Add OpenCL 2.0 atomic builtin functions as Clang builtin

OpenCL 2.0 atomic builtin functions have a scope argument which is ideally
represented as synchronization scope argument in LLVM atomic instructions.

Clang supports translating Clang atomic builtin functions to LLVM atomic
instructions. However it currently does not support synchronization scope
of LLVM atomic instructions. Without this, users have to use LLVM assembly
code to implement OpenCL atomic builtin functions.

This patch adds OpenCL 2.0 atomic builtin functions as Clang builtin
functions, which supports generating LLVM atomic instructions with
synchronization scope operand.

Currently only constant memory scope argument is supported. Support of
non-constant memory scope argument will be added later.

Differential Revision: https://reviews.llvm.org/D28691


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@310082 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 183 insertions, 37 deletions

diff --git a/lib/CodeGen/CGAtomic.cpp b/lib/CodeGen/CGAtomic.cpp
index a6e6fec206..5e6633fff1 100644
--- a/lib/CodeGen/CGAtomic.cpp
+++ b/lib/CodeGen/CGAtomic.cpp
@@ -15,6 +15,7 @@
 #include "CGRecordLayout.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
+#include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "llvm/IR/DataLayout.h"
@@ -359,13 +360,15 @@ static void emitAtomicCmpXchg(CodeGenFunction &CGF, AtomicExpr *E, bool IsWeak,
                               Address Val1, Address Val2,
                               uint64_t Size,
                               llvm::AtomicOrdering SuccessOrder,
-                              llvm::AtomicOrdering FailureOrder) {
+                              llvm::AtomicOrdering FailureOrder,
+                              llvm::SyncScope::ID Scope) {
   // Note that cmpxchg doesn't support weak cmpxchg, at least at the moment.
   llvm::Value *Expected = CGF.Builder.CreateLoad(Val1);
   llvm::Value *Desired = CGF.Builder.CreateLoad(Val2);
 
   llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg(
-      Ptr.getPointer(), Expected, Desired, SuccessOrder, FailureOrder);
+      Ptr.getPointer(), Expected, Desired, SuccessOrder, FailureOrder,
+      Scope);
   Pair->setVolatile(E->isVolatile());
   Pair->setWeak(IsWeak);
 
@@ -407,7 +410,8 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
                                         Address Val1, Address Val2,
                                         llvm::Value *FailureOrderVal,
                                         uint64_t Size,
-                                        llvm::AtomicOrdering SuccessOrder) {
+                                        llvm::AtomicOrdering SuccessOrder,
+                                        llvm::SyncScope::ID Scope) {
   llvm::AtomicOrdering FailureOrder;
   if (llvm::ConstantInt *FO = dyn_cast<llvm::ConstantInt>(FailureOrderVal)) {
     auto FOS = FO->getSExtValue();
@@ -435,7 +439,7 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
           llvm::AtomicCmpXchgInst::getStrongestFailureOrdering(SuccessOrder);
     }
     emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder,
-                      FailureOrder);
+                      FailureOrder, Scope);
     return;
   }
 
@@ -460,13 +464,13 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
   // doesn't fold to a constant for the ordering.
   CGF.Builder.SetInsertPoint(MonotonicBB);
   emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
-                    Size, SuccessOrder, llvm::AtomicOrdering::Monotonic);
+                    Size, SuccessOrder, llvm::AtomicOrdering::Monotonic, Scope);
   CGF.Builder.CreateBr(ContBB);
 
