,11 @@ unsigned __int32 __casal32(unsigned __int32 volatile *, unsigned __int32,
 unsigned __int64 __casal64(unsigned __int64 volatile *, unsigned __int64,
                            unsigned __int64);
 
+unsigned __int8 __swp8(unsigned __int8 volatile *, unsigned __int8);
+unsigned __int16 __swp16(unsigned __int16 volatile *, unsigned __int16);
+unsigned __int32 __swp32(unsigned __int32 volatile *, unsigned __int32);
+unsigned __int64 __swp64(unsigned __int64 volatile *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 65ee33185c364..cf02c83d5f041 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1101,6 +1101,55 @@ unsigned long long int test__casal64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__casal64'
 
+unsigned char test__swp8(unsigned char volatile* t, unsigned char v)
+{
+  return __swp8(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__swp8(ptr{{.*}}%t, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swp8(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swp8'
+
+unsigned short test__swp16(unsigned short volatile* t, unsigned short v)
+{
+  return __swp16(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__swp16(ptr{{.*}}%t, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swp16(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swp16'
+
+unsigned int test__swp32(unsigned int volatile* t, unsigned int v)
+{
+  return __swp32(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__swp32(ptr{{.*}}%t, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swp32(ptr %[[TMPT]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swp32'
+
+unsigned long long int test__swp64(unsigned long long int volatile* t,
+                                   unsigned long long int v)
+{
+  return __swp64(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__swp64(ptr{{.*}}%t, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.swp64(ptr %[[TMPT]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swp64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 47fbc4735e8c14a5b1e155d2b0d5cbf237ea78cc Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 16:27:26 -0300
Subject: [PATCH 19/26] [aarch64] Add support for swpa builtin

The new intrinsic issues SWPA* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __swpaX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 14 +++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 13 +++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-swp.ll | 37 +++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index d17edb7935ce4..d529a9e91d36e 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -109,6 +109,20 @@ def int_aarch64_swp64 : Intrinsic<[llvm_i64_ty],
                                   [llvm_ptr_ty, llvm_i64_ty],
                                   [IntrNoFree, IntrWillReturn]>;
 
+// SWPA intrinsics — emit SWPA (acquire) directly, regardless of the LSE target
+def int_aarch64_swpa8  : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpa16 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpa32 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpa64 : Intrinsic<[llvm_i64_ty],
+                                   [llvm_ptr_ty, llvm_i64_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 08d187363828c..ce12ff7ad8bee 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -650,6 +650,19 @@ def : Pat<(i32 (int_aarch64_swp32 GPR64sp:$Rn, GPR32:$Rs)),
 def : Pat<(i64 (int_aarch64_swp64 GPR64sp:$Rn, GPR64:$Rs)),
           (SWPX_cg GPR64:$Rs, GPR64sp:$Rn)>;
 
+def : Pat<(i32 (int_aarch64_swpa8  GPR64sp:$Rn, (and GPR32:$Rs, (i32 255)))),
+          (SWPAB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpa8  GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPAB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpa16 GPR64sp:$Rn, (and GPR32:$Rs, (i32 65535)))),
+          (SWPAH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpa16 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPAH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpa32 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPAW_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_swpa64 GPR64sp:$Rn, GPR64:$Rs)),
+          (SWPAX_cg GPR64:$Rs, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 753389a68399a..5de42cbaf6d87 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3065,6 +3065,7 @@ defm SWPAL : Swap<1, 1, "al">;
 // Used by the __swp* MS intrinsics to force SWP* emission regardless of -march.
 let isCodeGenOnly = 1 in {
   defm SWP  : Swap_cg<0, 0, "">;
+  defm SWPA : Swap_cg<1, 0, "a">;
 }
 
 // v9.6a atomic swap (FEAT_LSUI)
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
index f670a9157ba6d..d170a6d33218d 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
@@ -43,4 +43,41 @@ define i64 @test_swp64(ptr %p, i64 %v) {
 ; CHECK-NEXT:    ret
   %r = call i64 @llvm.aarch64.swp64(ptr %p, i64 %v)
   ret i64 %r
+}
+
+
+define i32 @test_swpa8(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpa8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpab w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpa8(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpa16(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpa16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpah w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpa16(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpa32(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpa32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpa w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpa32(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i64 @test_swpa64(ptr %p, i64 %v) {
+; CHECK-LABEL: test_swpa64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpa x1, x0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.swpa64(ptr %p, i64 %v)
+  ret i64 %r
 }
\ No newline at end of file

>From 91a9836f5b69568a6fc7e726b607ad940b431553 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 17 Apr 2026 12:41:03 -0300
Subject: [PATCH 20/26] [aarch64] Add support for the __swpa{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__swpa8`  - maps to SWPAB.
* `__swpa16` - maps to SWPAH.
* `__swpa32` - maps to SWPA.
* `__swpa64` - maps to SWPA.

