[clang] [Clang][AMDGPU] Add ``amdgcn_av("none")`` attribute for atomic expressions (PR #199622)

Sameer Sahasrabuddhe via cfe-commits cfe-commits at lists.llvm.org
Thu Jul 30 03:23:43 PDT 2026


https://github.com/ssahasra updated https://github.com/llvm/llvm-project/pull/199622

>From 21c30bc99dac05a432dda1502b0b9f3e3ef1d6e3 Mon Sep 17 00:00:00 2001
From: Sameer Sahasrabuddhe <sameer.sahasrabuddhe at amd.com>
Date: Tue, 7 Jul 2026 19:57:07 +0530
Subject: [PATCH] [Clang][AMDGPU] Add amdgpu_av("none") attribute for atomic
 expressions

Add a statement attribute that suppresses MakeAvailable/MakeVisible
cache operations on AMDGPU atomic instructions while preserving memory
ordering (waits).

The attribute takes a string argument specifying the mode. Currently "none" is
the only supported mode. The resulting atomic or fence instruction carries !mmra
!{!"amdgcn-av", !"none"} metadata.

Assisted-By: Claude Opus 4.6
---
 clang/include/clang/Basic/Attr.td             |   6 +
 clang/include/clang/Basic/AttrDocs.td         |  26 ++++
 clang/include/clang/Basic/DiagnosticGroups.td |   2 +
 .../clang/Basic/DiagnosticSemaKinds.td        |   7 +
 clang/lib/CodeGen/CGAtomic.cpp                |  16 ++-
 clang/lib/CodeGen/CGBuiltin.cpp               |  53 +++----
 clang/lib/CodeGen/CGStmt.cpp                  |   5 +
 clang/lib/CodeGen/CodeGenFunction.h           |  13 ++
 clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp   |  10 ++
 clang/lib/CodeGen/Targets/AMDGPU.cpp          |   3 +
 clang/lib/Sema/SemaStmtAttr.cpp               |  60 ++++++++
 .../CodeGen/AMDGPU/amdgcn-av-non-atomic.cpp   |  43 ++++++
 .../AMDGPU/amdgcn-av-none-amdgpu-atomic.cpp   |  23 ++++
 .../AMDGPU/amdgcn-av-none-attr-c-atomic.c     |  72 ++++++++++
 .../CodeGen/AMDGPU/amdgcn-av-none-attr.cpp    | 130 ++++++++++++++++++
 15 files changed, 442 insertions(+), 27 deletions(-)
 create mode 100644 clang/test/CodeGen/AMDGPU/amdgcn-av-non-atomic.cpp
 create mode 100644 clang/test/CodeGen/AMDGPU/amdgcn-av-none-amdgpu-atomic.cpp
 create mode 100644 clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr-c-atomic.c
 create mode 100644 clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr.cpp

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 39c672322d515..4afd5bda853e7 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2532,6 +2532,12 @@ def AMDGPUMaxNumWorkGroups : InheritableAttr {
   let Subjects = SubjectList<[Function], ErrorDiag, "kernel functions">;
 }
 
+def AMDGPUAvailableVisible : StmtAttr, TargetSpecificAttr<TargetAMDGPU> {
+  let Spellings = [Clang<"amdgpu_av">];
+  let Args = [StringArgument<"Mode">];
+  let Documentation = [AMDGPUAvailableVisibleDocs];
+}
+
 def BPFPreserveAccessIndex : InheritableAttr,
                              TargetSpecificAttr<TargetBPF>  {
   let Spellings = [Clang<"preserve_access_index">];
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 05e4cb0870652..19c8ee53b951c 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3604,6 +3604,32 @@ An error will be given if:
   }];
 }
 
+def AMDGPUAvailableVisibleDocs : Documentation {
+  let Category = DocCatAMDGPUAttributes;
+  let Content = [{
+
+This attribute controls availability and visibility as described in the `AMDGPU
+Memory Model <https://llvm.org/docs/AMDGPUMemoryModel.html>`__. When placed on
+an atomic expression or fence, the resulting atomic or fence instruction carries
+the corresponding *AV Metadata*.
+
+The attribute takes a string literal as an argument, which currently has only
+one supported value:
+
+- ``"none"``: Disable MakeAvailable and MakeVisible semantics on release and
+  acquire operations respectively.
+
+.. code-block:: c++
+
+  [[clang::amdgpu_av("none")]] __atomic_thread_fence(__ATOMIC_SEQ_CST);
+  [[clang::amdgpu_av("none")]] __atomic_fetch_add(ptr, 1, __ATOMIC_ACQ_REL);
+
+  // Also works with _Atomic type qualifier operations.
+  _Atomic int *p;
+  [[clang::amdgpu_av("none")]] *p += 1;
+  }];
+}
+
 def DocCatCallingConvs : DocumentationCategory<"Calling Conventions"> {
   let Content = [{
 Clang supports several different calling conventions, depending on the target
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index b7072634cccf3..698f15c57aa9e 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -2007,3 +2007,5 @@ def ExperimentalOption : DiagGroup<"experimental-option">;
 
