clang/test/CodeGenCXX/init-invariant.cpp

   1 // RUN: %clang_cc1 -triple i686-linux-gnu -std=c++20 -emit-llvm %s -disable-llvm-passes -o - | FileCheck %s --check-prefix=CHECK-O0
   2 // RUN: %clang_cc1 -triple i686-linux-gnu -std=c++20 -emit-llvm %s -O1 -disable-llvm-passes -o - | FileCheck %s
   3
   4 // Check that we add an llvm.invariant.start.p0i8 to mark when a global becomes
   5 // read-only. If globalopt can fold the initializer, it will then mark the
   6 // variable as constant.
   7
   8 // Do not produce markers at -O0.
   9 // CHECK-O0-NOT: llvm.invariant.start.p0i8
  10
  11 struct A {
  12   A();
  13   int n;
  14 };
  15
  16 // CHECK: @a ={{.*}} global {{.*}} zeroinitializer
  17 extern const A a = A();
  18
  19 struct A2 {
  20   A2();
  21   constexpr ~A2() {}
  22   int n;
  23 };
  24
  25 // CHECK: @a2 ={{.*}} global {{.*}} zeroinitializer
  26 extern const A2 a2 = A2();
  27
  28
  29 struct B {
  30   B();
  31   mutable int n;
  32 };
  33
  34 // CHECK: @b ={{.*}} global {{.*}} zeroinitializer
  35 extern const B b = B();
  36
  37 struct C {
  38   C();
  39   ~C();
  40   int n;
  41 };
  42
  43 // CHECK: @c ={{.*}} global {{.*}} zeroinitializer
  44 extern const C c = C();
  45
  46 int f();
  47 // CHECK: @d ={{.*}} global i32 0
  48 extern const int d = f();
  49
  50 void e() {
  51   static const A a = A();
  52 }
  53
  54 // CHECK: call void @_ZN1AC1Ev(ptr noundef {{[^,]*}} @a)
  55 // CHECK: call {{.*}}@llvm.invariant.start.p0(i64 4, ptr @a)
  56
  57 // CHECK: call void @_ZN2A2C1Ev(ptr noundef {{[^,]*}} @a2)
  58 // CHECK: call {{.*}}@llvm.invariant.start.p0(i64 4, ptr @a2)
  59
  60 // CHECK: call void @_ZN1BC1Ev(ptr noundef {{[^,]*}} @b)
  61 // CHECK-NOT: call {{.*}}@llvm.invariant.start.p0(i64 noundef 4, ptr @b)
  62
  63 // CHECK: call void @_ZN1CC1Ev(ptr noundef {{[^,]*}} @c)
  64 // CHECK-NOT: call {{.*}}@llvm.invariant.start.p0(i64 noundef 4, ptr @c)
  65
  66 // CHECK: call noundef i32 @_Z1fv(
  67 // CHECK: store {{.*}}, ptr @d
  68 // CHECK: call {{.*}}@llvm.invariant.start.p0(i64 4, ptr @d)
  69
  70 // CHECK-LABEL: define{{.*}} void @_Z1ev(
  71 // CHECK: call void @_ZN1AC1Ev(ptr noundef {{[^,]*}} @_ZZ1evE1a)
  72 // CHECK: call {{.*}}@llvm.invariant.start.p0(i64 4, ptr {{.*}}@_ZZ1evE1a)
  73 // CHECK-NOT: llvm.invariant.end