The emit is done using new intrisincs to issue SWPA* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 +++++++-
 clang/lib/Headers/arm64intr.h                 |  5 ++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 49 +++++++++++++++++++
 4 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 8c9ca4214a9af..1df9ade3a9a81 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -463,4 +463,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __swp16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
 	def __swp32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
 	def __swp64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
+	def __swpa8 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __swpa16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
+	def __swpa32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
+	def __swpa64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 8829698a0f91b..f509d6a6092ad 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5521,7 +5521,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
   }
 
   if (BuiltinID == AArch64::BI__swp8 || BuiltinID == AArch64::BI__swp16 ||
-      BuiltinID == AArch64::BI__swp32 || BuiltinID == AArch64::BI__swp64) {
+      BuiltinID == AArch64::BI__swp32 || BuiltinID == AArch64::BI__swp64 ||
+      BuiltinID == AArch64::BI__swpa8 || BuiltinID == AArch64::BI__swpa16 ||
+      BuiltinID == AArch64::BI__swpa32 || BuiltinID == AArch64::BI__swpa64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5541,6 +5543,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_swp64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__swpa8:
+      IntrID = Intrinsic::aarch64_swpa8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpa16:
+      IntrID = Intrinsic::aarch64_swpa16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpa32:
+      IntrID = Intrinsic::aarch64_swpa32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpa64:
+      IntrID = Intrinsic::aarch64_swpa64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 49b6ca312b8e5..21d7029d82533 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -118,6 +118,11 @@ unsigned __int16 __swp16(unsigned __int16 volatile *, unsigned __int16);
 unsigned __int32 __swp32(unsigned __int32 volatile *, unsigned __int32);
 unsigned __int64 __swp64(unsigned __int64 volatile *, unsigned __int64);
 
+unsigned __int8 __swpa8(unsigned __int8 volatile *, unsigned __int8);
+unsigned __int16 __swpa16(unsigned __int16 volatile *, unsigned __int16);
+unsigned __int32 __swpa32(unsigned __int32 volatile *, unsigned __int32);
+unsigned __int64 __swpa64(unsigned __int64 volatile *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index cf02c83d5f041..356dbd5c3d450 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1150,6 +1150,55 @@ unsigned long long int test__swp64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__swp64'
 
+unsigned char test__swpa8(unsigned char volatile* t, unsigned char v)
+{
+  return __swpa8(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__swpa8(ptr{{.*}}%t, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpa8(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpa8'
+
+unsigned short test__swpa16(unsigned short volatile* t, unsigned short v)
+{
+  return __swpa16(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__swpa16(ptr{{.*}}%t, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpa16(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpa16'
+
+unsigned int test__swpa32(unsigned int volatile* t, unsigned int v)
+{
+  return __swpa32(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__swpa32(ptr{{.*}}%t, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpa32(ptr %[[TMPT]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpa32'
+
+unsigned long long int test__swpa64(unsigned long long int volatile* t,
+                                    unsigned long long int v)
+{
+  return __swpa64(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__swpa64(ptr{{.*}}%t, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.swpa64(ptr %[[TMPT]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpa64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 51f264e884b1838e20d06849f0a07f9e07f18ae7 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 18:06:06 -0300
Subject: [PATCH 21/26] [aarch64] Add support for swpl builtin

The new intrinsic issues SWPL* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __swplX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 14 +++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 13 +++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-swp.ll | 38 ++++++++++++++++++-
 4 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index d529a9e91d36e..9c87644ba476d 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -123,6 +123,20 @@ def int_aarch64_swpa64 : Intrinsic<[llvm_i64_ty],
                                    [llvm_ptr_ty, llvm_i64_ty],
                                    [IntrNoFree, IntrWillReturn]>;
 
+// SWPL intrinsics — emit SWPL (release) directly, regardless of the LSE target
+def int_aarch64_swpl8  : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpl16 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpl32 : Intrinsic<[llvm_i32_ty],
+                                   [llvm_ptr_ty, llvm_i32_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpl64 : Intrinsic<[llvm_i64_ty],
+                                   [llvm_ptr_ty, llvm_i64_ty],
+                                   [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index ce12ff7ad8bee..2496a8990da61 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -663,6 +663,19 @@ def : Pat<(i32 (int_aarch64_swpa32 GPR64sp:$Rn, GPR32:$Rs)),
 def : Pat<(i64 (int_aarch64_swpa64 GPR64sp:$Rn, GPR64:$Rs)),
           (SWPAX_cg GPR64:$Rs, GPR64sp:$Rn)>;
 