 // Warnings about unguarded usages of AMDGPU target specific constructs
 def UnguardedBuiltinUsageAMDGPU : DiagGroup<"amdgpu-unguarded-builtin-usage">;
+
+def AvailableVisibleAMDGPU : DiagGroup<"amdgpu-av">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index d9d0d485f16ac..3e98d264a0a09 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -14324,6 +14324,13 @@ def note_amdgcn_unguarded_builtin_silence
 
 def err_amdgcn_global_or_flat_pointer_required : Error<"builtin requires a global or generic pointer">;
 
+def warn_amdgpu_av_requires_expr : Warning<
+  "%0 attribute can only be applied to an expression">,
+  InGroup<AvailableVisibleAMDGPU>;
+def warn_amdgpu_av_requires_atomic : Warning<
+  "%0 attribute only applies to atomic expressions or Clang atomic builtins">,
+  InGroup<AvailableVisibleAMDGPU>;
+
 def err_amdgcn_dmask_has_too_many_bits_set
     : Error<"dmask argument cannot have more bits set than there are elements "
             "in return type">;
diff --git a/clang/lib/CodeGen/CGAtomic.cpp b/clang/lib/CodeGen/CGAtomic.cpp
index 61e13d4925020..cd7b278eab15d 100644
--- a/clang/lib/CodeGen/CGAtomic.cpp
+++ b/clang/lib/CodeGen/CGAtomic.cpp
@@ -631,6 +631,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr);
     Load->setAtomic(Order, Scope);
     Load->setVolatile(E->isVolatile());
+    CGF.getTargetHooks().setTargetAtomicMetadata(CGF, *Load, E);
     CGF.maybeAttachRangeForLoad(Load, E->getValueType(), E->getExprLoc());
     auto *I = CGF.Builder.CreateStore(Load, Dest);
     CGF.addInstToCurrentSourceAtom(I, Load);
@@ -648,6 +649,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr);
     Store->setAtomic(Order, Scope);
     Store->setVolatile(E->isVolatile());
+    CGF.getTargetHooks().setTargetAtomicMetadata(CGF, *Store, E);
     CGF.addInstToCurrentSourceAtom(Store, LoadVal1);
     return;
   }
@@ -822,6 +824,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
         CGF.Builder.CreateStore(CGF.Builder.getInt8(0), Ptr);
     Store->setAtomic(Order, Scope);
     Store->setVolatile(E->isVolatile());
+    CGF.getTargetHooks().setTargetAtomicMetadata(CGF, *Store, E);
     CGF.addInstToCurrentSourceAtom(Store, nullptr);
     return;
   }
@@ -1629,6 +1632,7 @@ llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO,
     Addr = castToAtomicIntPointer(Addr);
   llvm::LoadInst *Load = CGF.Builder.CreateLoad(Addr, "atomic-load");
   Load->setAtomic(AO);
+  CGF.getTargetHooks().setTargetAtomicMetadata(CGF, *Load);
 
   // Other decoration.
   if (IsVolatile)
@@ -1796,6 +1800,7 @@ std::pair<llvm::Value *, llvm::Value *> AtomicInfo::EmitAtomicCompareExchangeOp(
   // Other decoration.
   Inst->setVolatile(LVal.isVolatileQualified());
   Inst->setWeak(IsWeak);
+  CGF.getTargetHooks().setTargetAtomicMetadata(CGF, *Inst);
 
   // Okay, turn that back into the original value type.
   auto *PreviousVal = CGF.Builder.CreateExtractValue(Inst, /*Idxs=*/0);
@@ -2151,8 +2156,10 @@ void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest,
     else if (AO == llvm::AtomicOrdering::AcquireRelease)
       AO = llvm::AtomicOrdering::Release;
     // Initializations don't need to be atomic.
-    if (!isInit)
+    if (!isInit) {
       store->setAtomic(AO);
+      getTargetHooks().setTargetAtomicMetadata(*this, *store);
+    }
 
     // Other decoration.
     if (IsVolatile)
@@ -2196,6 +2203,13 @@ CodeGenFunction::emitAtomicRMWInst(llvm::AtomicRMWInst::BinOp Op, Address Addr,
   return RMW;
 }
 
