CodeGen: Have 'this'-returning constructors and destructors to take advantage of the new backend 'returned' attribute.

The backend will now use the generic 'returned' attribute to form tail calls where possible, as well as avoid save-restores of 'this' in some cases (specifically the cases that matter for the ARM C++ ABI).

This patch also reverts a prior front-end only partial implementation of these optimizations, since it's no longer required.

llvm-svn: 184205

1 files changed, 6 insertions, 6 deletions

diff --git a/clang/test/CodeGenCXX/microsoft-abi-structors.cpp b/clang/test/CodeGenCXX/microsoft-abi-structors.cpp
index 864540d425e..2c2f162540f 100644
--- a/clang/test/CodeGenCXX/microsoft-abi-structors.cpp
+++ b/clang/test/CodeGenCXX/microsoft-abi-structors.cpp
@@ -15,7 +15,7 @@ class A {
 void no_constructor_destructor_infinite_recursion() {
   A a;
 
-// CHECK:      define linkonce_odr x86_thiscallcc %"class.basic::A"* @"\01??0A@basic@@QAE@XZ"(%"class.basic::A"* %this)
+// CHECK:      define linkonce_odr x86_thiscallcc %"class.basic::A"* @"\01??0A@basic@@QAE@XZ"(%"class.basic::A"* returned %this)
 // CHECK:        [[THIS_ADDR:%[.0-9A-Z_a-z]+]] = alloca %"class.basic::A"*, align 4
 // CHECK-NEXT:   store %"class.basic::A"* %this, %"class.basic::A"** [[THIS_ADDR]], align 4
 // CHECK-NEXT:   [[T1:%[.0-9A-Z_a-z]+]] = load %"class.basic::A"** [[THIS_ADDR]]
@@ -34,7 +34,7 @@ struct B {
 
 // Tests that we can define constructors outside the class (PR12784).
 B::B() {
-  // CHECK: define x86_thiscallcc %"struct.basic::B"* @"\01??0B@basic@@QAE@XZ"(%"struct.basic::B"* %this)
+  // CHECK: define x86_thiscallcc %"struct.basic::B"* @"\01??0B@basic@@QAE@XZ"(%"struct.basic::B"* returned %this)
   // CHECK: ret
 }
 
@@ -136,7 +136,7 @@ struct B : A {
 };
 
 B::B() {
-  // CHECK: define x86_thiscallcc %"struct.constructors::B"* @"\01??0B@constructors@@QAE@XZ"(%"struct.constructors::B"* %this)
+  // CHECK: define x86_thiscallcc %"struct.constructors::B"* @"\01??0B@constructors@@QAE@XZ"(%"struct.constructors::B"* returned %this)
   // CHECK: call x86_thiscallcc %"struct.constructors::A"* @"\01??0A@constructors@@QAE@XZ"(%"struct.constructors::A"* %{{.*}})
   // CHECK: ret
 }
@@ -146,7 +146,7 @@ struct C : virtual A {
 };
 
 C::C() {
-  // CHECK: define x86_thiscallcc %"struct.constructors::C"* @"\01??0C@constructors@@QAE@XZ"(%"struct.constructors::C"* %this, i32 %is_most_derived)
+  // CHECK: define x86_thiscallcc %"struct.constructors::C"* @"\01??0C@constructors@@QAE@XZ"(%"struct.constructors::C"* returned %this, i32 %is_most_derived)
   // TODO: make sure this works in the Release build too;
   // CHECK: store i32 %is_most_derived, i32* %[[IS_MOST_DERIVED_VAR:.*]], align 4
   // CHECK: %[[IS_MOST_DERIVED_VAL:.*]] = load i32* %[[IS_MOST_DERIVED_VAR]]
@@ -175,7 +175,7 @@ struct D : C {
 };
 
 D::D() {
-  // CHECK: define x86_thiscallcc %"struct.constructors::D"* @"\01??0D@constructors@@QAE@XZ"(%"struct.constructors::D"* %this, i32 %is_most_derived) unnamed_addr
+  // CHECK: define x86_thiscallcc %"struct.constructors::D"* @"\01??0D@constructors@@QAE@XZ"(%"struct.constructors::D"* returned %this, i32 %is_most_derived) unnamed_addr
   // CHECK: store i32 %is_most_derived, i32* %[[IS_MOST_DERIVED_VAR:.*]], align 4
   // CHECK: %[[IS_MOST_DERIVED_VAL:.*]] = load i32* %[[IS_MOST_DERIVED_VAR]]
   // CHECK: %[[SHOULD_CALL_VBASE_CTORS:.*]] = icmp ne i32 %[[IS_MOST_DERIVED_VAL]], 0
@@ -196,7 +196,7 @@ struct E : virtual C {
 };
 
 E::E() {
-  // CHECK: define x86_thiscallcc %"struct.constructors::E"* @"\01??0E@constructors@@QAE@XZ"(%"struct.constructors::E"* %this, i32 %is_most_derived) unnamed_addr
+  // CHECK: define x86_thiscallcc %"struct.constructors::E"* @"\01??0E@constructors@@QAE@XZ"(%"struct.constructors::E"* returned %this, i32 %is_most_derived) unnamed_addr
   // CHECK: store i32 %is_most_derived, i32* %[[IS_MOST_DERIVED_VAR:.*]], align 4
   // CHECK: %[[IS_MOST_DERIVED_VAL:.*]] = load i32* %[[IS_MOST_DERIVED_VAR]]
   // CHECK: %[[SHOULD_CALL_VBASE_CTORS:.*]] = icmp ne i32 %[[IS_MOST_DERIVED_VAL]], 0