+def : Pat<(i32 (int_aarch64_swpl8  GPR64sp:$Rn, (and GPR32:$Rs, (i32 255)))),
+          (SWPLB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpl8  GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPLB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpl16 GPR64sp:$Rn, (and GPR32:$Rs, (i32 65535)))),
+          (SWPLH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpl16 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPLH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpl32 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPLW_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_swpl64 GPR64sp:$Rn, GPR64:$Rs)),
+          (SWPLX_cg GPR64:$Rs, GPR64sp:$Rn)>;
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 5de42cbaf6d87..a559ff4863cc5 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3066,6 +3066,7 @@ defm SWPAL : Swap<1, 1, "al">;
 let isCodeGenOnly = 1 in {
   defm SWP  : Swap_cg<0, 0, "">;
   defm SWPA : Swap_cg<1, 0, "a">;
+  defm SWPL : Swap_cg<0, 1, "l">;
 }
 
 // v9.6a atomic swap (FEAT_LSUI)
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
index d170a6d33218d..4275b1ced09b6 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
@@ -80,4 +80,40 @@ define i64 @test_swpa64(ptr %p, i64 %v) {
 ; CHECK-NEXT:    ret
   %r = call i64 @llvm.aarch64.swpa64(ptr %p, i64 %v)
   ret i64 %r
-}
\ No newline at end of file
+}
+
+define i32 @test_swpl8(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpl8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swplb w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpl8(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpl16(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpl16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swplh w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpl16(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpl32(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpl32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpl w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpl32(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i64 @test_swpl64(ptr %p, i64 %v) {
+; CHECK-LABEL: test_swpl64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpl x1, x0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.swpl64(ptr %p, i64 %v)
+  ret i64 %r
+}

>From ce898533061244f010bbedbefb9b13021e1d69cd Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 17 Apr 2026 13:02:47 -0300
Subject: [PATCH 22/26] [aarch64] Add support for the __swpl{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__swpl8`   - maps to SWPLB.
* `__swpl16`  - maps to SWPLH.
* `__swpl32`  - maps to SWPL.
* `__swpl64`  - maps to SWPL.

The emit is done using new intrisincs to issue SWPL* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 +++++++-
 clang/lib/Headers/arm64intr.h                 |  5 ++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 49 +++++++++++++++++++
 4 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 1df9ade3a9a81..13627a0abbc7a 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -467,4 +467,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __swpa16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
 	def __swpa32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
 	def __swpa64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
+	def __swpl8 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __swpl16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
+	def __swpl32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
+	def __swpl64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index f509d6a6092ad..2d418ef7bf3cb 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5523,7 +5523,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
   if (BuiltinID == AArch64::BI__swp8 || BuiltinID == AArch64::BI__swp16 ||
       BuiltinID == AArch64::BI__swp32 || BuiltinID == AArch64::BI__swp64 ||
       BuiltinID == AArch64::BI__swpa8 || BuiltinID == AArch64::BI__swpa16 ||
-      BuiltinID == AArch64::BI__swpa32 || BuiltinID == AArch64::BI__swpa64) {
+      BuiltinID == AArch64::BI__swpa32 || BuiltinID == AArch64::BI__swpa64 ||
+      BuiltinID == AArch64::BI__swpl8 || BuiltinID == AArch64::BI__swpl16 ||
+      BuiltinID == AArch64::BI__swpl32 || BuiltinID == AArch64::BI__swpl64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5559,6 +5561,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_swpa64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__swpl8:
+      IntrID = Intrinsic::aarch64_swpl8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpl16:
+      IntrID = Intrinsic::aarch64_swpl16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpl32:
+      IntrID = Intrinsic::aarch64_swpl32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpl64:
+      IntrID = Intrinsic::aarch64_swpl64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 21d7029d82533..707f43c51a422 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -123,6 +123,11 @@ unsigned __int16 __swpa16(unsigned __int16 volatile *, unsigned __int16);
 unsigned __int32 __swpa32(unsigned __int32 volatile *, unsigned __int32);
 unsigned __int64 __swpa64(unsigned __int64 volatile *, unsigned __int64);
 
+unsigned __int8 __swpl8(unsigned __int8 volatile *, unsigned __int8);
+unsigned __int16 __swpl16(unsigned __int16 volatile *, unsigned __int16);
+unsigned __int32 __swpl32(unsigned __int32 volatile *, unsigned __int32);
+unsigned __int64 __swpl64(unsigned __int64 volatile *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 356dbd5c3d450..e379bb615ecf6 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1199,6 +1199,55 @@ unsigned long long int test__swpa64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__swpa64'
 
