Commit a024aff9324e827d6595e44f922d87f8ed2dbd0d | zig

author	Andrew Kelley <andrew@ziglang.org> 2022-02-10 22:06:43-07:00
committer	Jakub Konka <kubkon@jakubkonka.com> 2022-02-12 11:18:23+01:00
log	a024aff9324e827d6595e44f922d87f8ed2dbd0d
tree	2c0557a4e57acd198ca57deb7cc387109d96c26d
parent	1c23321d03a48558b02c2faf818b82811b8ab11d

make f80 less hacky; lower as u80 on non-x86

Get rid of `std.math.F80Repr`. Instead of trying to match the memory
layout of f80, we treat it as a value, same as the other floating point
types. The functions `make_f80` and `break_f80` are introduced to
compose an f80 value out of its parts, and the inverse operation.

stage2 LLVM backend: fix pointer to zero length array tripping LLVM
assertion. It now checks for when the element type is a zero-bit type
and lowers such thing the same way that pointers to other zero-bit types
are lowered.

Both stage1 and stage2 LLVM backends are adjusted so that f80 is lowered
as x86_fp80 on x86_64 and i386 architectures, and identical to a u80 on
others. LLVM constants are lowered in a less hacky way now that #10860
is fixed, by using the expression `(exp << 64) | fraction` using llvm
constants.

Sema is improved to handle c_longdouble by recursively handling it
correctly for whatever the float bit width is. In both stage1 and
stage2.

10 files changed, 201 insertions(+), 111 deletions(-)

lib
- std
  - math.zig
  - special
    compiler_rt
    addXf3.zig
    compareXf2.zig
    extend_f80.zig
    trunc_f80.zig
src
- codegen
  - llvm.zig
- stage1
  - codegen.cpp
- type.zig
- value.zig
test
- behavior
  - floatop.zig

lib/std/math.zig+25-15

...	...	@@ -42,19 +42,11 @@ pub const f128_max = @bitCast(f128, @as(u128, 0x7FFEFFFFFFFFFFFFFFFFFFFFFFFFFFFF
42	42	pub const f128_epsilon = @bitCast(f128, @as(u128, 0x3F8F0000000000000000000000000000));
43	43	pub const f128_toint = 1.0 / f128_epsilon;
44	44
45		pub const F80Repr = if (@import("builtin").cpu.arch.endian() == .Little) extern struct {
46		fraction: u64 align(@alignOf(f80)),
47		exp: u16,
48		} else extern struct {
49		exp: u16 align(@alignOf(f80)),
50		fraction: u64,
51		};
52
53	45	// float.h details
54		pub const f80_true_min = @ptrCast(const f80, &F80Repr{ .fraction = 1, .exp = 0 }).;
55		pub const f80_min = @ptrCast(const f80, &F80Repr{ .fraction = 0x8000000000000000, .exp = 1 }).;
56		pub const f80_max = @ptrCast(const f80, &F80Repr{ .fraction = 0xFFFFFFFFFFFFFFFF, .exp = 0x7FFE }).;
57		pub const f80_epsilon = @ptrCast(const f80, &F80Repr{ .fraction = 0x8000000000000000, .exp = 0x3FC0 }).;
	46	pub const f80_true_min = make_f80(.{ .fraction = 1, .exp = 0 });
	47	pub const f80_min = make_f80(.{ .fraction = 0x8000000000000000, .exp = 1 });
	48	pub const f80_max = make_f80(.{ .fraction = 0xFFFFFFFFFFFFFFFF, .exp = 0x7FFE });
	49	pub const f80_epsilon = make_f80(.{ .fraction = 0x8000000000000000, .exp = 0x3FC0 });
58	50	pub const f80_toint = 1.0 / f80_epsilon;
59	51
60	52	pub const f64_true_min = 4.94065645841246544177e-324;
...	...	@@ -104,9 +96,9 @@ pub const qnan_f64 = @bitCast(f64, qnan_u64);
104	96	pub const inf_u64 = @as(u64, 0x7FF << 52);
105	97	pub const inf_f64 = @bitCast(f64, inf_u64);
106	98
107		pub const inf_f80 = @ptrCast(const f80, &F80Repr{ .fraction = 0x8000000000000000, .exp = 0x7fff }).;
108		pub const nan_f80 = @ptrCast(const f80, &F80Repr{ .fraction = 0xA000000000000000, .exp = 0x7fff }).;
109		pub const qnan_f80 = @ptrCast(const f80, &F80Repr{ .fraction = 0xC000000000000000, .exp = 0x7fff }).;
	99	pub const inf_f80 = make_f80(F80{ .fraction = 0x8000000000000000, .exp = 0x7fff });
	100	pub const nan_f80 = make_f80(F80{ .fraction = 0xA000000000000000, .exp = 0x7fff });
	101	pub const qnan_f80 = make_f80(F80{ .fraction = 0xC000000000000000, .exp = 0x7fff });
110	102
111	103	pub const nan_u128 = @as(u128, 0x7fff0000000000000000000000000001);
112	104	pub const nan_f128 = @bitCast(f128, nan_u128);
...	...	@@ -1501,3 +1493,21 @@ test "boolMask" {
1501	1493	pub fn comptimeMod(num: anytype, denom: comptime_int) IntFittingRange(0, denom - 1) {
1502	1494	return @intCast(IntFittingRange(0, denom - 1), @mod(num, denom));
1503	1495	}
	1496
	1497	pub const F80 = struct {
	1498	fraction: u64,
	1499	exp: u16,
	1500	};
	1501
	1502	pub fn make_f80(repr: F80) f80 {
	1503	const int = (@as(u80, repr.exp) << 64) \| repr.fraction;
	1504	return @bitCast(f80, int);
	1505	}
	1506
	1507	pub fn break_f80(x: f80) F80 {
	1508	const int = @bitCast(u80, x);
	1509	return .{
	1510	.fraction = @truncate(u64, int),
	1511	.exp = @truncate(u16, int >> 64),
	1512	};
	1513	}

