[clang] [llvm] Remove __arm_atomic_store_with_stshh from llvm (PR #192419)

via cfe-commits cfe-commits at lists.llvm.org
Thu Apr 16 03:03:27 PDT 2026


https://github.com/Lukacma created https://github.com/llvm/llvm-project/pull/192419

Current implementation of __arm_atomic_store_with_stshh is incorrect as it doesn't enforce the memory ordering constraints as can be seen [here](https://godbolt.org/z/n5YnbaT8E). Different solution will need to be implemented, but removing for now so users don't pick this up. 

I have also added an auto upgrade for the intrinsic for the propriety sake.

>From 76ecc5bfdc4a53928c3fc55c3fcd50a0bda6e4b7 Mon Sep 17 00:00:00 2001
From: Marian Lukac <Marian.Lukac at arm.com>
Date: Thu, 16 Apr 2026 09:04:57 +0000
Subject: [PATCH 1/2] Remove pcdhint builtin

---
 clang/include/clang/Basic/BuiltinsAArch64.td  |   5 -
 .../clang/Basic/DiagnosticSemaKinds.td        |   8 -
 .../lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp  |   7 -
 clang/lib/CodeGen/TargetBuiltins/ARM.cpp      |  27 --
 clang/lib/Headers/arm_acle.h                  |   8 -
 clang/lib/Sema/SemaARM.cpp                    | 100 -------
 .../CodeGen/AArch64/pcdphint-atomic-store.c   |  71 -----
 clang/test/CodeGen/arm_acle.c                 |  11 -
 clang/test/CodeGen/builtins-arm64.c           |   5 -
 .../test/Sema/AArch64/pcdphint-atomic-store.c |  74 ------
 llvm/include/llvm/IR/IntrinsicsAArch64.td     |   6 -
 llvm/lib/IR/Verifier.cpp                      |  19 --
 .../AArch64/AArch64ExpandPseudoInsts.cpp      |  70 -----
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  13 -
 .../CodeGen/AArch64/pcdphint-atomic-store.ll  | 243 ------------------
 .../test/Verifier/AArch64/intrinsic-immarg.ll |  47 ----
 16 files changed, 714 deletions(-)
 delete mode 100644 clang/test/CodeGen/AArch64/pcdphint-atomic-store.c
 delete mode 100644 clang/test/Sema/AArch64/pcdphint-atomic-store.c
 delete mode 100644 llvm/test/CodeGen/AArch64/pcdphint-atomic-store.ll

diff --git a/clang/include/clang/Basic/BuiltinsAArch64.td b/clang/include/clang/Basic/BuiltinsAArch64.td
index 48ad4cb16f14c..8e5dbb5f4172d 100644
--- a/clang/include/clang/Basic/BuiltinsAArch64.td
+++ b/clang/include/clang/Basic/BuiltinsAArch64.td
@@ -171,11 +171,6 @@ let Attributes = [NoThrow], Features = "ls64" in {
 	def st64bv0 : AArch64TargetBuiltin<"uint64_t (void *, uint64_t const *)">;
 }
 
-// Atomic store with PCDPHINT
-let Attributes = [CustomTypeChecking] in {
-	def atomic_store_with_stshh : AArch64TargetBuiltin<"void (...)">;
-}
-
 // Armv9.3-A Guarded Control Stack
 let Attributes = [NoThrow], Features = "gcs" in {
 	def gcspopm : AArch64TargetBuiltin<"uint64_t (uint64_t)">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 4d352f1def04b..d051bb02c0af2 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9587,14 +9587,6 @@ def err_atomic_builtin_must_be_pointer_intfltptr : Error<
 def err_atomic_builtin_pointer_size : Error<
   "address argument to atomic builtin must be a pointer to 1,2,4,8 or 16 byte "
   "type (%0 invalid)">;
-def err_arm_atomic_store_with_stshh_bad_type : Error<
-  "address argument to '__arm_atomic_store_with_stshh' must be a pointer to an "
-  "8,16,32, or 64-bit integer type (%0 invalid)">;
-def err_arm_atomic_store_with_stshh_bad_value_type : Error<
-  "value argument to '__arm_atomic_store_with_stshh' must be %0; got %1">;
-def err_arm_atomic_store_with_stshh_bad_order : Error<
-  "memory order argument to '__arm_atomic_store_with_stshh' must be one of "
-  "__ATOMIC_RELAXED, __ATOMIC_RELEASE, or __ATOMIC_SEQ_CST">;
 def err_atomic_exclusive_builtin_pointer_size : Error<
   "address argument to load or store exclusive builtin must be a pointer to "
   // Because the range of legal sizes for load/store exclusive varies with the
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp
index d9d303cd07b92..45c5d3201f8e3 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinAArch64.cpp
@@ -1588,13 +1588,6 @@ CIRGenFunction::emitAArch64BuiltinExpr(unsigned builtinID, const CallExpr *expr,
     return mlir::Value{};
   }
 
-  if (builtinID == clang::AArch64::BI__builtin_arm_atomic_store_with_stshh) {
-    cgm.errorNYI(expr->getSourceRange(),
-                 std::string("unimplemented AArch64 builtin call: ") +
-                     getContext().BuiltinInfo.getName(builtinID));
-    return mlir::Value{};
-  }
-
   if (builtinID == clang::AArch64::BI__builtin_arm_rndr ||
       builtinID == clang::AArch64::BI__builtin_arm_rndrrs) {
     cgm.errorNYI(expr->getSourceRange(),
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
index 8ec2f5b83085c..17c811221a702 100644
--- a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -4673,33 +4673,6 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Builder.CreateCall(F, Args);
   }
 