+unsigned char test__swpl8(unsigned char volatile* t, unsigned char v)
+{
+  return __swpl8(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__swpl8(ptr{{.*}}%t, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpl8(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpl8'
+
+unsigned short test__swpl16(unsigned short volatile* t, unsigned short v)
+{
+  return __swpl16(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__swpl16(ptr{{.*}}%t, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpl16(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpl16'
+
+unsigned int test__swpl32(unsigned int volatile* t, unsigned int v)
+{
+  return __swpl32(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__swpl32(ptr{{.*}}%t, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpl32(ptr %[[TMPT]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpl32'
+
+unsigned long long int test__swpl64(unsigned long long int volatile* t,
+                                    unsigned long long int v)
+{
+  return __swpl64(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__swpl64(ptr{{.*}}%t, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.swpl64(ptr %[[TMPT]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpl64'
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From 7bc1b42f2a8fe21e0d8c66259422ddf626ed0c25 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Thu, 23 Apr 2026 18:23:55 -0300
Subject: [PATCH 23/26] [aarch64] Add support for swpal builtin

The new intrinsic issues SWPAL* instruction directly, regardless of LSE
target features.  This will be used to implement MSVC __swpalX
builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 ++++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td | 13 +++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  1 +
 .../test/CodeGen/AArch64/ms-intrinsics-swp.ll | 36 +++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 9c87644ba476d..3e5cd1b945ec5 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -137,6 +137,21 @@ def int_aarch64_swpl64 : Intrinsic<[llvm_i64_ty],
                                    [llvm_ptr_ty, llvm_i64_ty],
                                    [IntrNoFree, IntrWillReturn]>;
 
+// SWPAL intrinsics — emit SWPAL* (no acquire/release) directly, regardless of the
+// LSE target feature.
+def int_aarch64_swpal8  : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpal16 : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpal32 : Intrinsic<[llvm_i32_ty],
+                                    [llvm_ptr_ty, llvm_i32_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+def int_aarch64_swpal64 : Intrinsic<[llvm_i64_ty],
+                                    [llvm_ptr_ty, llvm_i64_ty],
+                                    [IntrNoFree, IntrWillReturn]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 2496a8990da61..74d40ac64de7a 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -676,6 +676,19 @@ def : Pat<(i32 (int_aarch64_swpl32 GPR64sp:$Rn, GPR32:$Rs)),
 def : Pat<(i64 (int_aarch64_swpl64 GPR64sp:$Rn, GPR64:$Rs)),
           (SWPLX_cg GPR64:$Rs, GPR64sp:$Rn)>;
 
+def : Pat<(i32 (int_aarch64_swpal8  GPR64sp:$Rn, (and GPR32:$Rs, (i32 255)))),
+          (SWPALB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpal8  GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPALB_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpal16 GPR64sp:$Rn, (and GPR32:$Rs, (i32 65535)))),
+          (SWPALH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpal16 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPALH_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_swpal32 GPR64sp:$Rn, GPR32:$Rs)),
+          (SWPALW_cg GPR32:$Rs, GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_swpal64 GPR64sp:$Rn, GPR64:$Rs)),
+          (SWPALX_cg GPR64:$Rs, GPR64sp:$Rn)>;     
+
 // v8.9a/v9.4a FEAT_LRCPC patterns
 let Predicates = [HasRCPC3, HasNEON] in {
   // LDAP1 loads
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index a559ff4863cc5..b3cc2db450484 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -3067,6 +3067,7 @@ let isCodeGenOnly = 1 in {
   defm SWP  : Swap_cg<0, 0, "">;
   defm SWPA : Swap_cg<1, 0, "a">;
   defm SWPL : Swap_cg<0, 1, "l">;
+  defm SWPAL : Swap_cg<1, 1, "al">;
 }
 
 // v9.6a atomic swap (FEAT_LSUI)
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
index 4275b1ced09b6..c01fee0c9e1ff 100644
--- a/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-swp.ll
@@ -117,3 +117,39 @@ define i64 @test_swpl64(ptr %p, i64 %v) {
   %r = call i64 @llvm.aarch64.swpl64(ptr %p, i64 %v)
   ret i64 %r
 }
+
+define i32 @test_swpal8(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpal8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpalb w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpal8(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpal16(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpal16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpalh w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpal16(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i32 @test_swpal32(ptr %p, i32 %v) {
+; CHECK-LABEL: test_swpal32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpal w1, w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.swpal32(ptr %p, i32 %v)
+  ret i32 %r
+}
+
+define i64 @test_swpal64(ptr %p, i64 %v) {
+; CHECK-LABEL: test_swpal64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    swpal x1, x0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.swpal64(ptr %p, i64 %v)
+  ret i64 %r
+}

>From 2d44fbf88bd01860655fd3ec6163f051753e01af Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Fri, 17 Apr 2026 13:20:15 -0300
Subject: [PATCH 24/26] [aarch64] Add support for the __swpal{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__swpal8`  - maps to SWPALB.
* `__swpal16` - maps to SWPALH.
* `__swpal32` - maps to SWPAL.
* `__swpal64` - maps to SWPAL.