+llvm::FenceInst *CodeGenFunction::emitAtomicFence(llvm::AtomicOrdering Order,
+                                                  llvm::SyncScope::ID SSID) {
+  llvm::FenceInst *Fence = Builder.CreateFence(Order, SSID);
+  getTargetHooks().setTargetAtomicMetadata(*this, *Fence);
+  return Fence;
+}
+
 void CodeGenFunction::EmitAtomicUpdate(
     LValue LVal, llvm::AtomicOrdering AO,
     const llvm::function_ref<RValue(RValue)> &UpdateOp, bool IsVolatile) {
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index f38a891272474..2dd038da20864 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -5692,16 +5692,16 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
         break;
       case 1:  // memory_order_consume
       case 2:  // memory_order_acquire
-        Builder.CreateFence(llvm::AtomicOrdering::Acquire, SSID);
+        emitAtomicFence(llvm::AtomicOrdering::Acquire, SSID);
         break;
       case 3:  // memory_order_release
-        Builder.CreateFence(llvm::AtomicOrdering::Release, SSID);
+        emitAtomicFence(llvm::AtomicOrdering::Release, SSID);
         break;
       case 4:  // memory_order_acq_rel
-        Builder.CreateFence(llvm::AtomicOrdering::AcquireRelease, SSID);
+        emitAtomicFence(llvm::AtomicOrdering::AcquireRelease, SSID);
         break;
       case 5:  // memory_order_seq_cst
-        Builder.CreateFence(llvm::AtomicOrdering::SequentiallyConsistent, SSID);
+        emitAtomicFence(llvm::AtomicOrdering::SequentiallyConsistent, SSID);
         break;
       }
       return RValue::get(nullptr);
@@ -5718,23 +5718,23 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     llvm::SwitchInst *SI = Builder.CreateSwitch(Order, ContBB);
 
     Builder.SetInsertPoint(AcquireBB);
-    Builder.CreateFence(llvm::AtomicOrdering::Acquire, SSID);
+    emitAtomicFence(llvm::AtomicOrdering::Acquire, SSID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32(1), AcquireBB);
     SI->addCase(Builder.getInt32(2), AcquireBB);
 
     Builder.SetInsertPoint(ReleaseBB);
-    Builder.CreateFence(llvm::AtomicOrdering::Release, SSID);
+    emitAtomicFence(llvm::AtomicOrdering::Release, SSID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32(3), ReleaseBB);
 
     Builder.SetInsertPoint(AcqRelBB);
-    Builder.CreateFence(llvm::AtomicOrdering::AcquireRelease, SSID);
+    emitAtomicFence(llvm::AtomicOrdering::AcquireRelease, SSID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32(4), AcqRelBB);
 
     Builder.SetInsertPoint(SeqCstBB);
-    Builder.CreateFence(llvm::AtomicOrdering::SequentiallyConsistent, SSID);
+    emitAtomicFence(llvm::AtomicOrdering::SequentiallyConsistent, SSID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32(5), SeqCstBB);
 
@@ -5758,32 +5758,32 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
         break;
       case 1: // memory_order_consume
       case 2: // memory_order_acquire
-        Builder.CreateFence(
+        emitAtomicFence(
             llvm::AtomicOrdering::Acquire,
             getTargetHooks().getLLVMSyncScopeID(getLangOpts(), SS,
                                                 llvm::AtomicOrdering::Acquire,
                                                 getLLVMContext()));
         break;
       case 3: // memory_order_release
-        Builder.CreateFence(
+        emitAtomicFence(
             llvm::AtomicOrdering::Release,
             getTargetHooks().getLLVMSyncScopeID(getLangOpts(), SS,
                                                 llvm::AtomicOrdering::Release,
                                                 getLLVMContext()));
         break;
       case 4: // memory_order_acq_rel
-        Builder.CreateFence(llvm::AtomicOrdering::AcquireRelease,
-                            getTargetHooks().getLLVMSyncScopeID(
-                                getLangOpts(), SS,
-                                llvm::AtomicOrdering::AcquireRelease,
-                                getLLVMContext()));
+        emitAtomicFence(llvm::AtomicOrdering::AcquireRelease,
+                        getTargetHooks().getLLVMSyncScopeID(
+                            getLangOpts(), SS,
+                            llvm::AtomicOrdering::AcquireRelease,
+                            getLLVMContext()));
         break;
       case 5: // memory_order_seq_cst
-        Builder.CreateFence(llvm::AtomicOrdering::SequentiallyConsistent,
-                            getTargetHooks().getLLVMSyncScopeID(
-                                getLangOpts(), SS,
-                                llvm::AtomicOrdering::SequentiallyConsistent,
-                                getLLVMContext()));
+        emitAtomicFence(
+            llvm::AtomicOrdering::SequentiallyConsistent,
+            getTargetHooks().getLLVMSyncScopeID(
+                getLangOpts(), SS, llvm::AtomicOrdering::SequentiallyConsistent,
+                getLLVMContext()));
         break;
       }
       return RValue::get(nullptr);
@@ -5844,9 +5844,9 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
         SyncScope SS = ScopeModel->isValid(Scp->getZExtValue())
                            ? ScopeModel->map(Scp->getZExtValue())
                            : ScopeModel->map(ScopeModel->getFallBackValue());
-        Builder.CreateFence(Ordering,
-                            getTargetHooks().getLLVMSyncScopeID(
-                                getLangOpts(), SS, Ordering, getLLVMContext()));
+        emitAtomicFence(Ordering,
+                        getTargetHooks().getLLVMSyncScopeID(
+                            getLangOpts(), SS, Ordering, getLLVMContext()));
         Builder.CreateBr(ContBB);
       } else {
         llvm::DenseMap<unsigned, llvm::BasicBlock *> BBs;
@@ -5860,9 +5860,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
           SI->addCase(Builder.getInt32(Scp), B);
 