lib/std/special/compiler_rt/addXf3.zig+9-9

...	...	@@ -232,8 +232,8 @@ fn normalize_f80(exp: i32, significand: u80) void {
232	232	}
233	233
234	234	pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
235		var a_rep align(16) = @ptrCast(const std.math.F80Repr, &a).;
236		var b_rep align(16) = @ptrCast(const std.math.F80Repr, &b).;
	235	var a_rep = std.math.break_f80(a);
	236	var b_rep = std.math.break_f80(b);
237	237	var a_exp: i32 = a_rep.exp & 0x7FFF;
238	238	var b_exp: i32 = b_rep.exp & 0x7FFF;
239	239
...	...	@@ -257,7 +257,7 @@ pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
257	257	std.debug.assert(a_rep.fraction & significand_mask != 0);
258	258	// NaN + anything = qNaN
259	259	a_rep.fraction \|= qnan_bit;
260		return @ptrCast(const f80, &a_rep).;
	260	return std.math.make_f80(a_rep);
261	261	}
262	262	}
263	263	if (b_exp == max_exp) {
...	...	@@ -268,7 +268,7 @@ pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
268	268	std.debug.assert(b_rep.fraction & significand_mask != 0);
269	269	// anything + NaN = qNaN
270	270	b_rep.fraction \|= qnan_bit;
271		return @ptrCast(const f80, &b_rep).;
	271	return std.math.make_f80(b_rep);
272	272	}
273	273	}
274	274
...	...	@@ -279,7 +279,7 @@ pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
279	279	if (b_zero) {
280	280	// but we need to get the sign right for zero + zero
281	281	a_rep.exp &= b_rep.exp;
282		return @ptrCast(const f80, &a_rep).;
	282	return std.math.make_f80(a_rep);
283	283	} else {
284	284	return b;
285	285	}
...	...	@@ -359,7 +359,7 @@ pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
359	359	if (a_exp >= max_exp) {
360	360	a_rep.exp = max_exp \| result_sign;
361	361	a_rep.fraction = int_bit; // integer bit is set for +/-inf
362		return @ptrCast(const f80, &a_rep).;
	362	return std.math.make_f80(a_rep);
363	363	}
364	364
365	365	if (a_exp <= 0) {
...	...	@@ -387,13 +387,13 @@ pub fn __addxf3(a: f80, b: f80) callconv(.C) f80 {
387	387
388	388	a_rep.fraction = @truncate(u64, a_int);
389	389	a_rep.exp = @truncate(u16, a_int >> significand_bits);
390		return @ptrCast(const f80, &a_rep).;
	390	return std.math.make_f80(a_rep);
391	391	}
392	392
393	393	pub fn __subxf3(a: f80, b: f80) callconv(.C) f80 {
394		var b_rep align(16) = @ptrCast(const std.math.F80Repr, &b).;
	394	var b_rep = std.math.break_f80(b);
395	395	b_rep.exp ^= 0x8000;
396		return __addxf3(a, @ptrCast(const f80, &b_rep).);
	396	return __addxf3(a, std.math.make_f80(b_rep));
397	397	}
398	398
399	399	test {