   if (AcquireBB) {
     CGF.Builder.SetInsertPoint(AcquireBB);
     emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2,
-                      Size, SuccessOrder, llvm::AtomicOrdering::Acquire);
+                      Size, SuccessOrder, llvm::AtomicOrdering::Acquire, Scope);
     CGF.Builder.CreateBr(ContBB);
     SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::consume),
                 AcquireBB);
@@ -476,7 +480,7 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
   if (SeqCstBB) {
     CGF.Builder.SetInsertPoint(SeqCstBB);
     emitAtomicCmpXchg(CGF, E, IsWeak, Dest, Ptr, Val1, Val2, Size, SuccessOrder,
-                      llvm::AtomicOrdering::SequentiallyConsistent);
+                      llvm::AtomicOrdering::SequentiallyConsistent, Scope);
     CGF.Builder.CreateBr(ContBB);
     SI->addCase(CGF.Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst),
                 SeqCstBB);
@@ -488,27 +492,31 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
 static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
                          Address Ptr, Address Val1, Address Val2,
                          llvm::Value *IsWeak, llvm::Value *FailureOrder,
-                         uint64_t Size, llvm::AtomicOrdering Order) {
+                         uint64_t Size, llvm::AtomicOrdering Order,
+                         llvm::SyncScope::ID Scope) {
   llvm::AtomicRMWInst::BinOp Op = llvm::AtomicRMWInst::Add;
   llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0;
 
   switch (E->getOp()) {
   case AtomicExpr::AO__c11_atomic_init:
+  case AtomicExpr::AO__opencl_atomic_init:
     llvm_unreachable("Already handled!");
 
   case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
+  case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
     emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
-                                FailureOrder, Size, Order);
+                                FailureOrder, Size, Order, Scope);
     return;
   case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
+  case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
     emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
-                                FailureOrder, Size, Order);
+                                FailureOrder, Size, Order, Scope);
     return;
   case AtomicExpr::AO__atomic_compare_exchange:
   case AtomicExpr::AO__atomic_compare_exchange_n: {
     if (llvm::ConstantInt *IsWeakC = dyn_cast<llvm::ConstantInt>(IsWeak)) {
       emitAtomicCmpXchgFailureSet(CGF, E, IsWeakC->getZExtValue(), Dest, Ptr,
-                                  Val1, Val2, FailureOrder, Size, Order);
+                                  Val1, Val2, FailureOrder, Size, Order, Scope);
     } else {
       // Create all the relevant BB's
       llvm::BasicBlock *StrongBB =
@@ -522,12 +530,12 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
 
       CGF.Builder.SetInsertPoint(StrongBB);
       emitAtomicCmpXchgFailureSet(CGF, E, false, Dest, Ptr, Val1, Val2,
-                                  FailureOrder, Size, Order);
+                                  FailureOrder, Size, Order, Scope);
       CGF.Builder.CreateBr(ContBB);
 
       CGF.Builder.SetInsertPoint(WeakBB);
       emitAtomicCmpXchgFailureSet(CGF, E, true, Dest, Ptr, Val1, Val2,
-                                  FailureOrder, Size, Order);
+                                  FailureOrder, Size, Order, Scope);
       CGF.Builder.CreateBr(ContBB);
 
       CGF.Builder.SetInsertPoint(ContBB);
@@ -535,26 +543,29 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     return;
   }
   case AtomicExpr::AO__c11_atomic_load:
+  case AtomicExpr::AO__opencl_atomic_load:
   case AtomicExpr::AO__atomic_load_n:
   case AtomicExpr::AO__atomic_load: {
     llvm::LoadInst *Load = CGF.Builder.CreateLoad(Ptr);
-    Load->setAtomic(Order);
+    Load->setAtomic(Order, Scope);
     Load->setVolatile(E->isVolatile());
     CGF.Builder.CreateStore(Load, Dest);
     return;
   }
 
   case AtomicExpr::AO__c11_atomic_store:
+  case AtomicExpr::AO__opencl_atomic_store:
   case AtomicExpr::AO__atomic_store:
   case AtomicExpr::AO__atomic_store_n: {
     llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1);
     llvm::StoreInst *Store = CGF.Builder.CreateStore(LoadVal1, Ptr);
-    Store->setAtomic(Order);
+    Store->setAtomic(Order, Scope);
     Store->setVolatile(E->isVolatile());
     return;
   }
 
