r323712 - [coroutines] Fix application of NRVO to Coroutine "Gro" or return object.
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 29 15:52:57 PST 2018
Author: ericwf
Date: Mon Jan 29 15:52:57 2018
New Revision: 323712
URL: http://llvm.org/viewvc/llvm-project?rev=323712&view=rev
Log:
[coroutines] Fix application of NRVO to Coroutine "Gro" or return object.
Summary:
Fix NRVO for Gro variable.
Previously, we only marked the GRO declaration as an NRVO variable
when its QualType and the function return's QualType matched exactly
(using operator==). However, this was incorrect for two reasons:
1. We were marking non-class types, such as ints, as being NRVO variables.
2. We failed to handle cases where the canonical types were the same, but the actual `QualType` objects were different. For example, if one was represented by a typedef. (Example: https://godbolt.org/g/3UFgsL)
This patch fixes these bugs by marking the Gro variable as supporting NRVO only
when `BuildReturnStmt` marks the Gro variable as a coroutine candidate.
Reviewers: rsmith, GorNishanov, nicholas
Reviewed By: GorNishanov
Subscribers: majnemer, cfe-commits
Differential Revision: https://reviews.llvm.org/D42343
Added:
cfe/trunk/test/CodeGenCoroutines/coro-gro-nrvo.cpp
Modified:
cfe/trunk/lib/Sema/SemaCoroutine.cpp
cfe/trunk/test/CodeGenCoroutines/coro-alloc.cpp
Modified: cfe/trunk/lib/Sema/SemaCoroutine.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCoroutine.cpp?rev=323712&r1=323711&r2=323712&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaCoroutine.cpp (original)
+++ cfe/trunk/lib/Sema/SemaCoroutine.cpp Mon Jan 29 15:52:57 2018
@@ -1316,10 +1316,6 @@ bool CoroutineStmtBuilder::makeGroDeclAn
if (Res.isInvalid())
return false;
- if (GroType == FnRetType) {
- GroDecl->setNRVOVariable(true);
- }
-
S.AddInitializerToDecl(GroDecl, Res.get(),
/*DirectInit=*/false);
@@ -1343,6 +1339,8 @@ bool CoroutineStmtBuilder::makeGroDeclAn
noteMemberDeclaredHere(S, ReturnValue, Fn);
return false;
}
+ if (cast<clang::ReturnStmt>(ReturnStmt.get())->getNRVOCandidate() == GroDecl)
+ GroDecl->setNRVOVariable(true);
this->ReturnStmt = ReturnStmt.get();
return true;
Modified: cfe/trunk/test/CodeGenCoroutines/coro-alloc.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCoroutines/coro-alloc.cpp?rev=323712&r1=323711&r2=323712&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCoroutines/coro-alloc.cpp (original)
+++ cfe/trunk/test/CodeGenCoroutines/coro-alloc.cpp Mon Jan 29 15:52:57 2018
@@ -173,6 +173,7 @@ struct std::experimental::coroutine_trai
// CHECK-LABEL: f4(
extern "C" int f4(promise_on_alloc_failure_tag) {
// CHECK: %[[RetVal:.+]] = alloca i32
+ // CHECK: %[[Gro:.+]] = alloca i32
// CHECK: %[[ID:.+]] = call token @llvm.coro.id(i32 16
// CHECK: %[[SIZE:.+]] = call i64 @llvm.coro.size.i64()
// CHECK: %[[MEM:.+]] = call i8* @_ZnwmRKSt9nothrow_t(i64 %[[SIZE]], %"struct.std::nothrow_t"* dereferenceable(1) @_ZStL7nothrow)
@@ -186,7 +187,12 @@ extern "C" int f4(promise_on_alloc_failu
// CHECK: [[OKBB]]:
// CHECK: %[[OkRet:.+]] = call i32 @_ZNSt12experimental16coroutine_traitsIJi28promise_on_alloc_failure_tagEE12promise_type17get_return_objectEv(