           Builder.SetInsertPoint(B);
-          Builder.CreateFence(Ordering, getTargetHooks().getLLVMSyncScopeID(
-                                            getLangOpts(), ScopeModel->map(Scp),
-                                            Ordering, getLLVMContext()));
+          emitAtomicFence(Ordering,
+                          getTargetHooks().getLLVMSyncScopeID(
+                              getLangOpts(), ScopeModel->map(Scp), Ordering,
+                              getLLVMContext()));
           Builder.CreateBr(ContBB);
         }
       }
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 27e74d966eca1..aeaf2e763fcf4 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -783,6 +783,7 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
   bool noinline = false;
   bool alwaysinline = false;
   bool noconvergent = false;
+  StringRef amdgpuAVMode;
   HLSLControlFlowHintAttr::Spelling flattenOrBranch =
       HLSLControlFlowHintAttr::SpellingNotCalculated;
   const CallExpr *musttail = nullptr;
@@ -820,6 +821,9 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
     case attr::Atomic:
       AA = cast<AtomicAttr>(A);
       break;
+    case attr::AMDGPUAvailableVisible:
+      amdgpuAVMode = cast<AMDGPUAvailableVisibleAttr>(A)->getMode();
+      break;
     case attr::HLSLControlFlowHint: {
       flattenOrBranch = cast<HLSLControlFlowHintAttr>(A)->getSemanticSpelling();
     } break;
@@ -829,6 +833,7 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
   SaveAndRestore save_noinline(InNoInlineAttributedStmt, noinline);
   SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
   SaveAndRestore save_noconvergent(InNoConvergentAttributedStmt, noconvergent);
+  SaveAndRestore save_amdgpuav(AMDGPUAvailableVisibleMode, amdgpuAVMode);
   SaveAndRestore save_musttail(MustTailCall, musttail);
   SaveAndRestore save_flattenOrBranch(HLSLControlFlowAttr, flattenOrBranch);
   CGAtomicOptionsRAII AORAII(CGM, AA);
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 3fc9052adb87b..783f97dc354eb 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -624,6 +624,10 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// True if the current statement has noconvergent attribute.
   bool InNoConvergentAttributedStmt = false;
 
+  /// The mode string from the amdgpu_av attribute on the current statement,
+  /// or empty if the attribute is not present.
+  StringRef AMDGPUAvailableVisibleMode;
+
   /// HLSL Branch attribute.
   HLSLControlFlowHintAttr::Spelling HLSLControlFlowAttr =
       HLSLControlFlowHintAttr::SpellingNotCalculated;
@@ -4364,6 +4368,12 @@ class CodeGenFunction : public CodeGenTypeCache {
       llvm::SyncScope::ID SSID = llvm::SyncScope::System,
       const AtomicExpr *AE = nullptr);
 
+  /// Emit a fence instruction, applying relevant target-specific metadata when
+  /// applicable.
+  llvm::FenceInst *
+  emitAtomicFence(llvm::AtomicOrdering Order,
+                  llvm::SyncScope::ID SSID = llvm::SyncScope::System);
+
   void EmitAtomicUpdate(LValue LVal, llvm::AtomicOrdering AO,
                         const llvm::function_ref<RValue(RValue)> &UpdateOp,
                         bool IsVolatile);
@@ -4984,6 +4994,9 @@ class CodeGenFunction : public CodeGenTypeCache {
 
   void AddAMDGPUFenceAddressSpaceMMRA(llvm::Instruction *Inst,
                                       const CallExpr *E);
+  /// Attach the AMDGPU availability/visibility MMRA to \p Inst when the
+  /// amdgpu_av attribute is active on the current statement.
+  void AddAMDGPUAvailableVisibleMMRA(llvm::Instruction *Inst);
   void ProcessOrderScopeAMDGCN(llvm::Value *Order, llvm::Value *Scope,
                                llvm::AtomicOrdering &AO,
                                llvm::SyncScope::ID &SSID);
diff --git a/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp b/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
index 72d6f536165c5..cc50ce95e55e6 100644
--- a/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
+++ b/clang/lib/CodeGen/TargetBuiltins/AMDGPU.cpp
@@ -473,6 +473,14 @@ void CodeGenFunction::AddAMDGPUFenceAddressSpaceMMRA(llvm::Instruction *Inst,
   MMRAMetadata::appendTags(*Inst, MMRAs);
 }
 
