226 lines
8.1 KiB
C++
226 lines
8.1 KiB
C++
// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm %s -std=c++2a -o %t.ll
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// RUN: FileCheck -check-prefix=CHECK-FN-CG -input-file=%t.ll %s
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// RUN: FileCheck -check-prefix=CHECK-STATIC -input-file=%t.ll %s
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// RUN: FileCheck -check-prefix=CHECK-DYN -input-file=%t.ll %s
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// RUN: FileCheck -check-prefix=CHECK-ARR -input-file=%t.ll %s
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// RUN: FileCheck -check-prefix=CHECK-FOLD -input-file=%t.ll %s
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// RUN: FileCheck -check-prefix=CHECK-DTOR -input-file=%t.ll %s
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using size_t = decltype(sizeof(int));
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#define CONSTINIT __attribute__((require_constant_initialization))
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extern "C" [[noreturn]] void BOOM();
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extern "C" void OK();
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extern "C" size_t RANDU();
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namespace std {
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inline constexpr bool is_constant_evaluated() noexcept {
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return __builtin_is_constant_evaluated();
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}
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} // namespace std
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// CHECK-FN-CG-LABEL: define{{.*}} zeroext i1 @_Z3foov()
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// CHECK-FN-CG: ret i1 false
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bool foo() {
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return __builtin_is_constant_evaluated();
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}
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// CHECK-FN-CG-LABEL: define linkonce_odr noundef i32 @_Z1fv()
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constexpr int f() {
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// CHECK-FN-CG: store i32 13, i32* %n, align 4
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// CHECK-FN-CG: store i32 17, i32* %m, align 4
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// CHECK-FN-CG: %1 = load i32, i32* %m, align 4
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// CHECK-FN-CG: %add = add nsw i32 %1, 13
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// CHECK-FN-CG: ret i32 %add
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const int n = __builtin_is_constant_evaluated() && std::is_constant_evaluated() ? 13 : 17; // n == 13
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int m = __builtin_is_constant_evaluated() ? 13 : 17; // m might be 13 or 17 (see below)
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char arr[n] = {}; // char[13]
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return m + int(sizeof(arr));
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}
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// CHECK-STATIC-DAG: @p ={{.*}} global i32 26,
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CONSTINIT int p = f(); // f().m == 13; initialized to 26
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// CHECK-STATIC-DAG: @p2 ={{.*}} global i32 26,
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int p2 = f(); // same result without CONSTINIT
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// CHECK-DYN-LABEL: define internal void @__cxx_global_var_init()
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// CHECK-DYN: %0 = load i32, i32* @p, align 4
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// CHECK-DYN-NEXT: %call = call noundef i32 @_Z1fv()
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// CHECK-DYN-NEXT: %add = add nsw i32 %0, %call
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// CHECK-DYN-NEXT: store i32 %add, i32* @q, align 4
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// CHECK-DYN-NEXT: ret void
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int q = p + f(); // m == 17 for this call; initialized to 56
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int y;
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// CHECK-STATIC-DAG: @b ={{.*}} global i32 2,
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CONSTINIT int b = __builtin_is_constant_evaluated() ? 2 : y; // static initialization to 2
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// CHECK-DYN-LABEL: define internal void @__cxx_global_var_init.1()
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// CHECK-DYN: %0 = load i32, i32* @y, align 4
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// CHECK-DYN: %1 = load i32, i32* @y, align 4
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// CHECK-DYN-NEXT: %add = add
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// CHECK-DYN-NEXT: store i32 %add, i32* @c,
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int c = y + (__builtin_is_constant_evaluated() ? 2 : y); // dynamic initialization to y+y
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// This is dynamic initialization that we can convert to static initialization
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// during lowering. When doing so, the dynamic initializer value is preserved.
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// CHECK-STATIC-DAG: @_ZL1a = internal constant i32 1
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const int a = __builtin_is_constant_evaluated() ? y : 1; // dynamic initialization to 1
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const int *a_sink = &a;
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// CHECK-ARR-LABEL: define{{.*}} void @_Z13test_arr_exprv
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void test_arr_expr() {
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// CHECK-ARR: %x1 = alloca [101 x i8],
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char x1[std::is_constant_evaluated() && __builtin_is_constant_evaluated() ? 101 : 1];
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// CHECK-ARR: %x2 = alloca [42 x i8],
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char x2[std::is_constant_evaluated() && __builtin_is_constant_evaluated() ? 42 : RANDU()];
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// CHECK-ARR: call i8* @llvm.stacksave()
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// CHECK-ARR: %vla = alloca i8, i64 13,
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char x3[std::is_constant_evaluated() || __builtin_is_constant_evaluated() ? RANDU() : 13];
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}
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// CHECK-ARR-LABEL: define{{.*}} void @_Z17test_new_arr_exprv
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void test_new_arr_expr() {
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// CHECK-ARR: call noalias noundef nonnull i8* @_Znam(i64 noundef 17)
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new char[std::is_constant_evaluated() || __builtin_is_constant_evaluated() ? 1 : 17];
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}
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// CHECK-FOLD-LABEL: @_Z31test_constant_initialized_locali(
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bool test_constant_initialized_local(int k) {
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// CHECK-FOLD: store i8 1, i8* %n,
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// CHECK-FOLD: store volatile i8* %n, i8** %p,
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const bool n = __builtin_is_constant_evaluated() && std::is_constant_evaluated();
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const bool *volatile p = &n;
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return *p;
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}
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// CHECK-FOLD-LABEL: define{{.*}} void @_Z21test_ir_constant_foldv()
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void test_ir_constant_fold() {
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// CHECK-FOLD-NEXT: entry:
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// CHECK-FOLD-NEXT: call void @OK()
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// CHECK-FOLD-NEXT: call void @OK()
