================
@@ -0,0 +1,437 @@
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only
-fexperimental-new-constant-interpreter %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -triple
aarch64_be-linux-gnu -fexperimental-new-constant-interpreter %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only
-fexperimental-new-constant-interpreter -triple powerpc64le-unknown-unknown
-mabi=ieeelongdouble %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only
-fexperimental-new-constant-interpreter -triple powerpc64-unknown-unknown
-mabi=ieeelongdouble %s
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define LITTLE_END 1
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define LITTLE_END 0
+#else
+# error "huh?"
+#endif
+
+typedef decltype(nullptr) nullptr_t;
+typedef __INTPTR_TYPE__ intptr_t;
+typedef unsigned __INT16_TYPE__ uint16_t;
+typedef unsigned __INT32_TYPE__ uint32_t;
+typedef unsigned __INT64_TYPE__ uint64_t;
+
+static_assert(sizeof(int) == 4);
+static_assert(sizeof(long long) == 8);
+
+template <class To, class From>
+constexpr To bit_cast(const From &from) {
+ static_assert(sizeof(To) == sizeof(From));
+ return __builtin_bit_cast(To, from);
+}
+
+template <class Intermediate, class Init>
+constexpr bool check_round_trip(const Init &init) {
+ return bit_cast<Init>(bit_cast<Intermediate>(init)) == init;
+}
+
+template <class Intermediate, class Init>
+constexpr Init round_trip(const Init &init) {
+ return bit_cast<Init>(bit_cast<Intermediate>(init));
+}
+
+namespace std {
+enum byte : unsigned char {};
+} // namespace std
+
+template <int N, typename T = unsigned char, int Pad = 0>
+struct bits {
+ T : Pad;
+ T bits : N;
+
+ constexpr bool operator==(const T& rhs) const {
+ return bits == rhs;
+ }
+};
+
+template <int N, typename T, int P>
+constexpr bool operator==(const struct bits<N, T, P>& lhs, const struct
bits<N, T, P>& rhs) {
+ return lhs.bits == rhs.bits;
+}
+
+template<int N>
+struct bytes {
+ using size_t = unsigned int;
+ unsigned char d[N];
+
+ constexpr unsigned char operator[](size_t index) {
+ if (index < N)
+ return d[index];
+ return -1;
+ }
+};
+
+namespace Sanity {
+ /// This is just one byte, and we extract 2 bits from it.
+ ///
+ /// 3 is 0000'0011.
+ /// For both LE and BE, the buffer will contain exactly that
+ /// byte, unaltered and not reordered in any way. It contains all 8 bits.
+ static_assert(__builtin_bit_cast(bits<2>, (unsigned char)3) == (LITTLE_END ?
3 : 0));
+
+ /// Similarly, we have one full byte of data, with the two most-significant
+ /// bits set:
+ /// 192 is 1100'0000
+ static_assert(__builtin_bit_cast(bits<2>, (unsigned char)192) == (LITTLE_END
? 0 : 3));
+
+
+ /// Here we are instead bitcasting two 1-bits into a destination of 8 bits.
+ /// On LE, we should pick the two least-significant bits. On BE, the
opposite.
+ /// NOTE: Can't verify this with gcc.
+ constexpr auto B1 = bits<2>{3};
+ static_assert(__builtin_bit_cast(unsigned char, B1) == (LITTLE_END ? 3 :
192));
+
+ /// This should be 0000'0110.
+ /// On LE, this should result in 6.
+ /// On BE, 1100'0000 = 192.
+ constexpr auto B2 = bits<3>{6};
+ static_assert(__builtin_bit_cast(unsigned char, B2) == (LITTLE_END ? 6 :
192));
+
+ constexpr auto B3 = bits<4>{6};
+ static_assert(__builtin_bit_cast(unsigned char, B3) == (LITTLE_END ? 6 :
96));
+
+ struct B {
+ std::byte b0 : 4;
+ std::byte b1 : 4;
+ };
+
+ /// We can properly decompose one byte (8 bit) int two 4-bit bitfields.