-  if (BuiltinID == clang::AArch64::BI__builtin_arm_atomic_store_with_stshh) {
-    Value *StoreAddr = EmitScalarExpr(E->getArg(0));
-    Value *StoreValue = EmitScalarExpr(E->getArg(1));
-
-    auto *OrderC = cast<ConstantInt>(EmitScalarExpr(E->getArg(2)));
-    auto *PolicyC = cast<ConstantInt>(EmitScalarExpr(E->getArg(3)));
-
-    // Compute pointee bit-width from arg0 and create as i32 constant
-    QualType ValQT =
-        E->getArg(0)->getType()->castAs<PointerType>()->getPointeeType();
-    unsigned SizeBits = getContext().getTypeSize(ValQT);
-    auto *SizeC = llvm::ConstantInt::get(Int32Ty, SizeBits);
-
-    Value *StoreValue64 = Builder.CreateIntCast(StoreValue, Int64Ty,
-                                                ValQT->isSignedIntegerType());
-
-    Function *F = CGM.getIntrinsic(Intrinsic::aarch64_stshh_atomic_store,
-                                   {StoreAddr->getType()});
-
-    // Emit a single intrinsic so backend can expand to STSHH followed by
-    // atomic store, to guarantee STSHH immediately precedes STR insn
-    return Builder.CreateCall(
-        F, {StoreAddr, StoreValue64,
-            ConstantInt::get(Int32Ty, OrderC->getZExtValue()),
-            ConstantInt::get(Int32Ty, PolicyC->getZExtValue()), SizeC});
-  }
-
   if (BuiltinID == clang::AArch64::BI__builtin_arm_rndr ||
       BuiltinID == clang::AArch64::BI__builtin_arm_rndrrs) {
 
diff --git a/clang/lib/Headers/arm_acle.h b/clang/lib/Headers/arm_acle.h
index 929c88cf72ef2..9a6b6a837fa5a 100644
--- a/clang/lib/Headers/arm_acle.h
+++ b/clang/lib/Headers/arm_acle.h
@@ -840,14 +840,6 @@ __rndrrs(uint64_t *__p) {
 }
 #endif
 
-/* Atomic store with PCDPHINT */
-#if defined(__ARM_64BIT_STATE) && __ARM_64BIT_STATE
-#define __arm_atomic_store_with_stshh(ptr, data, memory_order,                 \
-                                      retention_policy)                        \
-  __builtin_arm_atomic_store_with_stshh(ptr, data, memory_order,               \
-                                        retention_policy)
-#endif
-
 /* 11.2 Guarded Control Stack intrinsics */
 #if defined(__ARM_64BIT_STATE) && __ARM_64BIT_STATE
 static __inline__ void * __attribute__((__always_inline__, __nodebug__))
diff --git a/clang/lib/Sema/SemaARM.cpp b/clang/lib/Sema/SemaARM.cpp
index e54c8228e5ff8..29cf6fcd5be7e 100644
--- a/clang/lib/Sema/SemaARM.cpp
+++ b/clang/lib/Sema/SemaARM.cpp
@@ -1107,103 +1107,6 @@ bool SemaARM::CheckARMBuiltinFunctionCall(const TargetInfo &TI,
   }
 }
 