The emit is done using new intrisincs to issue SWPAL* instruction
directly, regardless of LSE target feature.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  4 ++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 20 +++++++-
 clang/lib/Headers/arm64intr.h                 |  5 ++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 50 +++++++++++++++++++
 4 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 13627a0abbc7a..e8fc874595eae 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -471,4 +471,8 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __swpl16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
 	def __swpl32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
 	def __swpl64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
+	def __swpal8 : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char volatile *, unsigned char)">;
+	def __swpal16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
+	def __swpal32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
+	def __swpal64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 2d418ef7bf3cb..c4540124cc40f 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5525,7 +5525,9 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       BuiltinID == AArch64::BI__swpa8 || BuiltinID == AArch64::BI__swpa16 ||
       BuiltinID == AArch64::BI__swpa32 || BuiltinID == AArch64::BI__swpa64 ||
       BuiltinID == AArch64::BI__swpl8 || BuiltinID == AArch64::BI__swpl16 ||
-      BuiltinID == AArch64::BI__swpl32 || BuiltinID == AArch64::BI__swpl64) {
+      BuiltinID == AArch64::BI__swpl32 || BuiltinID == AArch64::BI__swpl64 ||
+      BuiltinID == AArch64::BI__swpal8 || BuiltinID == AArch64::BI__swpal16 ||
+      BuiltinID == AArch64::BI__swpal32 || BuiltinID == AArch64::BI__swpal64) {
     unsigned IntrID;
     llvm::Type *IntrArgTy;
     switch (BuiltinID) {
@@ -5577,6 +5579,22 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
       IntrID = Intrinsic::aarch64_swpl64;
       IntrArgTy = Builder.getInt64Ty();
       break;
+    case AArch64::BI__swpal8:
+      IntrID = Intrinsic::aarch64_swpal8;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpal16:
+      IntrID = Intrinsic::aarch64_swpal16;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpal32:
+      IntrID = Intrinsic::aarch64_swpal32;
+      IntrArgTy = Builder.getInt32Ty();
+      break;
+    case AArch64::BI__swpal64:
+      IntrID = Intrinsic::aarch64_swpal64;
+      IntrArgTy = Builder.getInt64Ty();
+      break;
     default:
       llvm_unreachable("missing builtin ID in switch!");
     }
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 707f43c51a422..3d6701cc78902 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -128,6 +128,11 @@ unsigned __int16 __swpl16(unsigned __int16 volatile *, unsigned __int16);
 unsigned __int32 __swpl32(unsigned __int32 volatile *, unsigned __int32);
 unsigned __int64 __swpl64(unsigned __int64 volatile *, unsigned __int64);
 
+unsigned __int8 __swpal8(unsigned __int8 volatile *, unsigned __int8);
+unsigned __int16 __swpal16(unsigned __int16 volatile *, unsigned __int16);
+unsigned __int32 __swpal32(unsigned __int32 volatile *, unsigned __int32);
+unsigned __int64 __swpal64(unsigned __int64 volatile *, unsigned __int64);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index e379bb615ecf6..2caf2c40b8a29 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1248,6 +1248,56 @@ unsigned long long int test__swpl64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__swpl64'
 
+unsigned char test__swpal8(unsigned char volatile* t, unsigned char v)
+{
+  return __swpal8(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @test__swpal8(ptr{{.*}}%t, i8{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i8, ptr %v.addr, align 1
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i8 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpal8(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpal8'
+
+unsigned short test__swpal16(unsigned short volatile* t, unsigned short v)
+{
+  return __swpal16(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @test__swpal16(ptr{{.*}}%t, i16{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i16, ptr %v.addr, align 2
+// CHECK-MSCOMPAT:       %[[ZEXTV:[0-9]+]] = zext i16 %[[TMPV]] to i32
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpal16(ptr %[[TMPT]], i32 %[[ZEXTV]])
+// CHECK-MSCOMPAT:       %[[TRUNC:[0-9]+]] = trunc i32 %[[RET]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[TRUNC]]
+// CHECK-LINUX: error: call to undeclared function '__swpal16'
+
+unsigned int test__swpal32(unsigned int volatile* t, unsigned int v)
+{
+  return __swpal32(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @test__swpal32(ptr{{.*}}%t, i32{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i32, ptr %v.addr, align 4
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.swpal32(ptr %[[TMPT]], i32 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpal32'
+
+unsigned long long int test__swpal64(unsigned long long int volatile* t,
+                                     unsigned long long int v)
+{
+  return __swpal64(t, v);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @test__swpal64(ptr{{.*}}%t, i64{{.*}}%v){{.*}}{
+// CHECK-MSCOMPAT:       %[[TMPT:[0-9]+]] = load ptr, ptr %t.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMPV:[0-9]+]] = load i64, ptr %v.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.swpal64(ptr %[[TMPT]], i64 %[[TMPV]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__swpal64'
+
+
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}
 // CHECK-MSCOMPAT: ![[MD4]] = !{!"d5"}