lib/std/special/compiler_rt/compareXf2.zig+2-2

...	...	@@ -147,8 +147,8 @@ pub fn __gtdf2(a: f64, b: f64) callconv(.C) i32 {
147	147	// Comparison between f80
148	148
149	149	pub inline fn cmp_f80(comptime RT: type, a: f80, b: f80) RT {
150		const a_rep = @ptrCast(const std.math.F80Repr, &a).;
151		const b_rep = @ptrCast(const std.math.F80Repr, &b).;
	150	const a_rep = std.math.break_f80(a);
	151	const b_rep = std.math.break_f80(b);
152	152	const sig_bits = std.math.floatMantissaBits(f80);
153	153	const int_bit = 0x8000000000000000;
154	154	const sign_bit = 0x8000;

lib/std/special/compiler_rt/extend_f80.zig+3-3

...	...	@@ -41,7 +41,7 @@ inline fn extendF80(comptime src_t: type, a: std.meta.Int(.unsigned, @typeInfo(s
41	41	const src_qnan = 1 << (src_sig_bits - 1);
42	42	const src_nan_code = src_qnan - 1;
43	43
44		var dst: std.math.F80Repr align(16) = undefined;
	44	var dst: std.math.F80 = undefined;
45	45
46	46	// Break a into a sign and representation of the absolute value
47	47	const a_abs = a & src_abs_mask;
...	...	@@ -83,7 +83,7 @@ inline fn extendF80(comptime src_t: type, a: std.meta.Int(.unsigned, @typeInfo(s
83	83	}
84	84
85	85	dst.exp \|= sign;
86		return @ptrCast(const f80, &dst).;
	86	return std.math.make_f80(dst);
87	87	}
88	88
89	89	pub fn __extendxftf2(a: f80) callconv(.C) f128 {
...	...	@@ -99,7 +99,7 @@ pub fn __extendxftf2(a: f80) callconv(.C) f128 {
99	99	const dst_min_normal = @as(u128, 1) << dst_sig_bits;
100	100
101	101	// Break a into a sign and representation of the absolute value
102		var a_rep = @ptrCast(const std.math.F80Repr, &a).;
	102	var a_rep = std.math.break_f80(a);
103	103	const sign = a_rep.exp & 0x8000;
104	104	a_rep.exp &= 0x7FFF;
105	105	var abs_result: u128 = undefined;