-static bool CheckAArch64AtomicStoreWithStshhCall(SemaARM &S,
-                                                 CallExpr *TheCall) {
-  Sema &SemaRef = S.SemaRef;
-  ASTContext &Context = S.getASTContext();
-  // Ensure we have the proper number of arguments.
-  if (SemaRef.checkArgCount(TheCall, 4))
-    return true;
-
-  // Normalize arg0/arg1 into value form, and check valid
-  ExprResult PtrRes =
-      SemaRef.DefaultFunctionArrayLvalueConversion(TheCall->getArg(0));
-  ExprResult ValRes =
-      SemaRef.DefaultFunctionArrayLvalueConversion(TheCall->getArg(1));
-
-  if (PtrRes.isInvalid() || ValRes.isInvalid())
-    return true;
-
-  Expr *OrderArg = TheCall->getArg(2);
-  TheCall->setArg(0, PtrRes.get());
-  TheCall->setArg(1, ValRes.get());
-
-  // Defer validation for dependent memory_order arguments.
-  if (OrderArg->isValueDependent())
-    return false;
-
-  Expr *PointerArg = PtrRes.get();
-  QualType PtrType = PointerArg->getType();
-
-  // Check arg 0 is a pointer type, err out if not
-  const PointerType *PointerTy = PtrType->getAs<PointerType>();
-  if (!PointerTy) {
-    SemaRef.Diag(PointerArg->getBeginLoc(),
-                 diag::err_atomic_builtin_must_be_pointer)
-        << PtrType << 0 << PointerArg->getSourceRange();
-    return true;
-  }
-
-  // Reject const-qualified pointee types
-  QualType ValType = PointerTy->getPointeeType();
-  if (ValType.isConstQualified()) {
-    SemaRef.Diag(PointerArg->getBeginLoc(),
-                 diag::err_atomic_builtin_cannot_be_const)
-        << PtrType << PointerArg->getSourceRange();
-    return true;
-  }
-
-  ValType = ValType.getUnqualifiedType();
-  unsigned Bits = ValType->isIntegerType() ? Context.getTypeSize(ValType) : 0;
-  if (Bits != 8 && Bits != 16 && Bits != 32 && Bits != 64) {
-    SemaRef.Diag(PointerArg->getBeginLoc(),
-                 diag::err_arm_atomic_store_with_stshh_bad_type)
-        << PtrType << PointerArg->getSourceRange();
-    return true;
-  }
-
-  Expr *ValArg = TheCall->getArg(1);
-  QualType ValArgType = ValArg->getType().getUnqualifiedType();
-
-  // Check value type and width
-  if (!Context.hasSameType(ValArgType, ValType)) {
-    SemaRef.Diag(ValArg->getBeginLoc(),
-                 diag::err_arm_atomic_store_with_stshh_bad_value_type)
-        << ValType << ValArg->getType() << ValArg->getSourceRange();
-    return true;
-  }
-
-  // Require an order value.
-  std::optional<llvm::APSInt> OrderValOpt =
-      OrderArg->getIntegerConstantExpr(Context);
-  if (!OrderValOpt) {
-    SemaRef.Diag(OrderArg->getBeginLoc(),
-                 diag::err_arm_atomic_store_with_stshh_bad_order)
-        << OrderArg->getSourceRange();
-    return true;
-  }
-
-  // __ATOMIC_RELAXED=0, __ATOMIC_RELEASE=3, __ATOMIC_SEQ_CST=5.
-  int64_t Order = OrderValOpt->getSExtValue();
-  if (Order != 0 && Order != 3 && Order != 5) {
-    SemaRef.Diag(OrderArg->getBeginLoc(),
-                 diag::err_arm_atomic_store_with_stshh_bad_order)
-        << OrderArg->getSourceRange();
-    return true;
-  }
-
-  // Value type already matches ValType above; apply a no-op cast for
-  // consistency with other builtin argument rewriting paths.
-  ExprResult ValArgRes = SemaRef.ImpCastExprToType(ValArg, ValType, CK_NoOp);
-  if (ValArgRes.isInvalid())
-    return true;
-
-  TheCall->setArg(1, ValArgRes.get());
-
-  // Arg 3 (retention policy) must be between KEEP(0) and STRM(1).
-  return SemaRef.BuiltinConstantArgRange(TheCall, 3, 0, 1);
-}
-
 bool SemaARM::CheckAArch64BuiltinFunctionCall(const TargetInfo &TI,
                                               unsigned BuiltinID,
                                               CallExpr *TheCall) {
@@ -1214,9 +1117,6 @@ bool SemaARM::CheckAArch64BuiltinFunctionCall(const TargetInfo &TI,
     return CheckARMBuiltinExclusiveCall(TI, BuiltinID, TheCall);
   }
 