   case AtomicExpr::AO__c11_atomic_exchange:
+  case AtomicExpr::AO__opencl_atomic_exchange:
   case AtomicExpr::AO__atomic_exchange_n:
   case AtomicExpr::AO__atomic_exchange:
     Op = llvm::AtomicRMWInst::Xchg;
@@ -564,6 +575,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     PostOp = llvm::Instruction::Add;
     // Fall through.
   case AtomicExpr::AO__c11_atomic_fetch_add:
+  case AtomicExpr::AO__opencl_atomic_fetch_add:
   case AtomicExpr::AO__atomic_fetch_add:
     Op = llvm::AtomicRMWInst::Add;
     break;
@@ -572,14 +584,26 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     PostOp = llvm::Instruction::Sub;
     // Fall through.
   case AtomicExpr::AO__c11_atomic_fetch_sub:
+  case AtomicExpr::AO__opencl_atomic_fetch_sub:
   case AtomicExpr::AO__atomic_fetch_sub:
     Op = llvm::AtomicRMWInst::Sub;
     break;
 
+  case AtomicExpr::AO__opencl_atomic_fetch_min:
+    Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Min
+                                                  : llvm::AtomicRMWInst::UMin;
+    break;
+
+  case AtomicExpr::AO__opencl_atomic_fetch_max:
+    Op = E->getValueType()->isSignedIntegerType() ? llvm::AtomicRMWInst::Max
+                                                  : llvm::AtomicRMWInst::UMax;
+    break;
+
   case AtomicExpr::AO__atomic_and_fetch:
     PostOp = llvm::Instruction::And;
     // Fall through.
   case AtomicExpr::AO__c11_atomic_fetch_and:
+  case AtomicExpr::AO__opencl_atomic_fetch_and:
   case AtomicExpr::AO__atomic_fetch_and:
     Op = llvm::AtomicRMWInst::And;
     break;
@@ -588,6 +612,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     PostOp = llvm::Instruction::Or;
     // Fall through.
   case AtomicExpr::AO__c11_atomic_fetch_or:
+  case AtomicExpr::AO__opencl_atomic_fetch_or:
   case AtomicExpr::AO__atomic_fetch_or:
     Op = llvm::AtomicRMWInst::Or;
     break;
@@ -596,6 +621,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
     PostOp = llvm::Instruction::Xor;
     // Fall through.
   case AtomicExpr::AO__c11_atomic_fetch_xor:
+  case AtomicExpr::AO__opencl_atomic_fetch_xor:
   case AtomicExpr::AO__atomic_fetch_xor:
     Op = llvm::AtomicRMWInst::Xor;
     break;
@@ -610,7 +636,7 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
 
   llvm::Value *LoadVal1 = CGF.Builder.CreateLoad(Val1);
   llvm::AtomicRMWInst *RMWI =
-      CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order);
+      CGF.Builder.CreateAtomicRMW(Op, Ptr.getPointer(), LoadVal1, Order, Scope);
   RMWI->setVolatile(E->isVolatile());
 
   // For __atomic_*_fetch operations, perform the operation again to
@@ -677,19 +703,23 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
   Address Dest = Address::invalid();
   Address Ptr(EmitScalarExpr(E->getPtr()), alignChars);
 
-  if (E->getOp() == AtomicExpr::AO__c11_atomic_init) {
+  if (E->getOp() == AtomicExpr::AO__c11_atomic_init ||
+      E->getOp() == AtomicExpr::AO__opencl_atomic_init) {
     LValue lvalue = MakeAddrLValue(Ptr, AtomicTy);
     EmitAtomicInit(E->getVal1(), lvalue);
     return RValue::get(nullptr);
   }
 
   llvm::Value *Order = EmitScalarExpr(E->getOrder());
+  llvm::Value *Scope = EmitScalarExpr(E->getScope());
 
   switch (E->getOp()) {
   case AtomicExpr::AO__c11_atomic_init:
+  case AtomicExpr::AO__opencl_atomic_init:
     llvm_unreachable("Already handled above with EmitAtomicInit!");
 
   case AtomicExpr::AO__c11_atomic_load:
+  case AtomicExpr::AO__opencl_atomic_load:
   case AtomicExpr::AO__atomic_load_n:
     break;
 
