Index: lib/CodeGen/CGCoroutine.cpp
===================================================================
--- lib/CodeGen/CGCoroutine.cpp
+++ lib/CodeGen/CGCoroutine.cpp
@@ -57,6 +57,11 @@
   // builtin.
   llvm::CallInst *CoroId = nullptr;
 
+  // Stores the llvm.coro.begin emitted in the function so that we can replace
+  // all coro.frame intrinsics with direct SSA value of coro.begin that returns
+  // the address of the coroutine frame of the current coroutine.
+  llvm::CallInst *CoroBegin = nullptr;
+
   // If coro.id came from the builtin, remember the expression to give better
   // diagnostic. If CoroIdExpr is nullptr, the coro.id was created by
   // EmitCoroutineBody.
@@ -330,8 +335,9 @@
   auto *Phi = Builder.CreatePHI(VoidPtrTy, 2);
   Phi->addIncoming(NullPtr, EntryBB);
   Phi->addIncoming(AllocateCall, AllocOrInvokeContBB);
-  Builder.CreateCall(
+  auto *CoroBegin = Builder.CreateCall(
       CGM.getIntrinsic(llvm::Intrinsic::coro_begin), {CoroId, Phi});
+  CurCoro.Data->CoroBegin = CoroBegin;
 
   CurCoro.Data->CleanupJD = getJumpDestInCurrentScope(RetBB);
   {
@@ -388,6 +394,17 @@
   switch (IID) {
   default:
     break;
+  // The coro.frame builtin is replaced with an SSA value of the coro.begin
+  // intrinsic.
+  case llvm::Intrinsic::coro_frame: {
+    if (CurCoro.Data && CurCoro.Data->CoroBegin) {
+      return RValue::get(CurCoro.Data->CoroBegin);
+    }
+    CGM.Error(E->getLocStart(), "this builtin expect that __builtin_coro_begin "
+      "has been used earlier in this function");
+    auto NullPtr = llvm::ConstantPointerNull::get(Builder.getInt8PtrTy());
+    return RValue::get(NullPtr);
+  }
   // The following three intrinsics take a token parameter referring to a token
   // returned by earlier call to @llvm.coro.id. Since we cannot represent it in
   // builtins, we patch it up here.
@@ -414,10 +431,16 @@
   llvm::Value *F = CGM.getIntrinsic(IID);
   llvm::CallInst *Call = Builder.CreateCall(F, Args);
 
+  // Note: The following code is to enable to emit coroutine intrinsics by
+  // hand to experiment with coroutines in C.
   // If we see @llvm.coro.id remember it in the CoroData. We will update
   // coro.alloc, coro.begin and coro.free intrinsics to refer to it.
   if (IID == llvm::Intrinsic::coro_id) {
     createCoroData(*this, CurCoro, Call, E);
   }
+  else if (IID == llvm::Intrinsic::coro_begin) {
+    if (CurCoro.Data)
+      CurCoro.Data->CoroBegin = Call;
+  }
   return RValue::get(Call);
 }
Index: test/CodeGenCoroutines/coro-alloc.cpp
===================================================================
--- test/CodeGenCoroutines/coro-alloc.cpp
+++ test/CodeGenCoroutines/coro-alloc.cpp
@@ -66,9 +66,8 @@
 
   // CHECK: [[InitBB]]:
   // CHECK: %[[PHI:.+]] = phi i8* [ null, %{{.+}} ], [ %call, %[[AllocBB]] ]
-  // CHECK: call i8* @llvm.coro.begin(token %[[ID]], i8* %[[PHI]])
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(token %[[ID]], i8* %[[PHI]])
 
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
   // CHECK: %[[MEM:.+]] = call i8* @llvm.coro.free(token %[[ID]], i8* %[[FRAME]])
   // CHECK: call void @_ZdlPv(i8* %[[MEM]])
   co_return;
@@ -93,7 +92,7 @@
   // CHECK: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
   // CHECK: call i8* @_ZNSt12experimental16coroutine_traitsIJv15promise_new_tagEE12promise_typenwEm(i64 %[[SIZE]])
 
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
   // CHECK: %[[MEM:.+]] = call i8* @llvm.coro.free(token %[[ID]], i8* %[[FRAME]])
   // CHECK: call void @_ZdlPv(i8* %[[MEM]])
   co_return;
@@ -118,7 +117,7 @@
   // CHECK: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
   // CHECK: call i8* @_Znwm(i64 %[[SIZE]])
 
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
   // CHECK: %[[MEM:.+]] = call i8* @llvm.coro.free(token %[[ID]], i8* %[[FRAME]])
   // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJv18promise_delete_tagEE12promise_typedlEPv(i8* %[[MEM]])
   co_return;
@@ -143,7 +142,7 @@
   // CHECK: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
   // CHECK: call i8* @_Znwm(i64 %[[SIZE]])
 
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
   // CHECK: %[[MEM:.+]] = call i8* @llvm.coro.free(token %[[ID]], i8* %[[FRAME]])
   // CHECK: %[[SIZE2:.+]] = call i64 @llvm.coro.size.i64()
   // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJv24promise_sized_delete_tagEE12promise_typedlEPvm(i8* %[[MEM]], i64 %[[SIZE2]])
Index: test/CodeGenCoroutines/coro-await.cpp
===================================================================
--- test/CodeGenCoroutines/coro-await.cpp
+++ test/CodeGenCoroutines/coro-await.cpp
@@ -40,6 +40,7 @@
 