-  if (BuiltinID == AArch64::BI__builtin_arm_atomic_store_with_stshh)
-    return CheckAArch64AtomicStoreWithStshhCall(*this, TheCall);
-
   if (BuiltinID == AArch64::BI__builtin_arm_prefetch) {
     return SemaRef.BuiltinConstantArgRange(TheCall, 1, 0, 1) ||
            SemaRef.BuiltinConstantArgRange(TheCall, 2, 0, 3) ||
diff --git a/clang/test/CodeGen/AArch64/pcdphint-atomic-store.c b/clang/test/CodeGen/AArch64/pcdphint-atomic-store.c
deleted file mode 100644
index f48f1d6344bc5..0000000000000
--- a/clang/test/CodeGen/AArch64/pcdphint-atomic-store.c
+++ /dev/null
@@ -1,71 +0,0 @@
-// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
-// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -emit-llvm -o - %s | FileCheck %s
-
-#include <arm_acle.h>
-
-// CHECK-LABEL: define dso_local void @test_u8(
-// CHECK-SAME: ptr noundef [[P:%.*]], i8 noundef [[V:%.*]]) #[[ATTR0:[0-9]+]] {
-// CHECK-NEXT:  [[ENTRY:.*:]]
-// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca i8, align 1
-// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    store i8 [[V]], ptr [[V_ADDR]], align 1
-// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    [[TMP1:%.*]] = load i8, ptr [[V_ADDR]], align 1
-// CHECK-NEXT:    [[TMP2:%.*]] = zext i8 [[TMP1]] to i64
-// CHECK-NEXT:    call void @llvm.aarch64.stshh.atomic.store.p0(ptr [[TMP0]], i64 [[TMP2]], i32 0, i32 0, i32 8)
-// CHECK-NEXT:    ret void
-//
-void test_u8(unsigned char *p, unsigned char v) {
-  __arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-}
-
-// CHECK-LABEL: define dso_local void @test_u16(
-// CHECK-SAME: ptr noundef [[P:%.*]], i16 noundef [[V:%.*]]) #[[ATTR0]] {
-// CHECK-NEXT:  [[ENTRY:.*:]]
-// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca i16, align 2
-// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    store i16 [[V]], ptr [[V_ADDR]], align 2
-// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    [[TMP1:%.*]] = load i16, ptr [[V_ADDR]], align 2
-// CHECK-NEXT:    [[TMP2:%.*]] = zext i16 [[TMP1]] to i64
-// CHECK-NEXT:    call void @llvm.aarch64.stshh.atomic.store.p0(ptr [[TMP0]], i64 [[TMP2]], i32 3, i32 1, i32 16)
-// CHECK-NEXT:    ret void
-//
-void test_u16(unsigned short *p, unsigned short v) {
-  __arm_atomic_store_with_stshh(p, v, __ATOMIC_RELEASE, 1);
-}
-
-// CHECK-LABEL: define dso_local void @test_u32(
-// CHECK-SAME: ptr noundef [[P:%.*]], i32 noundef [[V:%.*]]) #[[ATTR0]] {
-// CHECK-NEXT:  [[ENTRY:.*:]]
-// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca i32, align 4
-// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    store i32 [[V]], ptr [[V_ADDR]], align 4
-// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr [[V_ADDR]], align 4
-// CHECK-NEXT:    [[TMP2:%.*]] = zext i32 [[TMP1]] to i64
-// CHECK-NEXT:    call void @llvm.aarch64.stshh.atomic.store.p0(ptr [[TMP0]], i64 [[TMP2]], i32 5, i32 0, i32 32)
-// CHECK-NEXT:    ret void
-//
-void test_u32(unsigned int *p, unsigned int v) {
-  __arm_atomic_store_with_stshh(p, v, __ATOMIC_SEQ_CST, 0);
-}
-
-// CHECK-LABEL: define dso_local void @test_u64(
-// CHECK-SAME: ptr noundef [[P:%.*]], i64 noundef [[V:%.*]]) #[[ATTR0]] {
-// CHECK-NEXT:  [[ENTRY:.*:]]
-// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8
-// CHECK-NEXT:    [[V_ADDR:%.*]] = alloca i64, align 8
-// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    store i64 [[V]], ptr [[V_ADDR]], align 8
-// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
-// CHECK-NEXT:    [[TMP1:%.*]] = load i64, ptr [[V_ADDR]], align 8
-// CHECK-NEXT:    call void @llvm.aarch64.stshh.atomic.store.p0(ptr [[TMP0]], i64 [[TMP1]], i32 0, i32 1, i32 64)
-// CHECK-NEXT:    ret void
-//
-void test_u64(unsigned long *p, unsigned long v) {
-  __arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 1);
-}
diff --git a/clang/test/CodeGen/arm_acle.c b/clang/test/CodeGen/arm_acle.c
index 3b97f90e806fc..cd18fa63bfdbd 100644
--- a/clang/test/CodeGen/arm_acle.c
+++ b/clang/test/CodeGen/arm_acle.c
@@ -1821,14 +1821,3 @@ int test_rndrrs(uint64_t *__addr) {
   return __rndrrs(__addr);
 }
 #endif
-
-#if defined(__ARM_64BIT_STATE)
-// AArch64-LABEL: @test_stshh_atomic_store(
-// AArch64-NEXT:  entry:
-// AArch64:         call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 {{.*}}, i32 0, i32 0, i32 32)
-// AArch64-NEXT:    ret void
-//
-void test_stshh_atomic_store(int *p, int v) {
-  __arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-}
-#endif
diff --git a/clang/test/CodeGen/builtins-arm64.c b/clang/test/CodeGen/builtins-arm64.c
index 5344a2c5c6c5b..3d054c79f1777 100644
--- a/clang/test/CodeGen/builtins-arm64.c
+++ b/clang/test/CodeGen/builtins-arm64.c
@@ -39,11 +39,6 @@ void hints(void) {
   __builtin_arm_sevl();   //CHECK: call {{.*}} @llvm.aarch64.hint(i32 5)
 }
 