>From c9a3bd47725d238fe09525db8508921f959716d5 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Wed, 22 Apr 2026 16:26:44 -0300
Subject: [PATCH 25/26] [aarch64] Add support for ldarp builtin

The new intrinsic issues LDAPR* instruction directly, regardless of RCPC
target features.  This will be used to implement MSVC __ldaprX builtins.
---
 llvm/include/llvm/IR/IntrinsicsAArch64.td     | 15 ++++++
 .../lib/Target/AArch64/AArch64InstrAtomics.td |  7 +++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  8 ++++
 .../CodeGen/AArch64/ms-intrinsics-ldapr.ll    | 46 +++++++++++++++++++
 4 files changed, 76 insertions(+)
 create mode 100644 llvm/test/CodeGen/AArch64/ms-intrinsics-ldapr.ll

diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 3e5cd1b945ec5..c19bd837018f1 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -152,6 +152,21 @@ def int_aarch64_swpal64 : Intrinsic<[llvm_i64_ty],
                                     [llvm_ptr_ty, llvm_i64_ty],
                                     [IntrNoFree, IntrWillReturn]>;
 
+// LDAPR intrinsics — emit LDAPR* directly, regardless of RCPC target feature.
+// LDAPRB/H/W return i32 (zero-extended into GPR32); LDAPRX returns i64.
+def int_aarch64_ldapr8  : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty],
+                                    [IntrNoFree, IntrWillReturn,
+                                     IntrReadMem, IntrArgMemOnly]>;
+def int_aarch64_ldapr16 : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty],
+                                    [IntrNoFree, IntrWillReturn,
+                                     IntrReadMem, IntrArgMemOnly]>;
+def int_aarch64_ldapr32 : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty],
+                                    [IntrNoFree, IntrWillReturn,
+                                     IntrReadMem, IntrArgMemOnly]>;
+def int_aarch64_ldapr64 : Intrinsic<[llvm_i64_ty], [llvm_ptr_ty],
+                                    [IntrNoFree, IntrWillReturn,
+                                     IntrReadMem, IntrArgMemOnly]>;
+
 def int_aarch64_sdiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
                                 LLVMMatchType<0>], [IntrNoMem]>;
 def int_aarch64_udiv : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>,
diff --git a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
index 74d40ac64de7a..c5ee58e4c60ed 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrAtomics.td
@@ -60,6 +60,13 @@ let Predicates = [HasRCPC] in {
   def : Pat<(acquiring_load<atomic_load_nonext_64> GPR64sp:$ptr), (LDAPRX GPR64sp:$ptr)>;
 }
 
+// Unconditional patterns for the __ldapr* MSVC builtins. These force LDAPR*
+// emission regardless of the RCPC subtarget feature.
+def : Pat<(i32 (int_aarch64_ldapr8  GPR64sp:$Rn)), (LDAPRB_cg GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_ldapr16 GPR64sp:$Rn)), (LDAPRH_cg GPR64sp:$Rn)>;
+def : Pat<(i32 (int_aarch64_ldapr32 GPR64sp:$Rn)), (LDAPRW_cg GPR64sp:$Rn)>;
+def : Pat<(i64 (int_aarch64_ldapr64 GPR64sp:$Rn)), (LDAPRX_cg GPR64sp:$Rn)>;
+
 // 8-bit loads
 def : Pat<(seq_cst_load<atomic_load_azext_8>  GPR64sp:$ptr), (LDARB GPR64sp:$ptr)>;
 def : Pat<(acquiring_load<atomic_load_azext_8>  GPR64sp:$ptr), (LDARB GPR64sp:$ptr)>;
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index b3cc2db450484..122fa59754749 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -1933,6 +1933,14 @@ let Predicates = [HasRCPC] in {
   def LDAPRX  : RCPCLoad<0b11, "ldapr", GPR64>;
 }
 