@@ -708,6 +738,8 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
 
   case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
   case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
+  case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
+  case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
   case AtomicExpr::AO__atomic_compare_exchange_n:
   case AtomicExpr::AO__atomic_compare_exchange:
     Val1 = EmitPointerWithAlignment(E->getVal1());
@@ -716,12 +748,15 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     else
       Val2 = EmitValToTemp(*this, E->getVal2());
     OrderFail = EmitScalarExpr(E->getOrderFail());
-    if (E->getNumSubExprs() == 6)
+    if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n ||
+        E->getOp() == AtomicExpr::AO__atomic_compare_exchange)
       IsWeak = EmitScalarExpr(E->getWeak());
     break;
 
   case AtomicExpr::AO__c11_atomic_fetch_add:
   case AtomicExpr::AO__c11_atomic_fetch_sub:
+  case AtomicExpr::AO__opencl_atomic_fetch_add:
+  case AtomicExpr::AO__opencl_atomic_fetch_sub:
     if (MemTy->isPointerType()) {
       // For pointer arithmetic, we're required to do a bit of math:
       // adding 1 to an int* is not the same as adding 1 to a uintptr_t.
@@ -744,11 +779,18 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
   case AtomicExpr::AO__atomic_sub_fetch:
   case AtomicExpr::AO__c11_atomic_store:
   case AtomicExpr::AO__c11_atomic_exchange:
+  case AtomicExpr::AO__opencl_atomic_store:
+  case AtomicExpr::AO__opencl_atomic_exchange:
   case AtomicExpr::AO__atomic_store_n:
   case AtomicExpr::AO__atomic_exchange_n:
   case AtomicExpr::AO__c11_atomic_fetch_and:
   case AtomicExpr::AO__c11_atomic_fetch_or:
   case AtomicExpr::AO__c11_atomic_fetch_xor:
+  case AtomicExpr::AO__opencl_atomic_fetch_and:
+  case AtomicExpr::AO__opencl_atomic_fetch_or:
+  case AtomicExpr::AO__opencl_atomic_fetch_xor:
+  case AtomicExpr::AO__opencl_atomic_fetch_min:
+  case AtomicExpr::AO__opencl_atomic_fetch_max:
   case AtomicExpr::AO__atomic_fetch_and:
   case AtomicExpr::AO__atomic_fetch_or:
   case AtomicExpr::AO__atomic_fetch_xor:
@@ -784,18 +826,26 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     bool UseOptimizedLibcall = false;
     switch (E->getOp()) {
     case AtomicExpr::AO__c11_atomic_init:
+    case AtomicExpr::AO__opencl_atomic_init:
       llvm_unreachable("Already handled above with EmitAtomicInit!");
 