-void stshh_atomic_store(int *p, int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // CHECK: call void @llvm.aarch64.stshh.atomic.store.p0(ptr {{.*}}, i64 {{.*}}, i32 0, i32 0, i32 32)
-}
-
 void barriers(void) {
   __builtin_arm_dmb(1);  //CHECK: call {{.*}} @llvm.aarch64.dmb(i32 1)
   __builtin_arm_dsb(2);  //CHECK: call {{.*}} @llvm.aarch64.dsb(i32 2)
diff --git a/clang/test/Sema/AArch64/pcdphint-atomic-store.c b/clang/test/Sema/AArch64/pcdphint-atomic-store.c
deleted file mode 100644
index 5b4bf27003a5a..0000000000000
--- a/clang/test/Sema/AArch64/pcdphint-atomic-store.c
+++ /dev/null
@@ -1,74 +0,0 @@
-// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -fsyntax-only -verify %s
-// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -emit-llvm -o /dev/null -verify %s
-
-#include <arm_acle.h>
-
-void test_signed_ok(int *p, int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-}
-
-void test_invalid_retention_policy(unsigned int *p, unsigned int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 2);
-  // expected-error at -1 {{argument value 2 is outside the valid range [0, 1]}}
-}
-
-void test_const_pointer(const unsigned int *p, unsigned int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{address argument to atomic builtin cannot be const-qualified}}
-}
-
-void test_non_integer_pointer(float *p, float v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{address argument to '__arm_atomic_store_with_stshh' must be a pointer to an 8,16,32, or 64-bit integer type}}
-}
-
-void test_invalid_bit_width(__int128 *p, __int128 v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{address argument to '__arm_atomic_store_with_stshh' must be a pointer to an 8,16,32, or 64-bit integer type}}
-}
-
-struct IncompleteType;
-void test_incomplete_pointee(struct IncompleteType *p, int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{address argument to '__arm_atomic_store_with_stshh' must be a pointer to an 8,16,32, or 64-bit integer type}}
-}
-
-void test_invalid_memory_order(unsigned int *p, unsigned int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_ACQUIRE, 0);
-  // expected-error at -1 {{memory order argument to '__arm_atomic_store_with_stshh' must be one of __ATOMIC_RELAXED, __ATOMIC_RELEASE, or __ATOMIC_SEQ_CST}}
-}
-
-void test_invalid_memory_order_consume(unsigned int *p, unsigned int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_CONSUME, 0);
-  // expected-error at -1 {{memory order argument to '__arm_atomic_store_with_stshh' must be one of __ATOMIC_RELAXED, __ATOMIC_RELEASE, or __ATOMIC_SEQ_CST}}
-}
-
-void test_invalid_memory_order_acq_rel(unsigned int *p, unsigned int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_ACQ_REL, 0);
-  // expected-error at -1 {{memory order argument to '__arm_atomic_store_with_stshh' must be one of __ATOMIC_RELAXED, __ATOMIC_RELEASE, or __ATOMIC_SEQ_CST}}
-}
-
-void test_value_size_mismatch(int *p, short v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{value argument to '__arm_atomic_store_with_stshh' must be 'int'; got 'short'}}
-}
-
-void test_non_integer_value(int *p, float v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{value argument to '__arm_atomic_store_with_stshh' must be 'int'; got 'float'}}
-}
-
-void test_too_few_args(int *p, int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED);
-  // expected-error at -1 {{too few arguments to function call, expected 4, have 3}}
-}
-
-void test_too_many_args(int *p, int v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0, 1);
-  // expected-error at -1 {{too many arguments to function call, expected 4, have 5}}
-}
-
-void test_value_i128_mismatch(int *p, __int128 v) {
-  __builtin_arm_atomic_store_with_stshh(p, v, __ATOMIC_RELAXED, 0);
-  // expected-error at -1 {{value argument to '__arm_atomic_store_with_stshh' must be 'int'; got '__int128'}}
-}
diff --git a/llvm/include/llvm/IR/IntrinsicsAArch64.td b/llvm/include/llvm/IR/IntrinsicsAArch64.td
index 63500beaa6521..2660d79db4313 100644
--- a/llvm/include/llvm/IR/IntrinsicsAArch64.td
+++ b/llvm/include/llvm/IR/IntrinsicsAArch64.td
@@ -65,12 +65,6 @@ def int_aarch64_sys  : DefaultAttrsIntrinsic<[], [llvm_i32_ty, llvm_i32_ty,
 // HINT
 
 def int_aarch64_hint : DefaultAttrsIntrinsic<[], [llvm_i32_ty]>;
-def int_aarch64_stshh_atomic_store
-    : Intrinsic<[],
-                [llvm_anyptr_ty, llvm_i64_ty, llvm_i32_ty, llvm_i32_ty,
-                 llvm_i32_ty],
-                [IntrHasSideEffects, ImmArg<ArgIndex<2>>,
-                 ImmArg<ArgIndex<3>>, ImmArg<ArgIndex<4>>]>;
 
 def int_aarch64_break : Intrinsic<[], [llvm_i32_ty],
     [IntrNoMem, IntrHasSideEffects, IntrNoReturn, IntrCold, ImmArg<ArgIndex<0>>]>;
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 5909738b0c903..672e689e6a064 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -6901,25 +6901,6 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
           Call);
     break;
   }
-  case Intrinsic::aarch64_stshh_atomic_store: {
-    uint64_t Order = cast<ConstantInt>(Call.getArgOperand(2))->getZExtValue();
-    Check(Order == static_cast<uint64_t>(AtomicOrderingCABI::relaxed) ||
-              Order == static_cast<uint64_t>(AtomicOrderingCABI::release) ||
-              Order == static_cast<uint64_t>(AtomicOrderingCABI::seq_cst),
-          "order argument to llvm.aarch64.stshh.atomic.store must be 0, 3 or 5",
-          Call);
-
-    Check(cast<ConstantInt>(Call.getArgOperand(3))->getZExtValue() < 2,
-          "policy argument to llvm.aarch64.stshh.atomic.store must be 0 or 1",
-          Call);
-
-    uint64_t Size = cast<ConstantInt>(Call.getArgOperand(4))->getZExtValue();
-    Check(Size == 8 || Size == 16 || Size == 32 || Size == 64,
-          "size argument to llvm.aarch64.stshh.atomic.store must be 8, 16, "
-          "32 or 64",
-          Call);
-    break;
-  }
   case Intrinsic::callbr_landingpad: {
     const auto *CBR = dyn_cast<CallBrInst>(Call.getOperand(0));
     Check(CBR, "intrinstic requires callbr operand", &Call);
diff --git a/llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp b/llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
index 4ab8adeb2c9bc..bd386f05501b1 100644
--- a/llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
@@ -26,7 +26,6 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
-#include "llvm/CodeGen/MachineInstrBundle.h"
 #include "llvm/CodeGen/MachineOperand.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/DebugLoc.h"
@@ -89,8 +88,6 @@ class AArch64ExpandPseudoImpl {
   bool expandCALL_BTI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
   bool expandStoreSwiftAsyncContext(MachineBasicBlock &MBB,
                                     MachineBasicBlock::iterator MBBI);
-  bool expandSTSHHAtomicStore(MachineBasicBlock &MBB,
-                              MachineBasicBlock::iterator MBBI);
   struct ConditionalBlocks {
     MachineBasicBlock &CondBB;
     MachineBasicBlock &EndBB;
@@ -1061,71 +1058,6 @@ bool AArch64ExpandPseudoImpl::expandStoreSwiftAsyncContext(
   return true;
 }
 