- // CHECK: store i32 %[[OkRet]], i32* %[[RetVal]]
+ // CHECK: store i32 %[[OkRet]], i32* %[[Gro]]
+
+ // CHECK: coro.ret:
+ // CHECK: %[[Tmp1:.*]] = load i32, i32* %[[Gro]]
+ // CHECK-NEXT: store i32 %[[Tmp1]], i32* %[[RetVal]]
+ // CHECK-NEXT: br label %[[RetBB]]
// CHECK: [[RetBB]]:
// CHECK: %[[LoadRet:.+]] = load i32, i32* %[[RetVal]], align 4
Added: cfe/trunk/test/CodeGenCoroutines/coro-gro-nrvo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCoroutines/coro-gro-nrvo.cpp?rev=323712&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCoroutines/coro-gro-nrvo.cpp (added)
+++ cfe/trunk/test/CodeGenCoroutines/coro-gro-nrvo.cpp Mon Jan 29 15:52:57 2018
@@ -0,0 +1,80 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fcoroutines-ts -std=c++14 -emit-llvm %s -o - -disable-llvm-passes | FileCheck %s
+
+#include "Inputs/coroutine.h"
+
+using namespace std::experimental;
+
+namespace std {
+
+struct nothrow_t {};
+constexpr nothrow_t nothrow = {};
+
+} // end namespace std
+
+// Required when get_return_object_on_allocation_failure() is defined by
+// the promise.
+void* operator new(__SIZE_TYPE__ __sz, const std::nothrow_t&) noexcept;
+void operator delete(void* __p, const std::nothrow_t&) noexcept;
+
+
+template <class RetObject>
+struct promise_type {
+ RetObject get_return_object();
+ suspend_always initial_suspend();
+ suspend_never final_suspend();
+ void return_void();
+ static void unhandled_exception();
+};
+
+struct coro {
+ using promise_type = promise_type<coro>;
+ coro(coro const&);
+ struct Impl;
+ Impl *impl;
+};
+
+// Verify that the NRVO is applied to the Gro object.
+// CHECK-LABEL: define void @_Z1fi(%struct.coro* noalias sret %agg.result, i32)
+coro f(int) {
+// CHECK: coro.init:
+// CHECK: store i1 false, i1* %gro.active
+// CHECK-NEXT: call void @{{.*get_return_objectEv}}(%struct.coro* sret %agg.result
+// CHECK-NEXT: store i1 true, i1* %gro.active
+ co_return;
+}
+
+
+template <class RetObject>
+struct promise_type_with_on_alloc_failure {
+ static RetObject get_return_object_on_allocation_failure();
+ RetObject get_return_object();
+ suspend_always initial_suspend();
+ suspend_never final_suspend();
+ void return_void();
+ static void unhandled_exception();
+};
+
+struct coro_two {
+ using promise_type = promise_type_with_on_alloc_failure<coro_two>;
+ coro_two(coro_two const&);
+ struct Impl;
+ Impl *impl;
+};
+
+// Verify that the NRVO is applied to the Gro object.
+// CHECK-LABEL: define void @_Z1hi(%struct.coro_two* noalias sret %agg.result, i32)
+ coro_two h(int) {
+
+// CHECK: coro.ret.on.failure:
+// CHECK-NEXT: call void @{{.*get_return_object_on_allocation_failureEv}}(%struct.coro_two* sret %agg.result
+// CHECK-NEXT: br label %[[RetLabel:.*]]
+
+// CHECK: coro.init:
+// CHECK: store i1 false, i1* %gro.active
+// CHECK-NEXT: call void @{{.*get_return_objectEv}}(%struct.coro_two* sret %agg.result
+// CHECK-NEXT: store i1 true, i1* %gro.active
+
+// CHECK: [[RetLabel]]:
+// CHECK-NEXT: ret void
+ co_return;
+}
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