+ constexpr struct { unsigned char b0; } T = {0xee};
+ constexpr B MB = __builtin_bit_cast(B, T);
+ static_assert(MB.b0 == 0xe);
+ static_assert(MB.b1 == 0xe);
+}
+
+namespace BitFields {
+ struct BitFields {
+ unsigned a : 2;
+ unsigned b : 30;
+ };
+
+ constexpr unsigned A = __builtin_bit_cast(unsigned, BitFields{3, 16});
+ static_assert(A == (LITTLE_END ? 67 : 3221225488));
+
+ struct S {
+ unsigned a : 2;
+ unsigned b : 28;
+ unsigned c : 2;
+ };
+
+ constexpr S s = __builtin_bit_cast(S, 0xFFFFFFFF);
+ static_assert(s.a == 3);
+ static_assert(s.b == 268435455);
+ static_assert(s.c == 3);
+
+ void bitfield_indeterminate() {
+ struct BF { unsigned char z : 2; };
+ enum byte : unsigned char {};
+
+ constexpr BF bf = {0x3};
+ /// Requires bitcasts to composite types.
+ static_assert(bit_cast<bits<2>>(bf).bits == bf.z);
+ static_assert(bit_cast<unsigned char>(bf));
+
+ static_assert(__builtin_bit_cast(byte, bf));
+
+ struct M {
+ // ref-note@+1 {{subobject declared here}}
+ unsigned char mem[sizeof(BF)];
+ };
+ // ref-error@+2 {{initialized by a constant expression}}
+ // ref-note@+1 {{not initialized}}
+ constexpr M m = bit_cast<M>(bf);
+
+ constexpr auto f = []() constexpr {
+ // bits<24, unsigned int, LITTLE_END ? 0 : 8> B = {0xc0ffee};
+ constexpr struct { unsigned short b1; unsigned char b0; } B = {0xc0ff,
0xee};
+ return bit_cast<bytes<4>>(B);
+ };
+
+ static_assert(f()[0] + f()[1] + f()[2] == 0xc0 + 0xff + 0xee);
+ {
+ // ref-error@+2 {{initialized by a constant expression}}
+ // ref-note@+1 {{read of uninitialized object is not allowed in a
constant expression}}
+ constexpr auto _bad = f()[3];
+ }
+
+ struct B {
+ unsigned short s0 : 8;
+ unsigned short s1 : 8;
+ std::byte b0 : 4;
+ std::byte b1 : 4;
+ std::byte b2 : 4;
+ };
+ constexpr auto g = [f]() constexpr {
+ return bit_cast<B>(f());
+ };
+ static_assert(g().s0 + g().s1 + g().b0 + g().b1 == 0xc0 + 0xff + 0xe +
0xe);
+ {
+ // ref-error@+2 {{initialized by a constant expression}}
+ // ref-note@+1 {{read of uninitialized object is not allowed in a
constant expression}}
+ constexpr auto _bad = g().b2;
+ }
+ }
+}
+
+namespace BoolVectors {
+ typedef bool bool32 __attribute__((ext_vector_type(32)));
+ constexpr auto v = bit_cast<bool32>(0xa1c0ffee);
+#if LITTLE_END
+ static_assert(!v[0]);
+ static_assert(v[1]);
+ static_assert(v[2]);
+ static_assert(v[3]);
+ static_assert(!v[4]);
+ static_assert(v[5]);
+ static_assert(v[6]);
+ static_assert(v[7]);
+
+ static_assert(v[8]);
+ static_assert(v[9]);
+ static_assert(v[10]);
+ static_assert(v[11]);
+ static_assert(v[12]);
+ static_assert(v[13]);
+ static_assert(v[14]);
+ static_assert(v[15]);
+
+ static_assert(!v[16]);
+ static_assert(!v[17]);
+ static_assert(!v[18]);
+ static_assert(!v[19]);
+ static_assert(!v[20]);
+ static_assert(!v[21]);
+ static_assert(v[22]);
+ static_assert(v[23]);
+
+ static_assert(v[24]);
+ static_assert(!v[25]);
+ static_assert(!v[26]);
+ static_assert(!v[27]);
+ static_assert(!v[28]);
+ static_assert(v[29]);
+ static_assert(!v[30]);
+ static_assert(v[31]);
+
+#else
+ static_assert(v[0]);
+ static_assert(!v[1]);
+ static_assert(v[2]);
+ static_assert(!v[3]);
+ static_assert(!v[4]);
+ static_assert(!v[5]);
+ static_assert(!v[6]);
+ static_assert(v[7]);
+
+ static_assert(v[8]);
+ static_assert(v[9]);
+ static_assert(!v[10]);
+ static_assert(!v[11]);
+ static_assert(!v[12]);
+ static_assert(!v[13]);
+ static_assert(!v[14]);
+ static_assert(!v[15]);
+
+ static_assert(v[16]);