-bool AArch64ExpandPseudoImpl::expandSTSHHAtomicStore(
-    MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI) {
-  MachineInstr &MI = *MBBI;
-  DebugLoc DL(MI.getDebugLoc());
-
-  unsigned Order = MI.getOperand(2).getImm();
-  unsigned Policy = MI.getOperand(3).getImm();
-  unsigned Size = MI.getOperand(4).getImm();
-
-  bool IsRelaxed = Order == 0;
-  unsigned StoreOpc = 0;
-
-  // __ATOMIC_RELAXED uses STR. __ATOMIC_{RELEASE/SEQ_CST} use STLR.
-  switch (Size) {
-  case 8:
-    StoreOpc = IsRelaxed ? AArch64::STRBBui : AArch64::STLRB;
-    break;
-  case 16:
-    StoreOpc = IsRelaxed ? AArch64::STRHHui : AArch64::STLRH;
-    break;
-  case 32:
-    StoreOpc = IsRelaxed ? AArch64::STRWui : AArch64::STLRW;
-    break;
-  case 64:
-    StoreOpc = IsRelaxed ? AArch64::STRXui : AArch64::STLRX;
-    break;
-  default:
-    llvm_unreachable("Unexpected STSHH atomic store size");
-  }
-
-  // Emit the hint with the retention policy immediate.
-  MachineInstr *Hint = BuildMI(MBB, MBBI, DL, TII->get(AArch64::STSHH))
-                           .addImm(Policy)
-                           .getInstr();
-
-  // Emit the associated store instruction.
-  Register ValReg = MI.getOperand(0).getReg();
-
-  if (Size < 64) {
-    const TargetRegisterInfo *TRI =
-        MBB.getParent()->getSubtarget().getRegisterInfo();
-    Register SubReg = TRI->getSubReg(ValReg, AArch64::sub_32);
-    if (SubReg)
-      ValReg = SubReg;
-  }
-
-  MachineInstrBuilder Store = BuildMI(MBB, MBBI, DL, TII->get(StoreOpc))
-                                  .addReg(ValReg)
-                                  .add(MI.getOperand(1));
-
-  // Relaxed uses base+imm addressing with a zero offset.
-  if (IsRelaxed)
-    Store.addImm(0);
-
-  // Preserve memory operands and any implicit uses/defs.
-  Store->setMemRefs(*MBB.getParent(), MI.memoperands());
-  transferImpOps(MI, Store, Store);
-
-  // Bundle the hint and store so they remain adjacent.
-  finalizeBundle(MBB, Hint->getIterator(), std::next(Store->getIterator()));
-
-  MI.eraseFromParent();
-  return true;
-}
-
 AArch64ExpandPseudoImpl::ConditionalBlocks
 AArch64ExpandPseudoImpl::expandConditionalPseudo(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, DebugLoc DL,
@@ -1820,8 +1752,6 @@ bool AArch64ExpandPseudoImpl::expandMI(MachineBasicBlock &MBB,
     return expandCALL_BTI(MBB, MBBI);
   case AArch64::StoreSwiftAsyncContext:
     return expandStoreSwiftAsyncContext(MBB, MBBI);
-  case AArch64::STSHH_ATOMIC_STORE_SZ:
-    return expandSTSHHAtomicStore(MBB, MBBI);
   case AArch64::RestoreZAPseudo:
   case AArch64::CommitZASavePseudo:
   case AArch64::MSRpstatePseudo: {
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 08512f6ed8df1..268bb031c0dab 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -1568,19 +1568,6 @@ def : InstAlias<"nop", (NOP)>;
 
 def STSHH: STSHHI;
 