     case AtomicExpr::AO__c11_atomic_fetch_add:
+    case AtomicExpr::AO__opencl_atomic_fetch_add:
     case AtomicExpr::AO__atomic_fetch_add:
     case AtomicExpr::AO__c11_atomic_fetch_and:
+    case AtomicExpr::AO__opencl_atomic_fetch_and:
     case AtomicExpr::AO__atomic_fetch_and:
     case AtomicExpr::AO__c11_atomic_fetch_or:
+    case AtomicExpr::AO__opencl_atomic_fetch_or:
     case AtomicExpr::AO__atomic_fetch_or:
     case AtomicExpr::AO__atomic_fetch_nand:
     case AtomicExpr::AO__c11_atomic_fetch_sub:
+    case AtomicExpr::AO__opencl_atomic_fetch_sub:
     case AtomicExpr::AO__atomic_fetch_sub:
     case AtomicExpr::AO__c11_atomic_fetch_xor:
+    case AtomicExpr::AO__opencl_atomic_fetch_xor:
+    case AtomicExpr::AO__opencl_atomic_fetch_min:
+    case AtomicExpr::AO__opencl_atomic_fetch_max:
     case AtomicExpr::AO__atomic_fetch_xor:
     case AtomicExpr::AO__atomic_add_fetch:
     case AtomicExpr::AO__atomic_and_fetch:
@@ -812,6 +862,11 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     case AtomicExpr::AO__c11_atomic_exchange:
     case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
     case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
+    case AtomicExpr::AO__opencl_atomic_load:
+    case AtomicExpr::AO__opencl_atomic_store:
+    case AtomicExpr::AO__opencl_atomic_exchange:
+    case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
+    case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
     case AtomicExpr::AO__atomic_load_n:
     case AtomicExpr::AO__atomic_load:
     case AtomicExpr::AO__atomic_store_n:
@@ -833,7 +888,24 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
                getContext().getSizeType());
     }
     // Atomic address is the first or second parameter
-    Args.add(RValue::get(EmitCastToVoidPtr(Ptr.getPointer())),
+    // The OpenCL atomic library functions only accept pointer arguments to
+    // generic address space.
+    auto CastToGenericAddrSpace = [&](llvm::Value *V, QualType PT) {
+      if (!E->isOpenCL())
+        return V;
+      auto AS = PT->getAs<PointerType>()->getPointeeType().getAddressSpace();
+      if (AS == LangAS::opencl_generic)
+        return V;
+      auto DestAS = getContext().getTargetAddressSpace(LangAS::opencl_generic);
+      auto T = V->getType();
+      auto *DestType = T->getPointerElementType()->getPointerTo(DestAS);
+
+      return getTargetHooks().performAddrSpaceCast(
+          *this, V, AS, LangAS::opencl_generic, DestType, false);
+    };
+
+    Args.add(RValue::get(CastToGenericAddrSpace(
+                 EmitCastToVoidPtr(Ptr.getPointer()), E->getPtr()->getType())),
              getContext().VoidPtrTy);
 
     std::string LibCallName;
@@ -844,6 +916,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     llvm::Instruction::BinaryOps PostOp = (llvm::Instruction::BinaryOps)0;
     switch (E->getOp()) {
     case AtomicExpr::AO__c11_atomic_init:
+    case AtomicExpr::AO__opencl_atomic_init:
       llvm_unreachable("Already handled!");
 