lib/std/special/compiler_rt/trunc_f80.zig+3-3

...	...	@@ -42,7 +42,7 @@ inline fn trunc(comptime dst_t: type, a: f80) dst_t {
42	42	const dst_nan_mask = dst_qnan - 1;
43	43
44	44	// Break a into a sign and representation of the absolute value
45		var a_rep = @ptrCast(const std.math.F80Repr, &a).;
	45	var a_rep = std.math.break_f80(a);
46	46	const sign = a_rep.exp & 0x8000;
47	47	a_rep.exp &= 0x7FFF;
48	48	a_rep.fraction &= 0x7FFFFFFFFFFFFFFF;
...	...	@@ -125,7 +125,7 @@ pub fn __trunctfxf2(a: f128) callconv(.C) f80 {
125	125	const a_abs = a_rep & src_abs_mask;
126	126	const sign: u16 = if (a_rep & src_sign_mask != 0) 0x8000 else 0;
127	127
128		var res: std.math.F80Repr align(16) = undefined;
	128	var res: std.math.F80 = undefined;
129	129
130	130	if (a_abs > src_inf) {
131	131	// a is NaN.
...	...	@@ -155,5 +155,5 @@ pub fn __trunctfxf2(a: f128) callconv(.C) f80 {
155	155	}
156	156
157	157	res.exp \|= sign;
158		return @ptrCast(const f80, &res).;
	158	return std.math.make_f80(res);
159	159	}

src/codegen/llvm.zig+28-13

...	...	@@ -824,23 +824,24 @@ pub const DeclGen = struct {
824	824
825	825	fn llvmType(dg: DeclGen, t: Type) Allocator.Error!const llvm.Type {
826	826	const gpa = dg.gpa;
	827	const target = dg.module.getTarget();
827	828	switch (t.zigTypeTag()) {
828	829	.Void, .NoReturn => return dg.context.voidType(),
829	830	.Int => {
830		const info = t.intInfo(dg.module.getTarget());
	831	const info = t.intInfo(target);
831	832	return dg.context.intType(info.bits);
832	833	},
833	834	.Enum => {
834	835	var buffer: Type.Payload.Bits = undefined;
835	836	const int_ty = t.intTagType(&buffer);
836		const bit_count = int_ty.intInfo(dg.module.getTarget()).bits;
	837	const bit_count = int_ty.intInfo(target).bits;
837	838	return dg.context.intType(bit_count);
838	839	},
839		.Float => switch (t.floatBits(dg.module.getTarget())) {
	840	.Float => switch (t.floatBits(target)) {
840	841	16 => return dg.context.halfType(),
841	842	32 => return dg.context.floatType(),
842	843	64 => return dg.context.doubleType(),
843		80 => return dg.context.x86FP80Type(),
	844	80 => return if (backendSupportsF80(target)) dg.context.x86FP80Type() else dg.context.intType(80),
844	845	128 => return dg.context.fp128Type(),
845	846	else => unreachable,
846	847	},
...	...	@@ -859,7 +860,8 @@ pub const DeclGen = struct {
859	860	const llvm_addrspace = dg.llvmAddressSpace(t.ptrAddressSpace());
860	861	const elem_ty = t.childType();
861	862	const lower_elem_ty = switch (elem_ty.zigTypeTag()) {
862		.Opaque, .Array, .Fn => true,
	863	.Opaque, .Fn => true,
	864	.Array => elem_ty.childType().hasRuntimeBits(),
863	865	else => elem_ty.hasRuntimeBits(),
864	866	};
865	867	const llvm_elem_ty = if (lower_elem_ty)
...	...	@@ -889,9 +891,11 @@ pub const DeclGen = struct {
889	891	else => unreachable,
890	892	},
891	893	.Array => {
892		const elem_type = try dg.llvmType(t.childType());
	894	const elem_ty = t.childType();
	895	assert(elem_ty.onePossibleValue() == null);
	896	const elem_llvm_ty = try dg.llvmType(elem_ty);
893	897	const total_len = t.arrayLen() + @boolToInt(t.sentinel() != null);
894		return elem_type.arrayType(@intCast(c_uint, total_len));
	898	return elem_llvm_ty.arrayType(@intCast(c_uint, total_len));
895	899	},
896	900	.Vector => {
897	901	const elem_type = try dg.llvmType(t.childType());