-let hasSideEffects = 1, mayStore = 1, isCodeGenOnly = 1 in {
-let Size = 8 in
-def STSHH_ATOMIC_STORE_SZ
-    : Pseudo<(outs), (ins GPR64:$val, GPR64sp:$addr, i32imm:$order,
-                          i32imm:$policy, i32imm:$size), []>,
-             Sched<[WriteAtomic]>;
-}
-
-def : Pat<(int_aarch64_stshh_atomic_store GPR64sp:$addr, GPR64:$val,
-           (i32 timm:$order), (i32 timm:$policy), (i32 timm:$size)),
-          (STSHH_ATOMIC_STORE_SZ GPR64:$val, GPR64sp:$addr, (i32 timm:$order),
-           (i32 timm:$policy), (i32 timm:$size))>;
-
 // In order to be able to write readable assembly, LLVM should accept assembly
 // inputs that use Branch Target Identification mnemonics, even with BTI disabled.
 // However, in order to be compatible with other assemblers (e.g. GAS), LLVM
diff --git a/llvm/test/CodeGen/AArch64/pcdphint-atomic-store.ll b/llvm/test/CodeGen/AArch64/pcdphint-atomic-store.ll
deleted file mode 100644
index 6e48cb348ca05..0000000000000
--- a/llvm/test/CodeGen/AArch64/pcdphint-atomic-store.ll
+++ /dev/null
@@ -1,243 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
-; RUN: llc -mtriple=aarch64 -mattr=+v9.6a < %s | FileCheck %s
-; RUN: llc -mtriple=aarch64 -mattr=+v9.6a -global-isel=1 < %s | FileCheck %s
-
-define void @test_keep_relaxed_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_relaxed_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    strb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 8)
-  ret void
-}
-
-define void @test_keep_relaxed_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_relaxed_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    strh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 16)
-  ret void
-}
-
-define void @test_keep_relaxed_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_relaxed_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    str w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 32)
-  ret void
-}
-
-define void @test_keep_relaxed_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_relaxed_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    str x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 64)
-  ret void
-}
-
-define void @test_keep_release_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_release_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlrb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 0, i32 8)
-  ret void
-}
-
-define void @test_keep_release_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_release_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlrh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 0, i32 16)
-  ret void
-}
-
-define void @test_keep_release_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_release_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlr w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 0, i32 32)
-  ret void
-}
-
-define void @test_keep_release_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_release_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlr x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 0, i32 64)
-  ret void
-}
-
-define void @test_keep_seqcst_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_seqcst_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlrb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 0, i32 8)
-  ret void
-}
-
-define void @test_keep_seqcst_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_seqcst_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlrh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 0, i32 16)
-  ret void
-}
-
-define void @test_keep_seqcst_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_seqcst_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlr w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 0, i32 32)
-  ret void
-}
-
-define void @test_keep_seqcst_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_keep_seqcst_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh keep
-; CHECK-NEXT:    stlr x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 0, i32 64)
-  ret void
-}
-
-define void @test_strm_relaxed_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_relaxed_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    strb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 1, i32 8)
-  ret void
-}
-
-define void @test_strm_relaxed_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_relaxed_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    strh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 1, i32 16)
-  ret void
-}
-
-define void @test_strm_relaxed_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_relaxed_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    str w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 1, i32 32)
-  ret void
-}
-
-define void @test_strm_relaxed_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_relaxed_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    str x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 1, i32 64)
-  ret void
-}
-
-define void @test_strm_release_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_release_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlrb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 1, i32 8)
-  ret void
-}
-
-define void @test_strm_release_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_release_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlrh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 1, i32 16)
-  ret void
-}
-
-define void @test_strm_release_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_release_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlr w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 1, i32 32)
-  ret void
-}
-
-define void @test_strm_release_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_release_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlr x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 1, i32 64)
-  ret void
-}
-
-define void @test_strm_seqcst_i8(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_seqcst_i8:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlrb w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 1, i32 8)
-  ret void
-}
-
-define void @test_strm_seqcst_i16(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_seqcst_i16:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlrh w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 1, i32 16)
-  ret void
-}
-
-define void @test_strm_seqcst_i32(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_seqcst_i32:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlr w1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 1, i32 32)
-  ret void
-}
-
-define void @test_strm_seqcst_i64(ptr %p, i64 %v) {
-; CHECK-LABEL: test_strm_seqcst_i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    stshh strm
-; CHECK-NEXT:    stlr x1, [x0]
-; CHECK-NEXT:    ret
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 1, i32 64)
-  ret void
-}
diff --git a/llvm/test/Verifier/AArch64/intrinsic-immarg.ll b/llvm/test/Verifier/AArch64/intrinsic-immarg.ll
index cd702f18cd709..e17c11d66dac4 100644
--- a/llvm/test/Verifier/AArch64/intrinsic-immarg.ll
+++ b/llvm/test/Verifier/AArch64/intrinsic-immarg.ll
@@ -11,50 +11,3 @@ define void @range_prefetch(ptr %src, i64 %metadata) {
 
   ret void
 }
-
-declare void @llvm.aarch64.stshh.atomic.store.p0(ptr, i64, i32 immarg, i32 immarg, i32 immarg)
-
-define void @stshh_atomic_store_order_non_imm(ptr %p, i64 %v, i32 %arg0) {
-  ; CHECK: immarg operand has non-immediate parameter
-  ; CHECK-NEXT: i32 %arg0
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 %arg0, i32 0, i32 64)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 %arg0, i32 0, i32 64)
-  ret void
-}
-
-define void @stshh_atomic_store_policy_non_imm(ptr %p, i64 %v, i32 %arg0) {
-  ; CHECK: immarg operand has non-immediate parameter
-  ; CHECK-NEXT: i32 %arg0
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 %arg0, i32 64)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 %arg0, i32 64)
-  ret void
-}
-
-define void @stshh_atomic_store_size_non_imm(ptr %p, i64 %v, i32 %arg0) {
-  ; CHECK: immarg operand has non-immediate parameter
-  ; CHECK-NEXT: i32 %arg0
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 %arg0)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 %arg0)
-  ret void
-}
-
-define void @stshh_atomic_store_order_out_of_range(ptr %p, i64 %v) {
-  ; CHECK: order argument to llvm.aarch64.stshh.atomic.store must be 0, 3 or 5
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 1, i32 0, i32 64)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 1, i32 0, i32 64)
-  ret void
-}
-
-define void @stshh_atomic_store_policy_out_of_range(ptr %p, i64 %v) {
-  ; CHECK: policy argument to llvm.aarch64.stshh.atomic.store must be 0 or 1
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 2, i32 64)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 2, i32 64)
-  ret void
-}
-
-define void @stshh_atomic_store_size_out_of_range(ptr %p, i64 %v) {
-  ; CHECK: size argument to llvm.aarch64.stshh.atomic.store must be 8, 16, 32 or 64
-  ; CHECK-NEXT: call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 0)
-  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 0, i32 0)
-  ret void
-}

