[coroutines] Add co_return statement emission

Summary:
Added co_return statement emission.

Tweaked coro-alloc.cpp test to use co_return to trigger coroutine processing instead of co_await, since this change starts emitting the body of the coroutine and await expression handling has not been upstreamed yet.

Reviewers: rsmith, majnemer, EricWF, aaron.ballman

Reviewed By: rsmith

Subscribers: majnemer, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D29979

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@297076 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 57 insertions, 5 deletions

diff --git a/test/CodeGenCoroutines/coro-alloc.cpp b/test/CodeGenCoroutines/coro-alloc.cpp
index 7dbbdd31be..87da7aed89 100644
--- a/test/CodeGenCoroutines/coro-alloc.cpp
+++ b/test/CodeGenCoroutines/coro-alloc.cpp
@@ -34,7 +34,7 @@ extern "C" void f0(global_new_delete_tag) {
   // 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_await suspend_always{};
+  co_return;
 }
 
 struct promise_new_tag {};
@@ -59,7 +59,7 @@ extern "C" void f1(promise_new_tag ) {
   // 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_await suspend_always{};
+  co_return;
 }
 
 struct promise_delete_tag {};
@@ -84,7 +84,7 @@ extern "C" void f2(promise_delete_tag) {
   // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.frame()
   // CHECK: %[[MEM:.+]] = call i8* @llvm.coro.free(token %[[ID]], i8* %[[FRAME]])
   // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJv18promise_delete_tagEE12promise_typedlEPv(i8* %[[MEM]])
-  co_await suspend_always{};
+  co_return;
 }
 
 struct promise_sized_delete_tag {};
@@ -100,7 +100,7 @@ struct std::experimental::coroutine_traits<void, promise_sized_delete_tag> {
   };
 };
 
-// CHECK-LABEL: f3( 
+// CHECK-LABEL: f3(
 extern "C" void f3(promise_sized_delete_tag) {
   // CHECK: %[[ID:.+]] = call token @llvm.coro.id(i32 16
   // CHECK: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
@@ -110,5 +110,5 @@ extern "C" void f3(promise_sized_delete_tag) {
   // 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]])
-  co_await suspend_always{};
+  co_return;
 }
diff --git a/test/CodeGenCoroutines/coro-return.cpp b/test/CodeGenCoroutines/coro-return.cpp
new file mode 100644
index 0000000000..2b94da8336
--- /dev/null
+++ b/test/CodeGenCoroutines/coro-return.cpp
@@ -0,0 +1,52 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fcoroutines-ts -std=c++14 -emit-llvm %s -o - -disable-llvm-passes | FileCheck %s
+
+namespace std {
+namespace experimental {
+template <typename... T>
+struct coroutine_traits;
+}
+}
+
+struct suspend_always {
+  bool await_ready();
+  void await_suspend();
+  void await_resume();
+};
+
+template<>
+struct std::experimental::coroutine_traits<void> {
+  struct promise_type {
+    void get_return_object();
+    suspend_always initial_suspend();
+    suspend_always final_suspend();
+    void return_void();
+  };
+};
+
+// CHECK-LABEL: f0(
+extern "C" void f0() {
+  // CHECK: %__promise = alloca %"struct.std::experimental::coroutine_traits<void>::promise_type"
+  // CHECK: %call = call i8* @_Znwm(
+  // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJvEE12promise_type11return_voidEv(%"struct.std::experimental::coroutine_traits<void>::promise_type"* %__promise)
+  // CHECK: call void @_ZdlPv
+  co_return;
+}
+
+template<>
+struct std::experimental::coroutine_traits<int> {
+  struct promise_type {
+    int get_return_object();
+    suspend_always initial_suspend();
+    suspend_always final_suspend();
+    void return_value(int);
+  };
+};
+
+// CHECK-LABEL: f1(
+extern "C" int f1() {
+  // CHECK: %__promise = alloca %"struct.std::experimental::coroutine_traits<int>::promise_type"
+  // CHECK: %call = call i8* @_Znwm(
+  // CHECK: call void @_ZNSt12experimental16coroutine_traitsIJiEE12promise_type12return_valueEi(%"struct.std::experimental::coroutine_traits<int>::promise_type"* %__promise, i32 42)
+  // CHECK: call void @_ZdlPv
+  co_return 42;
+}