+void CodeGenFunction::AddAMDGPUAvailableVisibleMMRA(llvm::Instruction *Inst) {
+  if (AMDGPUAvailableVisibleMode.empty())
+    return;
+
+  constexpr const char *Tag = "amdgcn-av";
+  MMRAMetadata::appendTags(*Inst, {{Tag, AMDGPUAvailableVisibleMode}});
+}
+
 static Value *GetAMDGPUPredicate(CodeGenFunction &CGF, Twine Name) {
   Constant *SpecId = ConstantInt::getAllOnesValue(CGF.Int32Ty);
 
@@ -1905,6 +1913,7 @@ Value *CodeGenFunction::EmitAMDGPUBuiltinExpr(unsigned BuiltinID,
     FenceInst *Fence = Builder.CreateFence(AO, SSID);
     if (E->getNumArgs() > 2)
       AddAMDGPUFenceAddressSpaceMMRA(Fence, E);
+    getTargetHooks().setTargetAtomicMetadata(*this, *Fence);
     return Fence;
   }
   case AMDGPU::BI__builtin_amdgcn_atomic_inc32:
@@ -2017,6 +2026,7 @@ Value *CodeGenFunction::EmitAMDGPUBuiltinExpr(unsigned BuiltinID,
         Builder.CreateAtomicRMW(BinOp, Ptr, Val, AO, SSID);
     if (Volatile)
       RMW->setVolatile(true);
+    AddAMDGPUAvailableVisibleMMRA(RMW);
 
     unsigned AddrSpace = Ptr.getType()->getAddressSpace();
     if (AddrSpace != llvm::AMDGPUAS::LOCAL_ADDRESS) {
diff --git a/clang/lib/CodeGen/Targets/AMDGPU.cpp b/clang/lib/CodeGen/Targets/AMDGPU.cpp
index 7b37f3f7f9b6e..b51996c6d88bf 100644
--- a/clang/lib/CodeGen/Targets/AMDGPU.cpp
+++ b/clang/lib/CodeGen/Targets/AMDGPU.cpp
@@ -10,6 +10,7 @@
 #include "TargetInfo.h"
 #include "clang/AST/DeclCXX.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/IR/MemoryModelRelaxationAnnotations.h"
 #include "llvm/Support/AMDGPUAddrSpace.h"
 
 using namespace clang;
@@ -560,6 +561,8 @@ void AMDGPUTargetCodeGenInfo::setTargetAtomicMetadata(
     AtomicInst.setMetadata(llvm::LLVMContext::MD_noalias_addrspace, ASRange);
   }
 
+  CGF.AddAMDGPUAvailableVisibleMMRA(&AtomicInst);
+
   if (!RMW)
     return;
 
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 3e9dc9c5e7e08..bad5a3e0fb919 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -363,6 +363,64 @@ static Attr *handleMustTailAttr(Sema &S, Stmt *St, const ParsedAttr &A,
   return ::new (S.Context) MustTailAttr(S.Context, A);
 }
 
+/// Return true if E is an atomic expression or a fence.
+static bool isAtomicExprOrFence(const Expr *E) {
+  E = E->IgnoreParenCasts();
+
+  if (isa<AtomicExpr>(E))
+    return true;
+
+  // _Atomic type qualifier operations: assignments and compound assignments
+  // to atomic lvalues, and loads from atomic lvalues.
+  if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
+    if (BO->getLHS()->getType()->isAtomicType())
+      return true;
+  } else if (E->getType()->isAtomicType()) {
+    return true;
+  }
+
+  // Target-independent fence builtins.
+  if (const auto *CE = dyn_cast<CallExpr>(E)) {
+    switch (CE->getBuiltinCallee()) {
+    case Builtin::BI__c11_atomic_thread_fence:
+    case Builtin::BI__c11_atomic_signal_fence:
+    case Builtin::BI__atomic_thread_fence:
+    case Builtin::BI__atomic_signal_fence:
+    case Builtin::BI__scoped_atomic_thread_fence:
+      return true;
+    default:
+      break;
+    }
+  }
+
+  return false;
+}
+
+static Attr *handleAMDGPUAvailableVisibleAttr(Sema &S, Stmt *St,
+                                              const ParsedAttr &A,
+                                              SourceRange Range) {
+  StringRef Mode;
+  if (!S.checkStringLiteralArgumentAttr(A, 0, Mode))
+    return nullptr;
+
+  if (Mode != "none") {
+    S.Diag(A.getLoc(), diag::warn_attribute_type_not_supported) << A << Mode;
+    return nullptr;
+  }
+
+  if (const auto *E = dyn_cast<Expr>(St)) {
+    if (!isAtomicExprOrFence(E)) {
+      S.Diag(A.getLoc(), diag::warn_amdgpu_av_requires_atomic) << A;
+      return nullptr;
+    }
+  } else {
+    S.Diag(A.getLoc(), diag::warn_amdgpu_av_requires_expr) << A;
+    return nullptr;
+  }
+
+  return ::new (S.Context) AMDGPUAvailableVisibleAttr(S.Context, A, Mode);
+}
+
 static Attr *handleLikely(Sema &S, Stmt *St, const ParsedAttr &A,
                           SourceRange Range) {
 