+// Code-gen-only LDAPR variants for the __ldapr* MSVC builtins.
+let isCodeGenOnly = 1 in {
+  def LDAPRB_cg : RCPCLoad<0b00, "ldaprb", GPR32>;
+  def LDAPRH_cg : RCPCLoad<0b01, "ldaprh", GPR32>;
+  def LDAPRW_cg : RCPCLoad<0b10, "ldapr", GPR32>;
+  def LDAPRX_cg : RCPCLoad<0b11, "ldapr", GPR64>;
+}
+
 // v8.3a complex add and multiply-accumulate. No predicate here, that is done
 // inside the multiclass as the FP16 versions need different predicates.
 defm FCMLA : SIMDThreeSameVectorTiedComplexHSD<1, 0b110, complexrotateop,
diff --git a/llvm/test/CodeGen/AArch64/ms-intrinsics-ldapr.ll b/llvm/test/CodeGen/AArch64/ms-intrinsics-ldapr.ll
new file mode 100644
index 0000000000000..1c1073a16bdb9
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ms-intrinsics-ldapr.ll
@@ -0,0 +1,46 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-windows-msvc -fast-isel=0 -global-isel=false \
+; RUN:     -verify-machineinstrs < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-windows-msvc -mattr=+rcpc -fast-isel=0 \
+; RUN:     -global-isel=false -verify-machineinstrs < %s | FileCheck %s
+
+; Tests for the __ldapr* MS builtins on AArch64. These lower to the
+; llvm.aarch64.ldaprN intrinsics and must select ldaprb/h/w/x regardless
+; of whether +rcpc is present in the target features (the _cg ISel variants
+; have no feature predicate).
+
+define i32 @test_ldapr8(ptr %p) {
+; CHECK-LABEL: test_ldapr8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldaprb w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.ldapr8(ptr %p)
+  ret i32 %r
+}
+
+define i32 @test_ldapr16(ptr %p) {
+; CHECK-LABEL: test_ldapr16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldaprh w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.ldapr16(ptr %p)
+  ret i32 %r
+}
+
+define i32 @test_ldapr32(ptr %p) {
+; CHECK-LABEL: test_ldapr32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldapr w0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i32 @llvm.aarch64.ldapr32(ptr %p)
+  ret i32 %r
+}
+
+define i64 @test_ldapr64(ptr %p) {
+; CHECK-LABEL: test_ldapr64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldapr x0, [x0]
+; CHECK-NEXT:    ret
+  %r = call i64 @llvm.aarch64.ldapr64(ptr %p)
+  ret i64 %r
+}
\ No newline at end of file

>From eb71b1e6c97231fb95c560c3ecfd41742eed5508 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <zatrazz at gmail.com>
Date: Tue, 14 Apr 2026 11:27:39 -0300
Subject: [PATCH 26/26] [aarch64] Add support for the __ldapr{8|16|32|64} MS
 intrinsics

Adds support for the following MSVC intrinsics:
* `__ldapr8`  - LDAPRB
* `__ldapr16` - LDAPRH
* `__ldapr32` - LDAPR
* `__ldapr64` - LDAPR

The emit is done using new intrisincs to issue LDAPR* instruction
directly, regardless of RCPC target features.  This mimics MSVC compiler
and the idea of the builtin to mimic an inline asm.

These are documented at:
<https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics?view=msvc-180>
---
 clang/include/clang/Basic/BuiltinsAArch64.td  |  5 +++
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      | 26 +++++++++++++
 clang/lib/Headers/arm64intr.h                 |  5 +++
 .../test/CodeGen/arm64-microsoft-intrinsics.c | 37 +++++++++++++++++++
 4 files changed, 73 insertions(+)

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index e8fc874595eae..4b9e97b9949b7 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -475,4 +475,9 @@ let Attributes = [NoThrow, RequireDeclaration], Languages = "ALL_MS_LANGUAGES",
 	def __swpal16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short volatile *, unsigned short)">;
 	def __swpal32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int volatile *, unsigned int)">;
 	def __swpal64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int volatile *, unsigned long long int)">;
+
+	def __ldapr8  : AArch64NoPrefixTargetLibBuiltin<"unsigned char (unsigned char const volatile *)">;
+	def __ldapr16 : AArch64NoPrefixTargetLibBuiltin<"unsigned short (unsigned short const volatile *)">;
+	def __ldapr32 : AArch64NoPrefixTargetLibBuiltin<"unsigned int (unsigned int const volatile *)">;
+	def __ldapr64 : AArch64NoPrefixTargetLibBuiltin<"unsigned long long int (unsigned long long int const volatile *)">;
 }
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index c4540124cc40f..51d1b214d4e2c 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -5610,6 +5610,32 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Result;
   }
 