>From 81db02f2bff4786ccaf3d9ca0e481e11be1f46b6 Mon Sep 17 00:00:00 2001
From: Marian Lukac <Marian.Lukac at arm.com>
Date: Thu, 16 Apr 2026 09:54:19 +0000
Subject: [PATCH 2/2] Autoupgrade stshh intrinsic store node

---
 llvm/lib/IR/AutoUpgrade.cpp                   | 31 +++++++++++++++++++
 .../autoupgrade-aarch64-stshh-atomic-store.ll | 27 ++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 llvm/test/Assembler/autoupgrade-aarch64-stshh-atomic-store.ll

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index d336966c272f9..98e4ad74ab7f8 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -45,6 +45,7 @@
 #include "llvm/IR/Value.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/AMDGPUAddrSpace.h"
+#include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/NVPTXAddrSpace.h"
@@ -1100,6 +1101,11 @@ static bool upgradeArmOrAarch64IntrinsicFunction(bool IsArm, Function *F,
 
       return false; // No other 'aarch64.sve.*'.
     }
+
+    if (Name.starts_with("stshh.atomic.store")) {
+      NewFn = nullptr;
+      return true;
+    }
   }
   return false; // No other 'arm.*', 'aarch64.*'.
 }
@@ -4585,6 +4591,31 @@ static Value *upgradeAArch64IntrinsicCall(StringRef Name, CallBase *CI,
 
     return Builder.CreateIntrinsic(NewID, Args, /*FMFSource=*/nullptr,
                                    CI->getName());
+  } else if (Name.starts_with("stshh.atomic.store")) {
+    uint64_t OrderArg = cast<ConstantInt>(CI->getArgOperand(2))->getZExtValue();
+    uint64_t SizeArg = cast<ConstantInt>(CI->getArgOperand(4))->getZExtValue();
+
+    AtomicOrdering Order;
+    switch (AtomicOrderingCABI(OrderArg)) {
+    case AtomicOrderingCABI::relaxed:
+      Order = AtomicOrdering::Monotonic;
+      break;
+    case AtomicOrderingCABI::release:
+      Order = AtomicOrdering::Release;
+      break;
+    case AtomicOrderingCABI::seq_cst:
+      Order = AtomicOrdering::SequentiallyConsistent;
+      break;
+    default:
+      reportFatalUsageErrorWithCI("Intrinsic has invalid atomic ordering", CI);
+    }
+
+    Type *StoreTy = Builder.getIntNTy(SizeArg);
+    Value *StoreVal = Builder.CreateTrunc(CI->getArgOperand(1), StoreTy);
+    auto *SI = Builder.CreateAlignedStore(StoreVal, CI->getArgOperand(0),
+                                          Align(SizeArg / 8));
+    SI->setAtomic(Order);
+    return nullptr;
   }
 
   llvm_unreachable("Unhandled Intrinsic!");
diff --git a/llvm/test/Assembler/autoupgrade-aarch64-stshh-atomic-store.ll b/llvm/test/Assembler/autoupgrade-aarch64-stshh-atomic-store.ll
new file mode 100644
index 0000000000000..51e11cfe09b54
--- /dev/null
+++ b/llvm/test/Assembler/autoupgrade-aarch64-stshh-atomic-store.ll
@@ -0,0 +1,27 @@
+; Test autoupgrade of the removed llvm.aarch64.stshh.atomic.store intrinsic.
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+declare void @llvm.aarch64.stshh.atomic.store.p0(ptr, i64, i32 immarg, i32 immarg, i32 immarg)
+
+define void @relaxed_i8(ptr %p, i64 %v) {
+; CHECK-LABEL: define void @relaxed_i8(
+; CHECK: %[[TRUNC:.+]] = trunc i64 %v to i8
+; CHECK-NEXT: store atomic i8 %[[TRUNC]], ptr %p monotonic, align 1
+  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 0, i32 1, i32 8)
+  ret void
+}
+
+define void @release_i32(ptr %p, i64 %v) {
+; CHECK-LABEL: define void @release_i32(
+; CHECK: %[[TRUNC:.+]] = trunc i64 %v to i32
+; CHECK-NEXT: store atomic i32 %[[TRUNC]], ptr %p release, align 4
+  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 3, i32 0, i32 32)
+  ret void
+}
+
+define void @seq_cst_i64(ptr %p, i64 %v) {
+; CHECK-LABEL: define void @seq_cst_i64(
+; CHECK: store atomic i64 %v, ptr %p seq_cst, align 8
+  call void @llvm.aarch64.stshh.atomic.store.p0(ptr %p, i64 %v, i32 5, i32 1, i32 64)
+  ret void
+}



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