@@ -742,6 +800,8 @@ static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
     return handleNoInlineAttr(S, St, A, Range);
   case ParsedAttr::AT_MustTail:
     return handleMustTailAttr(S, St, A, Range);
+  case ParsedAttr::AT_AMDGPUAvailableVisible:
+    return handleAMDGPUAvailableVisibleAttr(S, St, A, Range);
   case ParsedAttr::AT_Likely:
     return handleLikely(S, St, A, Range);
   case ParsedAttr::AT_Unlikely:
diff --git a/clang/test/CodeGen/AMDGPU/amdgcn-av-non-atomic.cpp b/clang/test/CodeGen/AMDGPU/amdgcn-av-non-atomic.cpp
new file mode 100644
index 0000000000000..46fbdec7b7a41
--- /dev/null
+++ b/clang/test/CodeGen/AMDGPU/amdgcn-av-non-atomic.cpp
@@ -0,0 +1,43 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 %s -emit-llvm -O0 -verify -o - \
+// RUN:   -triple=amdgcn-amd-amdhsa | FileCheck %s
+
+// Test that [[clang::amdgpu_av("none")]] on non-atomic statements emits a
+// warning and does NOT produce !mmra metadata.
+
+// CHECK-LABEL: define {{.*}} @_Z16test_plain_storePii(
+// CHECK-NOT: !mmra
+// CHECK: ret void
+void test_plain_store(int *p, int val) {
+  [[clang::amdgpu_av("none")]] *p = val; // expected-warning {{'clang::amdgpu_av' attribute only applies to atomic expressions or Clang atomic builtins}}
+}
+
+// CHECK-LABEL: define {{.*}} @_Z15test_plain_callv(
+// CHECK-NOT: !mmra
+// CHECK: ret void
+extern void foo();
+void test_plain_call() {
+  [[clang::amdgpu_av("none")]] foo(); // expected-warning {{'clang::amdgpu_av' attribute only applies to atomic expressions or Clang atomic builtins}}
+}
+
+// CHECK-LABEL: define {{.*}} @_Z18test_for_with_atomPi(
+// CHECK-NOT: !mmra
+// CHECK: ret void
+void test_for_with_atom(int *p) {
+  // The attribute on a for loop should warn even if the body contains atomics.
+  [[clang::amdgpu_av("none")]] for (;;) { // expected-warning {{'clang::amdgpu_av' attribute can only be applied to an expression}}
+    __atomic_fetch_add(p, 1, __ATOMIC_SEQ_CST);
+    break;
+  }
+}
+
+// The attribute on an if statement should warn even if the condition is atomic.
+// CHECK-LABEL: define {{.*}} @_Z20test_if_atomic_condnPi(
+// CHECK-NOT: !mmra
+// CHECK: ret void
+void test_if_atomic_condn(int *p) {
+  [[clang::amdgpu_av("none")]] if (__atomic_load_n(p, __ATOMIC_ACQUIRE)) { // expected-warning {{'clang::amdgpu_av' attribute can only be applied to an expression}}
+  }
+}
+
+// CHECK-NOT: amdgcn-av
diff --git a/clang/test/CodeGen/AMDGPU/amdgcn-av-none-amdgpu-atomic.cpp b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-amdgpu-atomic.cpp
new file mode 100644
index 0000000000000..ada72942dcd4c
--- /dev/null
+++ b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-amdgpu-atomic.cpp
@@ -0,0 +1,23 @@
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 %s -verify -emit-llvm -O0 -o - \
+// RUN:   -triple=amdgcn-amd-amdhsa \
+// RUN:   -target-cpu gfx942
+
+// Test that [[clang::amdgpu_av("none")]] on AMDGPU-specific atomic builtins
+// is rejected with a warning.
+
+void test_atomic_inc32_av(volatile unsigned *p, unsigned val) {
+  [[clang::amdgpu_av("none")]] __builtin_amdgcn_atomic_inc32(p, val, __ATOMIC_SEQ_CST, "agent"); // expected-warning {{only applies to atomic expressions or Clang atomic builtins}}
+}
+
+void test_atomic_dec64_av(volatile unsigned long long *p, unsigned long long val) {
+  [[clang::amdgpu_av("none")]] __builtin_amdgcn_atomic_dec64(p, val, __ATOMIC_ACQUIRE, "agent"); // expected-warning {{only applies to atomic expressions or Clang atomic builtins}}
+}
+
+void test_ds_faddf_av(float __attribute__((address_space(3))) *p, float val) {
+  [[clang::amdgpu_av("none")]] __builtin_amdgcn_ds_faddf(p, val, __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE, false); // expected-warning {{only applies to atomic expressions or Clang atomic builtins}}
+}
+
+void test_global_atomic_fadd_av(float __attribute__((address_space(1))) *p, float val) {
+  [[clang::amdgpu_av("none")]] __builtin_amdgcn_global_atomic_fadd_f32(p, val); // expected-warning {{only applies to atomic expressions or Clang atomic builtins}}