+ static_assert(v[17]);
+ static_assert(v[18]);
+ static_assert(v[19]);
+ static_assert(v[20]);
+ static_assert(v[21]);
+ static_assert(v[22]);
+ static_assert(v[23]);
+
+ static_assert(v[24]);
+ static_assert(v[25]);
+ static_assert(v[26]);
+ static_assert(!v[27]);
+ static_assert(v[28]);
+ static_assert(v[29]);
+ static_assert(v[30]);
+ static_assert(!v[31]);
+#endif
+
+ struct pad {
+ unsigned short s;
+ unsigned char c;
+ };
+
+ constexpr auto p = bit_cast<pad>(v);
+ static_assert(p.s == (LITTLE_END ? 0xffee : 0xa1c0));
+ static_assert(p.c == (LITTLE_END ? 0xc0 : 0xff));
+}
+
+namespace TwoShorts {
+ struct B {
+ unsigned short s0 : 8;
+ unsigned short s1 : 8;
+ };
+ constexpr struct { unsigned short b1;} T = {0xc0ff};
+ constexpr B MB = __builtin_bit_cast(B, T);
+#if LITTLE_END
+ static_assert(MB.s0 == 0xff);
+ static_assert(MB.s1 == 0xc0);
+#else
+ static_assert(MB.s0 == 0xc0);
+ static_assert(MB.s1 == 0xff);
+
+#endif
+}
+
+typedef bool bool8 __attribute__((ext_vector_type(8)));
+typedef bool bool9 __attribute__((ext_vector_type(9)));
+typedef bool bool16 __attribute__((ext_vector_type(16)));
+typedef bool bool17 __attribute__((ext_vector_type(17)));
+typedef bool bool32 __attribute__((ext_vector_type(32)));
+typedef bool bool128 __attribute__((ext_vector_type(128)));
+
+static_assert(bit_cast<unsigned char>(bool8{1,0,1,0,1,0,1,0}) == (LITTLE_END ?
0x55 : 0xAA), "");
+constexpr bool8 b8 = __builtin_bit_cast(bool8, 0x55); // both-error
{{'__builtin_bit_cast' source type 'int' does not match destination type
'bool8' (vector of 8 'bool' values) (4 vs 1 bytes)}}
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0)), "");
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(1)), "");
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0x55)), "");
+
+static_assert(bit_cast<unsigned short>(bool16{1,1,1,1,1,0,0,0,
1,1,1,1,0,1,0,0}) == (LITTLE_END ? 0x2F1F : 0xF8F4), "");
+
+static_assert(check_round_trip<bool16>(static_cast<short>(0xCAFE)), "");
+static_assert(check_round_trip<bool32>(static_cast<int>(0xCAFEBABE)), "");
+static_assert(check_round_trip<bool128>(static_cast<__int128_t>(0xCAFEBABE0C05FEFEULL)),
"");
+
+static_assert(bit_cast<bits<8, uint16_t, 7>, uint16_t>(0xcafe) == (LITTLE_END
? 0x95 : 0x7f));
+static_assert(bit_cast<bits<4, uint16_t, 10>, uint16_t>(0xcafe) == (LITTLE_END
? 0x2 : 0xf));
+static_assert(bit_cast<bits<4, uint32_t, 19>, uint32_t>(0xa1cafe) ==
(LITTLE_END ? 0x4 : 0x5));
+
+struct S {
+ // little endian:
+ // MSB .... .... LSB
+ // |y| |x|
+ //
+ // big endian
+ // MSB .... .... LSB
+ // |x| |y|
+
+ unsigned char x : 4;
+ unsigned char y : 4;
+
+ constexpr bool operator==(S const &other) const {
+ return x == other.x && y == other.y;
+ }
+};
+
+constexpr S s{0xa, 0xb};
+static_assert(bit_cast<bits<8>>(s) == (LITTLE_END ? 0xba : 0xab));
+static_assert(bit_cast<bits<7>>(s) == (LITTLE_END
+ ? 0xba & 0x7f
+ : (0xab & 0xfe) >> 1));
+
+static_assert(round_trip<bits<8>>(s) == s);
+
+struct R {
+ unsigned int r : 31;
+ unsigned int : 0;
+ unsigned int : 32;
+ constexpr bool operator==(R const &other) const {
+ return r == other.r;
+ }
+ };
+using T = bits<31, signed long long>;
+constexpr R r{0x4ac0ffee};
+constexpr T t = bit_cast<T>(r);
+static_assert(t == ((0xFFFFFFFF8 << 28) | 0x4ac0ffee)); // sign extension
+
+static_assert(round_trip<T>(r) == r);
+static_assert(round_trip<R>(t) == t);
+
+
+/// The oversized bitfield is an error on Windows and not just a warning.
