clang/test/CodeGenCoroutines/coro-elide-thinlto.cpp

   1 // REQUIRES: x86_64-linux
   2 // This tests that the coroutine elide optimization could happen succesfully with ThinLTO.
   3 // This test is adapted from coro-elide.cpp and splits functions into two files.
   4 //
   5 // RUN: split-file %s %t
   6 // RUN: %clang --target=x86_64-linux -std=c++20 -O2 -flto=thin -I %S -c %t/coro-elide-callee.cpp -o %t/coro-elide-callee.bc
   7 // RUN: %clang --target=x86_64-linux -std=c++20 -O2 -flto=thin -I %S -c %t/coro-elide-caller.cpp -o %t/coro-elide-caller.bc
   8 // RUN: llvm-lto --thinlto %t/coro-elide-callee.bc %t/coro-elide-caller.bc -o %t/summary
   9 // RUN: %clang_cc1 -O2 -x ir %t/coro-elide-caller.bc -fthinlto-index=%t/summary.thinlto.bc -emit-llvm -o - | FileCheck %s
  10
  11 //--- coro-elide-task.h
  12 #pragma once
  13 #include "Inputs/coroutine.h"
  14
  15 struct Task {
  16   struct promise_type {
  17     struct FinalAwaiter {
  18       bool await_ready() const noexcept { return false; }
  19       template <typename PromiseType>
  20       std::coroutine_handle<> await_suspend(std::coroutine_handle<PromiseType> h) noexcept {
  21         if (!h)
  22           return std::noop_coroutine();
  23         return h.promise().continuation;
  24       }
  25       void await_resume() noexcept {}
  26     };
  27     Task get_return_object() noexcept {
  28       return std::coroutine_handle<promise_type>::from_promise(*this);
  29     }
  30     std::suspend_always initial_suspend() noexcept { return {}; }
  31     FinalAwaiter final_suspend() noexcept { return {}; }
  32     void unhandled_exception() noexcept {}
  33     void return_value(int x) noexcept {
  34       _value = x;
  35     }
  36     std::coroutine_handle<> continuation;
  37     int _value;
  38   };
  39
  40   Task(std::coroutine_handle<promise_type> handle) : handle(handle) {}
  41   ~Task() {
  42     if (handle)
  43       handle.destroy();
  44   }
  45
  46   struct Awaiter {
  47     bool await_ready() const noexcept { return false; }
  48     void await_suspend(std::coroutine_handle<void> continuation) noexcept {}
  49     int await_resume() noexcept {
  50       return 43;
  51     }
  52   };
  53
  54   auto operator co_await() {
  55     return Awaiter{};
  56   }
  57
  58 private:
  59   std::coroutine_handle<promise_type> handle;
  60 };
  61
  62 //--- coro-elide-callee.cpp
  63 #include "coro-elide-task.h"
  64 Task task0() {
  65   co_return 43;
  66 }
  67
  68 //--- coro-elide-caller.cpp
  69 #include "coro-elide-task.h"
  70
  71 Task task0();
  72
  73 Task task1() {
  74   co_return co_await task0();
  75 }
  76
  77 // CHECK-LABEL: define{{.*}} void @_Z5task1v.resume
  78 // CHECK-NOT: {{.*}}_Znwm