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// CHECK-FOLD-NEXT: ret void
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if (std::is_constant_evaluated()) {
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BOOM();
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} else {
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OK();
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}
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std::is_constant_evaluated() ? BOOM() : OK();
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}
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// CHECK-STATIC-DAG: @ir ={{.*}} constant i32* @i_constant,
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int i_constant;
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int i_not_constant;
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int &ir = __builtin_is_constant_evaluated() ? i_constant : i_not_constant;
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// CHECK-FOLD-LABEL: @_Z35test_ref_initialization_local_scopev()
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void test_ref_initialization_local_scope() {
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const int i_constant = 42;
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const int i_non_constant = 101;
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// CHECK-FOLD: store i32* %i_non_constant, i32** %r,
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const int &r = __builtin_is_constant_evaluated() ? i_constant : i_non_constant;
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}
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// CHECK-FOLD-LABEL: @_Z22test_ref_to_static_varv()
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void test_ref_to_static_var() {
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static int i_constant = 42;
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static int i_non_constant = 101;
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// CHECK-FOLD: store i32* @_ZZ22test_ref_to_static_varvE10i_constant, i32** %r,
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int &r = __builtin_is_constant_evaluated() ? i_constant : i_non_constant;
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}
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int not_constexpr;
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// __builtin_is_constant_evaluated() should never evaluate to true during
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// destruction if it would not have done so during construction.
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//
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// FIXME: The standard doesn't say that it should ever return true when
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// evaluating a destructor call, even for a constexpr variable. That seems
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// obviously wrong.
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struct DestructorBCE {
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int n;
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constexpr DestructorBCE(int n) : n(n) {}
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constexpr ~DestructorBCE() {
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if (!__builtin_is_constant_evaluated())
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not_constexpr = 1;
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}
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};
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// CHECK-DTOR-NOT: @_ZN13DestructorBCED{{.*}}@global_dtor_bce_1
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DestructorBCE global_dtor_bce_1(101);
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// CHECK-DTOR: load i32, i32* @not_constexpr
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCEC1Ei({{.*}} @global_dtor_bce_2, i32
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// CHECK-DTOR: atexit{{.*}} @_ZN13DestructorBCED{{.*}} @global_dtor_bce_2
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// CHECK-DTOR: }
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DestructorBCE global_dtor_bce_2(not_constexpr);
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// CHECK-DTOR-NOT: @_ZN13DestructorBCED{{.*}}@global_dtor_bce_3
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constexpr DestructorBCE global_dtor_bce_3(103);
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// CHECK-DTOR-LABEL: define {{.*}} @_Z15test_dtor_bce_1v(
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void test_dtor_bce_1() {
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// Variable is neither constant initialized (because it has automatic storage
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// duration) nor usable in constant expressions, so BCE should not return
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// true during destruction. It would be OK if we replaced the constructor
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// call with a direct store, but we should emit the destructor call.
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCEC1Ei({{.*}}, i32 noundef 201)
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DestructorBCE local(201);
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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// CHECK-DTOR-LABEL: define {{.*}} @_Z15test_dtor_bce_2v(
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void test_dtor_bce_2() {
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// Non-constant init => BCE is false in destructor.
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCEC1Ei({{.*}}
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DestructorBCE local(not_constexpr);
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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// CHECK-DTOR-LABEL: define {{.*}} @_Z15test_dtor_bce_3v(
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void test_dtor_bce_3() {
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// Should never call dtor for a constexpr variable.
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// CHECK-DTOR-NOT: call {{.*}} @_ZN13DestructorBCEC1Ei(
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constexpr DestructorBCE local(203);
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// CHECK-DTOR-NOT: @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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// CHECK-DTOR-LABEL: define {{.*}} @_Z22test_dtor_bce_static_1v(
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void test_dtor_bce_static_1() {
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// Variable is constant initialized, so BCE returns true during constant
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// destruction.
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// CHECK: store i32 301
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// CHECK-DTOR-NOT: @_ZN13DestructorBCEC1Ei({{.*}}
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static DestructorBCE local(301);
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// CHECK-DTOR-NOT: @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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// CHECK-DTOR-LABEL: define {{.*}} @_Z22test_dtor_bce_static_2v(
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void test_dtor_bce_static_2() {
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// CHECK-DTOR: call {{.*}} @_ZN13DestructorBCEC1Ei({{.*}}
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static DestructorBCE local(not_constexpr);
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// CHECK-DTOR: call {{.*}}atexit{{.*}} @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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// CHECK-DTOR-LABEL: define {{.*}} @_Z22test_dtor_bce_static_3v(
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void test_dtor_bce_static_3() {
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// CHECK: store i32 303
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// CHECK-DTOR-NOT: @_ZN13DestructorBCEC1Ei({{.*}}
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static constexpr DestructorBCE local(303);
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// CHECK-DTOR-NOT: @_ZN13DestructorBCED
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// CHECK-DTOR: }
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}
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