     // There is only one libcall for compare an exchange, because there is no
@@ -855,13 +928,17 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     //                                  int success, int failure)
     case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
     case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
+    case AtomicExpr::AO__opencl_atomic_compare_exchange_weak:
+    case AtomicExpr::AO__opencl_atomic_compare_exchange_strong:
     case AtomicExpr::AO__atomic_compare_exchange:
     case AtomicExpr::AO__atomic_compare_exchange_n:
       LibCallName = "__atomic_compare_exchange";
       RetTy = getContext().BoolTy;
       HaveRetTy = true;
-      Args.add(RValue::get(EmitCastToVoidPtr(Val1.getPointer())),
-               getContext().VoidPtrTy);
+      Args.add(
+          RValue::get(CastToGenericAddrSpace(
+              EmitCastToVoidPtr(Val1.getPointer()), E->getVal1()->getType())),
+          getContext().VoidPtrTy);
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val2.getPointer(),
                         MemTy, E->getExprLoc(), sizeChars);
       Args.add(RValue::get(Order), getContext().IntTy);
@@ -871,6 +948,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     //                        int order)
     // T __atomic_exchange_N(T *mem, T val, int order)
     case AtomicExpr::AO__c11_atomic_exchange:
+    case AtomicExpr::AO__opencl_atomic_exchange:
     case AtomicExpr::AO__atomic_exchange_n:
     case AtomicExpr::AO__atomic_exchange:
       LibCallName = "__atomic_exchange";
@@ -880,6 +958,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     // void __atomic_store(size_t size, void *mem, void *val, int order)
     // void __atomic_store_N(T *mem, T val, int order)
     case AtomicExpr::AO__c11_atomic_store:
+    case AtomicExpr::AO__opencl_atomic_store:
     case AtomicExpr::AO__atomic_store:
     case AtomicExpr::AO__atomic_store_n:
       LibCallName = "__atomic_store";
@@ -891,6 +970,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     // void __atomic_load(size_t size, void *mem, void *return, int order)
     // T __atomic_load_N(T *mem, int order)
     case AtomicExpr::AO__c11_atomic_load:
+    case AtomicExpr::AO__opencl_atomic_load:
     case AtomicExpr::AO__atomic_load:
     case AtomicExpr::AO__atomic_load_n:
       LibCallName = "__atomic_load";
@@ -901,6 +981,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       PostOp = llvm::Instruction::Add;
     // Fall through.
     case AtomicExpr::AO__c11_atomic_fetch_add:
+    case AtomicExpr::AO__opencl_atomic_fetch_add:
     case AtomicExpr::AO__atomic_fetch_add:
       LibCallName = "__atomic_fetch_add";
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
@@ -912,6 +993,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       PostOp = llvm::Instruction::And;
     // Fall through.
     case AtomicExpr::AO__c11_atomic_fetch_and:
+    case AtomicExpr::AO__opencl_atomic_fetch_and:
     case AtomicExpr::AO__atomic_fetch_and:
       LibCallName = "__atomic_fetch_and";
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
@@ -923,6 +1005,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       PostOp = llvm::Instruction::Or;
     // Fall through.
     case AtomicExpr::AO__c11_atomic_fetch_or:
+    case AtomicExpr::AO__opencl_atomic_fetch_or:
     case AtomicExpr::AO__atomic_fetch_or:
       LibCallName = "__atomic_fetch_or";
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
@@ -934,6 +1017,7 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       PostOp = llvm::Instruction::Sub;
     // Fall through.
     case AtomicExpr::AO__c11_atomic_fetch_sub:
+    case AtomicExpr::AO__opencl_atomic_fetch_sub:
     case AtomicExpr::AO__atomic_fetch_sub:
       LibCallName = "__atomic_fetch_sub";
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
@@ -945,11 +1029,26 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       PostOp = llvm::Instruction::Xor;
     // Fall through.
     case AtomicExpr::AO__c11_atomic_fetch_xor:
+    case AtomicExpr::AO__opencl_atomic_fetch_xor:
     case AtomicExpr::AO__atomic_fetch_xor:
       LibCallName = "__atomic_fetch_xor";
       AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
                         MemTy, E->getExprLoc(), sizeChars);
       break;
+    case AtomicExpr::AO__opencl_atomic_fetch_min:
+      LibCallName = E->getValueType()->isSignedIntegerType()
+                        ? "__atomic_fetch_min"
+                        : "__atomic_fetch_umin";
+      AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
+                        LoweredMemTy, E->getExprLoc(), sizeChars);
+      break;
+    case AtomicExpr::AO__opencl_atomic_fetch_max:
+      LibCallName = E->getValueType()->isSignedIntegerType()
+                        ? "__atomic_fetch_max"
+                        : "__atomic_fetch_umax";
+      AddDirectArgument(*this, Args, UseOptimizedLibcall, Val1.getPointer(),
+                        LoweredMemTy, E->getExprLoc(), sizeChars);
+      break;
     // T __atomic_nand_fetch_N(T *mem, T val, int order)
     // T __atomic_fetch_nand_N(T *mem, T val, int order)
     case AtomicExpr::AO__atomic_nand_fetch:
@@ -962,6 +1061,11 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       break;
     }
 
+    if (E->isOpenCL()) {
+      LibCallName = std::string("__opencl") +
+          StringRef(LibCallName).drop_front(1).str();
+
+    }
     // Optimized functions have the size in their name.
     if (UseOptimizedLibcall)
       LibCallName += "_" + llvm::utostr(Size);
@@ -982,6 +1086,8 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
     // order is always the last parameter
     Args.add(RValue::get(Order),
              getContext().IntTy);
+    if (E->isOpenCL())
+      Args.add(RValue::get(Scope), getContext().IntTy);
 