 // CHECK-LABEL: f0(
 extern "C" void f0() {
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
 
   co_await suspend_always{};
   // See if we need to suspend:
@@ -54,7 +55,6 @@
   // ---------------------------
   // Build the coroutine handle and pass it to await_suspend
   // ---------------------------
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
   // CHECK: call i8* @_ZNSt12experimental16coroutine_handleINS_16coroutine_traitsIJvEE12promise_typeEE12from_addressEPv(i8* %[[FRAME]])
   //   ... many lines of code to coerce coroutine_handle into an i8* scalar
   // CHECK: %[[CH:.+]] = load i8*, i8** %{{.+}}
@@ -100,8 +100,9 @@
 
 // CHECK-LABEL: f1(
 extern "C" void f1(int) {
-  co_yield 42;
   // CHECK: %[[PROMISE:.+]] = alloca %"struct.std::experimental::coroutine_traits<void, int>::promise_type"
+  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
+  co_yield 42;
   // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJviEE12promise_type11yield_valueEi(%struct.suspend_maybe* sret %[[AWAITER:.+]], %"struct.std::experimental::coroutine_traits<void, int>::promise_type"* %[[PROMISE]], i32 42)
 
   // See if we need to suspend:
@@ -116,7 +117,6 @@
   // ---------------------------
   // Build the coroutine handle and pass it to await_suspend
   // ---------------------------
-  // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
   // CHECK: call i8* @_ZNSt12experimental16coroutine_handleINS_16coroutine_traitsIJviEE12promise_typeEE12from_addressEPv(i8* %[[FRAME]])
   //   ... many lines of code to coerce coroutine_handle into an i8* scalar
   // CHECK: %[[CH:.+]] = load i8*, i8** %{{.+}}
Index: test/CodeGenCoroutines/coro-builtins.c
===================================================================
--- test/CodeGenCoroutines/coro-builtins.c
+++ test/CodeGenCoroutines/coro-builtins.c
@@ -2,7 +2,7 @@
 
 void *myAlloc(long long);
 
-// CHECK-LABEL: f( 
+// CHECK-LABEL: f(
 void f(int n) {
   // CHECK: %n.addr = alloca i32
   // CHECK: %n_copy = alloca i32
@@ -19,31 +19,25 @@
 
   // CHECK-NEXT: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
   // CHECK-NEXT: %[[MEM:.+]] = call i8* @myAlloc(i64 %[[SIZE]])
-  // CHECK-NEXT: %[[BEG:.+]] = call i8* @llvm.coro.begin(token %[[COROID]], i8* %[[MEM]])
+  // CHECK-NEXT: %[[FRAME:.+]] = call i8* @llvm.coro.begin(token %[[COROID]], i8* %[[MEM]])
   __builtin_coro_begin(myAlloc(__builtin_coro_size()));
 
-  // CHECK-NEXT: %[[FRAME1:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call void @llvm.coro.resume(i8* %[[FRAME1]])
+  // CHECK-NEXT: call void @llvm.coro.resume(i8* %[[FRAME]])
   __builtin_coro_resume(__builtin_coro_frame());
 
-  // CHECK-NEXT: %[[FRAME2:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call void @llvm.coro.destroy(i8* %[[FRAME2]])
+  // CHECK-NEXT: call void @llvm.coro.destroy(i8* %[[FRAME]])
   __builtin_coro_destroy(__builtin_coro_frame());
 
-  // CHECK-NEXT: %[[FRAME3:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call i1 @llvm.coro.done(i8* %[[FRAME3]])
+  // CHECK-NEXT: call i1 @llvm.coro.done(i8* %[[FRAME]])
   __builtin_coro_done(__builtin_coro_frame());
 
-  // CHECK-NEXT: %[[FRAME4:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call i8* @llvm.coro.promise(i8* %[[FRAME4]], i32 48, i1 false)
+  // CHECK-NEXT: call i8* @llvm.coro.promise(i8* %[[FRAME]], i32 48, i1 false)
   __builtin_coro_promise(__builtin_coro_frame(), 48, 0);
 
-  // CHECK-NEXT: %[[FRAME5:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call i8* @llvm.coro.free(token %[[COROID]], i8* %[[FRAME5]])
+  // CHECK-NEXT: call i8* @llvm.coro.free(token %[[COROID]], i8* %[[FRAME]])
   __builtin_coro_free(__builtin_coro_frame());
 
-  // CHECK-NEXT: %[[FRAME6:.+]] = call i8* @llvm.coro.frame() 
-  // CHECK-NEXT: call i1 @llvm.coro.end(i8* %[[FRAME6]], i1 false)
+  // CHECK-NEXT: call i1 @llvm.coro.end(i8* %[[FRAME]], i1 false)
   __builtin_coro_end(__builtin_coro_frame(), 0);
 
   // CHECK-NEXT: call i8 @llvm.coro.suspend(token none, i1 true)