+  if (BuiltinID == AArch64::BI__ldapr8 || BuiltinID == AArch64::BI__ldapr16 ||
+      BuiltinID == AArch64::BI__ldapr32 || BuiltinID == AArch64::BI__ldapr64) {
+    unsigned IntrID;
+    switch (BuiltinID) {
+    case AArch64::BI__ldapr8:
+      IntrID = Intrinsic::aarch64_ldapr8;
+      break;
+    case AArch64::BI__ldapr16:
+      IntrID = Intrinsic::aarch64_ldapr16;
+      break;
+    case AArch64::BI__ldapr32:
+      IntrID = Intrinsic::aarch64_ldapr32;
+      break;
+    default:
+      IntrID = Intrinsic::aarch64_ldapr64;
+      break;
+    }
+    Value *Ptr = EmitScalarExpr(E->getArg(0));
+    Value *Result = Builder.CreateCall(CGM.getIntrinsic(IntrID), Ptr);
+    // LDAPRB/H return i32 (zero-extended); truncate to match the declared type.
+    llvm::Type *RetTy = ConvertType(E->getType());
+    if (Result->getType() != RetTy)
+      Result = Builder.CreateTrunc(Result, RetTy);
+    return Result;
+  }
+
   if (BuiltinID == NEON::BI__builtin_neon_vcvth_bf16_f32)
     return Builder.CreateFPTrunc(
         Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)),
diff --git a/clang/lib/Headers/arm64intr.h b/clang/lib/Headers/arm64intr.h
index 3d6701cc78902..ea7d2109278bf 100644
--- a/clang/lib/Headers/arm64intr.h
+++ b/clang/lib/Headers/arm64intr.h
@@ -50,6 +50,11 @@ unsigned __int16 __ldar16(const volatile unsigned __int16 *);
 unsigned __int32 __ldar32(const volatile unsigned __int32 *);
 unsigned __int64 __ldar64(const volatile unsigned __int64 *);
 
+unsigned __int8 __ldapr8(const volatile unsigned __int8 *);
+unsigned __int16 __ldapr16(const volatile unsigned __int16 *);
+unsigned __int32 __ldapr32(const volatile unsigned __int32 *);
+unsigned __int64 __ldapr64(const volatile unsigned __int64 *);
+
 void __stlr8(unsigned __int8 volatile *, unsigned __int8);
 void __stlr16(unsigned __int16 volatile *, unsigned __int16);
 void __stlr32(unsigned __int32 volatile *, unsigned __int32);
diff --git a/clang/test/CodeGen/arm64-microsoft-intrinsics.c b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
index 2caf2c40b8a29..2d5c5f040f419 100644
--- a/clang/test/CodeGen/arm64-microsoft-intrinsics.c
+++ b/clang/test/CodeGen/arm64-microsoft-intrinsics.c
@@ -1297,6 +1297,43 @@ unsigned long long int test__swpal64(unsigned long long int volatile* t,
 // CHECK-MSCOMPAT:       ret i64 %[[RET]]
 // CHECK-LINUX: error: call to undeclared function '__swpal64'
 
+unsigned char check__ldapr8(unsigned char volatile *p) {
+  return __ldapr8(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i8 @check__ldapr8(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[LOAD:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMP:[0-9]+]] = call i32 @llvm.aarch64.ldapr8(ptr %[[LOAD]])
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = trunc i32 %[[TMP]] to i8
+// CHECK-MSCOMPAT:       ret i8 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldapr8'
+
+unsigned short check__ldapr16(unsigned short volatile *p) {
+  return __ldapr16(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i16 @check__ldapr16(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[LOAD:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[TMP:[0-9]+]] = call i32 @llvm.aarch64.ldapr16(ptr %[[LOAD]])
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = trunc i32 %[[TMP]] to i16
+// CHECK-MSCOMPAT:       ret i16 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldapr16'
+
+unsigned int check__ldapr32(unsigned int volatile *p) {
+  return __ldapr32(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i32 @check__ldapr32(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[LOAD:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i32 @llvm.aarch64.ldapr32(ptr %[[LOAD]])
+// CHECK-MSCOMPAT:       ret i32 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldapr32'
+
+unsigned long long int check__ldapr64(unsigned long long int volatile *p) {
+  return __ldapr64(p);
+}
+// CHECK-MSCOMPAT-LABEL: define{{.*}}i64 @check__ldapr64(ptr{{.*}}%p){{.*}}{
+// CHECK-MSCOMPAT:       %[[LOAD:[0-9]+]] = load ptr, ptr %p.addr, align 8
+// CHECK-MSCOMPAT:       %[[RET:[0-9]+]] = call i64 @llvm.aarch64.ldapr64(ptr %[[LOAD]])
+// CHECK-MSCOMPAT:       ret i64 %[[RET]]
+// CHECK-LINUX: error: call to undeclared function '__ldapr64'
 
 // CHECK-MSCOMPAT: ![[MD2]] = !{!"x18"}
 // CHECK-MSCOMPAT: ![[MD3]] = !{!"sp"}



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