     // PostOp is only needed for the atomic_*_fetch operations, and
     // thus is only needed for and implemented in the
@@ -1018,12 +1124,20 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
   }
 
   bool IsStore = E->getOp() == AtomicExpr::AO__c11_atomic_store ||
+                 E->getOp() == AtomicExpr::AO__opencl_atomic_store ||
                  E->getOp() == AtomicExpr::AO__atomic_store ||
                  E->getOp() == AtomicExpr::AO__atomic_store_n;
   bool IsLoad = E->getOp() == AtomicExpr::AO__c11_atomic_load ||
+                E->getOp() == AtomicExpr::AO__opencl_atomic_load ||
                 E->getOp() == AtomicExpr::AO__atomic_load ||
                 E->getOp() == AtomicExpr::AO__atomic_load_n;
 
+  assert(isa<llvm::ConstantInt>(Scope) &&
+      "Non-constant synchronization scope not supported");
+  auto SCID = getTargetHooks().getLLVMSyncScopeID(
+      static_cast<SyncScope>(cast<llvm::ConstantInt>(Scope)->getZExtValue()),
+      getLLVMContext());
+
   if (isa<llvm::ConstantInt>(Order)) {
     auto ord = cast<llvm::ConstantInt>(Order)->getZExtValue();
     // We should not ever get to a case where the ordering isn't a valid C ABI
@@ -1032,30 +1146,30 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
       switch ((llvm::AtomicOrderingCABI)ord) {
       case llvm::AtomicOrderingCABI::relaxed:
         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
-                     llvm::AtomicOrdering::Monotonic);
+                     llvm::AtomicOrdering::Monotonic, SCID);
         break;
       case llvm::AtomicOrderingCABI::consume:
       case llvm::AtomicOrderingCABI::acquire:
         if (IsStore)
           break; // Avoid crashing on code with undefined behavior
         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
-                     llvm::AtomicOrdering::Acquire);
+                     llvm::AtomicOrdering::Acquire, SCID);
         break;
       case llvm::AtomicOrderingCABI::release:
         if (IsLoad)
           break; // Avoid crashing on code with undefined behavior
         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
-                     llvm::AtomicOrdering::Release);
+                     llvm::AtomicOrdering::Release, SCID);
         break;
       case llvm::AtomicOrderingCABI::acq_rel:
         if (IsLoad || IsStore)
           break; // Avoid crashing on code with undefined behavior
         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
-                     llvm::AtomicOrdering::AcquireRelease);
+                     llvm::AtomicOrdering::AcquireRelease, SCID);
         break;
       case llvm::AtomicOrderingCABI::seq_cst:
         EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
-                     llvm::AtomicOrdering::SequentiallyConsistent);
+                     llvm::AtomicOrdering::SequentiallyConsistent, SCID);
         break;
       }
     if (RValTy->isVoidType())
@@ -1091,13 +1205,13 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
 