+}
diff --git a/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr-c-atomic.c b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr-c-atomic.c
new file mode 100644
index 0000000000000..9ae0e88a27a6a
--- /dev/null
+++ b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr-c-atomic.c
@@ -0,0 +1,72 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 6
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 %s -emit-llvm -O0 -o - \
+// RUN:   -triple=amdgcn-amd-amdhsa -std=c23 | FileCheck %s
+
+// Test that [[clang::amdgpu_av("none")]] works with _Atomic type
+// qualifier operations, which go through CGExprScalar and CGAtomic
+// codegen paths.
+
+// CHECK-LABEL: define dso_local void @test_atomic_rmw_add(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = atomicrmw add ptr [[TMP0]], i32 1 seq_cst, align 4, !mmra [[META2:![0-9]+]], !amdgpu.no.fine.grained.memory [[META3:![0-9]+]], !amdgpu.no.remote.memory [[META3]]
+// CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], 1
+// CHECK-NEXT:    ret void
+//
+void test_atomic_rmw_add(_Atomic int *p) {
+  [[clang::amdgpu_av("none")]] *p += 1;
+}
+
+// CHECK-LABEL: define dso_local void @test_atomic_store(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store atomic i32 42, ptr [[TMP0]] seq_cst, align 4, !mmra [[META2]]
+// CHECK-NEXT:    ret void
+//
+void test_atomic_store(_Atomic int *p) {
+  [[clang::amdgpu_av("none")]] *p = 42;
+}
+
+// CHECK-LABEL: define dso_local void @test_atomic_load(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[ATOMIC_LOAD:%.*]] = load atomic i32, ptr [[TMP0]] seq_cst, align 4, !mmra [[META2]]
+// CHECK-NEXT:    ret void
+//
+void test_atomic_load(_Atomic int *p) {
+  [[clang::amdgpu_av("none")]] (void)*p;
+}
+
+// --- Negative control: no attribute ---
+
+// CHECK-LABEL: define dso_local void @test_no_attr(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = atomicrmw add ptr [[TMP0]], i32 1 seq_cst, align 4, !amdgpu.no.fine.grained.memory [[META3]], !amdgpu.no.remote.memory [[META3]]
+// CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], 1
+// CHECK-NEXT:    ret void
+//
+void test_no_attr(_Atomic int *p) {
+  *p += 1;
+}
+//.
+// CHECK: [[META2]] = !{!"amdgcn-av", !"none"}
+// CHECK: [[META3]] = !{}
+//.
diff --git a/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr.cpp b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr.cpp
new file mode 100644
index 0000000000000..38071f466c3a8
--- /dev/null
+++ b/clang/test/CodeGen/AMDGPU/amdgcn-av-none-attr.cpp
@@ -0,0 +1,130 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 4
+// REQUIRES: amdgpu-registered-target
+// RUN: %clang_cc1 %s -emit-llvm -O0 -o - \
+// RUN:   -triple=amdgcn-amd-amdhsa | FileCheck %s
+
+// Test that [[clang::amdgpu_av("none")]] on atomic builtins emits
+// !mmra !{!"amdgcn-av", !"none"} metadata on the resulting IR instructions.
+
+// CHECK-LABEL: define dso_local void @_Z21test_atomic_fetch_addPi(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[DOTATOMICTMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store i32 1, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP2:%.*]] = atomicrmw add ptr [[TMP0]], i32 [[TMP1]] seq_cst, align 4, !mmra [[META2:![0-9]+]], !amdgpu.no.fine.grained.memory [[META3:![0-9]+]], !amdgpu.no.remote.memory [[META3]]
+// CHECK-NEXT:    store i32 [[TMP2]], ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    [[TMP3:%.*]] = load i32, ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    ret void
+//
+void test_atomic_fetch_add(int *p) {
+  [[clang::amdgpu_av("none")]] __atomic_fetch_add(p, 1, __ATOMIC_SEQ_CST);
+}
+
+// CHECK-LABEL: define dso_local void @_Z17test_atomic_storePi(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[DOTATOMICTMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store i32 42, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    store atomic i32 [[TMP1]], ptr [[TMP0]] release, align 4, !mmra [[META2]]
+// CHECK-NEXT:    ret void
+//
+void test_atomic_store(int *p) {
