clang/test/CodeGenCXX/ctor-empty-nounique.cpp

   1 // RUN: %clang_cc1 -triple x86_64-windows-gnu -emit-llvm -o - %s | FileCheck %s
   2 // RUN: %clang_cc1 -triple powerpc64le-windows-gnu -emit-llvm -o - %s | FileCheck %s
   3
   4 // An empty struct is handled as a struct with a dummy i8, on all targets.
   5 // Most targets treat an empty struct return value as essentially void - but
   6 // some don't. (Currently, at least x86_64-windows-* and powerpc64le-* don't
   7 // treat it as void.)
   8 //
   9 // When intializing a struct with such a no_unique_address member, make sure we
  10 // don't write the dummy i8 into the struct where there's no space allocated for
  11 // it.
  12 //
  13 // This can only be tested with targets that don't treat empty struct returns as
  14 // void.
  15
  16 struct S {};
  17 S f();
  18 struct Z {
  19   int x;
  20   [[no_unique_address]] S y;
  21   Z();
  22 };
  23 Z::Z() : x(111), y(f()) {}
  24
  25 // CHECK: define {{.*}} @_ZN1ZC2Ev
  26 // CHECK: %call = call i8 @_Z1fv()
  27 // CHECK-NEXT: ret void
  28
  29
  30 // Check that the constructor for an empty member gets called with the right
  31 // 'this' pointer.
  32
  33 struct S2 {
  34   S2();
  35 };
  36 struct Z2 {
  37   int x;
  38   [[no_unique_address]] S2 y;
  39   Z2();
  40 };
  41 Z2::Z2() : x(111) {}
  42
  43 // CHECK: define {{.*}} @_ZN2Z2C2Ev(ptr {{.*}} %this)
  44 // CHECK: %this.addr = alloca ptr
  45 // CHECK: store ptr %this, ptr %this.addr
  46 // CHECK: %this1 = load ptr, ptr %this.addr
  47 // CHECK: call void @_ZN2S2C1Ev(ptr {{.*}} %this1)