   // Emit all the different atomics
   Builder.SetInsertPoint(MonotonicBB);
-  EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
-               Size, llvm::AtomicOrdering::Monotonic);
+  EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
+               llvm::AtomicOrdering::Monotonic, SCID);
   Builder.CreateBr(ContBB);
   if (!IsStore) {
     Builder.SetInsertPoint(AcquireBB);
-    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
-                 Size, llvm::AtomicOrdering::Acquire);
+    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
+                 llvm::AtomicOrdering::Acquire, SCID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::consume),
                 AcquireBB);
@@ -1106,23 +1220,23 @@ RValue CodeGenFunction::EmitAtomicExpr(AtomicExpr *E) {
   }
   if (!IsLoad) {
     Builder.SetInsertPoint(ReleaseBB);
-    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
-                 Size, llvm::AtomicOrdering::Release);
+    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
+                 llvm::AtomicOrdering::Release, SCID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::release),
                 ReleaseBB);
   }
   if (!IsLoad && !IsStore) {
     Builder.SetInsertPoint(AcqRelBB);
-    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
-                 Size, llvm::AtomicOrdering::AcquireRelease);
+    EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
+                 llvm::AtomicOrdering::AcquireRelease, SCID);
     Builder.CreateBr(ContBB);
     SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::acq_rel),
                 AcqRelBB);
   }
   Builder.SetInsertPoint(SeqCstBB);
-  EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail,
-               Size, llvm::AtomicOrdering::SequentiallyConsistent);
+  EmitAtomicOp(*this, E, Dest, Ptr, Val1, Val2, IsWeak, OrderFail, Size,
+               llvm::AtomicOrdering::SequentiallyConsistent, SCID);
   Builder.CreateBr(ContBB);
   SI->addCase(Builder.getInt32((int)llvm::AtomicOrderingCABI::seq_cst),
               SeqCstBB);
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index ec48b2cc86..cd7911a604 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -48,7 +48,7 @@ using namespace CodeGen;
 
 llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
   unsigned addressSpace =
-    cast<llvm::PointerType>(value->getType())->getAddressSpace();
+      cast<llvm::PointerType>(value->getType())->getAddressSpace();
 
   llvm::PointerType *destType = Int8PtrTy;
   if (addressSpace)
diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index 12341431ac..d2fcbeadbc 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -444,6 +444,11 @@ TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
   return llvm::ConstantExpr::getPointerCast(Src, DestTy);
 }
 
+llvm::SyncScope::ID
+TargetCodeGenInfo::getLLVMSyncScopeID(SyncScope S, llvm::LLVMContext &C) const {
+  return C.getOrInsertSyncScopeID(""); /* default sync scope */
+}
+
 static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays);
 
 /// isEmptyField - Return true iff a the field is "empty", that is it
@@ -7430,6 +7435,8 @@ public:
   }
   unsigned getGlobalVarAddressSpace(CodeGenModule &CGM,
                                     const VarDecl *D) const override;
+  llvm::SyncScope::ID getLLVMSyncScopeID(SyncScope S,
+                                         llvm::LLVMContext &C) const override;
 };
 }
 
@@ -7539,6 +7546,26 @@ AMDGPUTargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
   return DefaultGlobalAS;
 }
 
+llvm::SyncScope::ID
+AMDGPUTargetCodeGenInfo::getLLVMSyncScopeID(SyncScope S,
+                                            llvm::LLVMContext &C) const {
+  StringRef Name;
+  switch (S) {
+  case SyncScope::OpenCLWorkGroup:
+    Name = "workgroup";
+    break;
+  case SyncScope::OpenCLDevice:
+    Name = "agent";
+    break;
+  case SyncScope::OpenCLAllSVMDevices:
+    Name = "";
+    break;
+  case SyncScope::OpenCLSubGroup:
+    Name = "subgroup";
+  }
+  return C.getOrInsertSyncScopeID(Name);
+}
+
 //===----------------------------------------------------------------------===//
 // SPARC v8 ABI Implementation.
 // Based on the SPARC Compliance Definition version 2.4.1.
diff --git a/lib/CodeGen/TargetInfo.h b/lib/CodeGen/TargetInfo.h
index 7149dec1da..c26d7c710c 100644
--- a/lib/CodeGen/TargetInfo.h
+++ b/lib/CodeGen/TargetInfo.h
@@ -19,6 +19,7 @@
 #include "CGValue.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/SyncScope.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 
@@ -260,6 +261,10 @@ public:
   virtual llvm::Constant *
   performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *V, unsigned SrcAddr,
                        unsigned DestAddr, llvm::Type *DestTy) const;
+
+  /// Get the syncscope used in LLVM IR.
+  virtual llvm::SyncScope::ID getLLVMSyncScopeID(SyncScope S,
+                                                 llvm::LLVMContext &C) const;
 };
 
 } // namespace CodeGen