+  [[clang::amdgpu_av("none")]] __atomic_store_n(p, 42, __ATOMIC_RELEASE);
+}
+
+// CHECK-LABEL: define dso_local void @_Z16test_atomic_loadPi(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = load atomic i32, ptr [[TMP0]] acquire, align 4, !mmra [[META2]]
+// CHECK-NEXT:    store i32 [[TMP1]], ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    [[TMP2:%.*]] = load i32, ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    ret void
+//
+void test_atomic_load(int *p) {
+  [[clang::amdgpu_av("none")]] __atomic_load_n(p, __ATOMIC_ACQUIRE);
+}
+
+// CHECK-LABEL: define dso_local void @_Z19test_atomic_cmpxchgPi(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[EXPECTED:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[DOTATOMICTMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[CMPXCHG_BOOL:%.*]] = alloca i8, align 1, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    [[EXPECTED_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[EXPECTED]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store i32 0, ptr [[EXPECTED_ASCAST]], align 4
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store i32 1, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr [[EXPECTED_ASCAST]], align 4
+// CHECK-NEXT:    [[TMP2:%.*]] = load i32, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP3:%.*]] = cmpxchg ptr [[TMP0]], i32 [[TMP1]], i32 [[TMP2]] seq_cst acquire, align 4, !mmra [[META2]]
+// CHECK-NEXT:    [[TMP4:%.*]] = extractvalue { i32, i1 } [[TMP3]], 0
+// CHECK-NEXT:    [[TMP5:%.*]] = extractvalue { i32, i1 } [[TMP3]], 1
+// CHECK-NEXT:    br i1 [[TMP5]], label [[CMPXCHG_CONTINUE:%.*]], label [[CMPXCHG_STORE_EXPECTED:%.*]]
+// CHECK:       cmpxchg.store_expected:
+// CHECK-NEXT:    store i32 [[TMP4]], ptr [[EXPECTED_ASCAST]], align 4
+// CHECK-NEXT:    br label [[CMPXCHG_CONTINUE]]
+// CHECK:       cmpxchg.continue:
+// CHECK-NEXT:    [[STOREDV:%.*]] = zext i1 [[TMP5]] to i8
+// CHECK-NEXT:    store i8 [[STOREDV]], ptr addrspace(5) [[CMPXCHG_BOOL]], align 1
+// CHECK-NEXT:    [[TMP6:%.*]] = load i8, ptr addrspace(5) [[CMPXCHG_BOOL]], align 1
+// CHECK-NEXT:    [[LOADEDV:%.*]] = icmp ne i8 [[TMP6]], 0
+// CHECK-NEXT:    ret void
+//
+void test_atomic_cmpxchg(int *p) {
+  int expected = 0;
+  [[clang::amdgpu_av("none")]] __atomic_compare_exchange_n(p, &expected, 1, false, __ATOMIC_SEQ_CST, __ATOMIC_ACQUIRE);
+}
+
+// CHECK-LABEL: define dso_local void @_Z24test_atomic_thread_fencev(
+// CHECK-SAME: ) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    fence seq_cst, !mmra [[META2]]
+// CHECK-NEXT:    ret void
+//
+void test_atomic_thread_fence() {
+  [[clang::amdgpu_av("none")]] __atomic_thread_fence(__ATOMIC_SEQ_CST);
+}
+
+// Verify that without the attribute, no !mmra metadata is emitted.
+// CHECK-LABEL: define dso_local void @_Z12test_no_attrPi(
+// CHECK-SAME: ptr noundef [[P:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[P_ADDR:%.*]] = alloca ptr, align 8, addrspace(5)
+// CHECK-NEXT:    [[DOTATOMICTMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[ATOMIC_TEMP:%.*]] = alloca i32, align 4, addrspace(5)
+// CHECK-NEXT:    [[P_ADDR_ASCAST:%.*]] = addrspacecast ptr addrspace(5) [[P_ADDR]] to ptr
+// CHECK-NEXT:    store ptr [[P]], ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[P_ADDR_ASCAST]], align 8
+// CHECK-NEXT:    store i32 1, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr addrspace(5) [[DOTATOMICTMP]], align 4
+// CHECK-NEXT:    [[TMP2:%.*]] = atomicrmw add ptr [[TMP0]], i32 [[TMP1]] seq_cst, align 4, !amdgpu.no.fine.grained.memory [[META3]], !amdgpu.no.remote.memory [[META3]]
+// CHECK-NEXT:    store i32 [[TMP2]], ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    [[TMP3:%.*]] = load i32, ptr addrspace(5) [[ATOMIC_TEMP]], align 4
+// CHECK-NEXT:    ret void
+//
+void test_no_attr(int *p) {
+  __atomic_fetch_add(p, 1, __ATOMIC_SEQ_CST);
+}
+//.
+// CHECK: [[META2]] = !{!"amdgcn-av", !"none"}
+// CHECK: [[META3]] = !{}
+//.



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