+#if !defined(_WIN32)
+struct U {
+ // expected-warning@+1 {{exceeds the width of its type}}
+ uint32_t trunc : 33;
+ uint32_t u : 31;
+ constexpr bool operator==(U const &other) const {
+ return trunc == other.trunc && u == other.u;
+ }
+};
+struct V {
+ uint64_t notrunc : 32;
+ uint64_t : 1;
+ uint64_t v : 31;
+ constexpr bool operator==(V const &other) const {
+ return notrunc == other.notrunc && v == other.v;
+ }
+};
+
+constexpr U u{static_cast<unsigned int>(~0), 0x4ac0ffee};
+constexpr V v = bit_cast<V>(u);
+static_assert(v.v == 0x4ac0ffee);
+
+static_assert(round_trip<V>(u) == u);
+static_assert(round_trip<U>(v) == v);
+
+constexpr auto w = bit_cast<bits<12, unsigned long, 33>>(u);
+static_assert(w == (LITTLE_END
+ ? 0x4ac0ffee & 0xFFF
+ : (0x4ac0ffee & (0xFFF << (31 - 12))) >> (31-12)
+ ));
+#endif
+
+
+namespace NestedStructures {
+ struct J {
+ struct {
+ uint16_t k : 12;
+ } K;
+ struct {
+ uint16_t l : 4;
+ } L;
+ };
+
+ static_assert(sizeof(J) == 4);
+ constexpr J j = bit_cast<J>(0x8c0ffee5);
+
+ static_assert(j.K.k == (LITTLE_END ? 0xee5 : 0x8c0));
+ static_assert(j.L.l == 0xf /* yay symmetry */);
+ static_assert(bit_cast<bits<4, uint16_t, 16>>(j) == 0xf);
+ struct N {
+ bits<12, uint16_t> k;
+ uint16_t : 16;
+ };
+ static_assert(bit_cast<N>(j).k == j.K.k);
+
+ struct M {
+ bits<4, uint16_t, 0> m[2];
+ constexpr bool operator==(const M& rhs) const {
+ return m[0] == rhs.m[0] && m[1] == rhs.m[1];
+ };
+ };
+ #if LITTLE_END == 1
+ constexpr uint16_t want[2] = {0x5, 0xf};
+ #else
+ constexpr uint16_t want[2] = {0x8000, 0xf000};
+ #endif
+
+ static_assert(bit_cast<M>(j) == bit_cast<M>(want));
+}
+
+namespace Enums {
+ // ensure we're packed into the top 2 bits
+ constexpr int pad = LITTLE_END ? 6 : 0;
+ struct X
+ {
+ char : pad;
+ enum class direction: char { left, right, up, down } direction : 2;
+ };
+
+ constexpr X x = { X::direction::down };
+ static_assert(bit_cast<bits<2, signed char, pad>>(x) == -1);
+ static_assert(bit_cast<bits<2, unsigned char, pad>>(x) == 3);
+ static_assert(
+ bit_cast<X>((unsigned char)0x40).direction == X::direction::right);
+}
----------------
AaronBallman wrote:
Some more test coverage you might want to consider adding:
* Structs with zero-sized fields, like `struct S {}; struct T { S s; };`
* Structs where the zero-sized field is `[[no_unique_address]]` merged with
other fields.
* Structs with a flexible array member
*
https://github.com/llvm/llvm-project/pull/116843
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