...	...	@@ -978,7 +982,6 @@ pub const DeclGen = struct {
978	982
979	983	if (struct_obj.layout == .Packed) {
980	984	try llvm_field_types.ensureUnusedCapacity(gpa, struct_obj.fields.count() * 2);
981		const target = dg.module.getTarget();
982	985	comptime assert(Type.packed_struct_layout_version == 1);
983	986	var offset: u64 = 0;
984	987	var big_align: u32 = 0;
...	...	@@ -1073,7 +1076,6 @@ pub const DeclGen = struct {
1073	1076	gop.key_ptr.* = try t.copy(dg.object.type_map_arena.allocator());
1074	1077
1075	1078	const union_obj = t.cast(Type.Payload.Union).?.data;
1076		const target = dg.module.getTarget();
1077	1079	if (t.unionTagType()) \|enum_tag_ty\| {
1078	1080	const enum_tag_llvm_ty = try dg.llvmType(enum_tag_ty);
1079	1081	const layout = union_obj.getLayout(target, true);
...	...	@@ -1141,7 +1143,6 @@ pub const DeclGen = struct {
1141	1143	},
1142	1144	.Fn => {
1143	1145	const fn_info = t.fnInfo();
1144		const target = dg.module.getTarget();
1145	1146	const sret = firstParamSRet(fn_info, target);
1146	1147	const return_type = fn_info.return_type;
1147	1148	const raw_llvm_ret_ty = try dg.llvmType(return_type);
...	...	@@ -1257,16 +1258,21 @@ pub const DeclGen = struct {
1257	1258	},
1258	1259	.Float => {
1259	1260	const llvm_ty = try dg.llvmType(tv.ty);
1260		switch (tv.ty.floatBits(dg.module.getTarget())) {
	1261	const target = dg.module.getTarget();
	1262	switch (tv.ty.floatBits(target)) {
1261	1263	16, 32, 64 => return llvm_ty.constReal(tv.val.toFloat(f64)),
1262	1264	80 => {
1263	1265	const float = tv.val.toFloat(f80);
1264		const repr = @ptrCast(*const std.math.F80Repr, &float);
	1266	const repr = std.math.break_f80(float);
1265	1267	const llvm_i80 = dg.context.intType(80);
1266	1268	var x = llvm_i80.constInt(repr.exp, .False);
1267	1269	x = x.constShl(llvm_i80.constInt(64, .False));
1268	1270	x = x.constOr(llvm_i80.constInt(repr.fraction, .False));
1269		return x.constBitCast(llvm_ty);
	1271	if (backendSupportsF80(target)) {
	1272	return x.constBitCast(llvm_ty);
	1273	} else {
	1274	return x;
	1275	}
1270	1276	},
1271	1277	128 => {
1272	1278	var buf: [2]u64 = @bitCast([2]u64, tv.val.toFloat(f128));
...	...	@@ -5353,3 +5359,12 @@ fn isByRef(ty: Type) bool {
5353	5359	},
5354	5360	}
5355	5361	}
	5362
	5363	/// This function returns true if we expect LLVM to lower x86_fp80 correctly
	5364	/// and false if we expect LLVM to crash if it counters an x86_fp80 type.
	5365	fn backendSupportsF80(target: std.Target) bool {
	5366	return switch (target.cpu.arch) {
	5367	.x86_64, .i386 => true,
	5368	else => false,
	5369	};
	5370	}

src/stage1/codegen.cpp+36-34

...	...	@@ -8195,17 +8195,15 @@ static LLVMValueRef gen_const_val(CodeGen g, ZigValue const_val, const char *n
8195	8195	case 64:
8196	8196	return LLVMConstReal(get_llvm_type(g, type_entry), const_val->data.x_f64);
8197	8197	case 80: {
8198		uint64_t buf[2];
8199		memcpy(&buf, &const_val->data.x_f80, 16);
8200		#if ZIG_BYTE_ORDER == ZIG_BIG_ENDIAN
8201		uint64_t tmp = buf[0];
8202		buf[0] = buf[1];
8203		buf[1] = tmp;
8204		#endif
8205		LLVMValueRef as_i128 = LLVMConstIntOfArbitraryPrecision(LLVMInt128Type(), 2, buf);
8206		if (!target_has_f80(g->zig_target)) return as_i128;
8207		LLVMValueRef as_int = LLVMConstTrunc(as_i128, LLVMIntType(80));
8208		return LLVMConstBitCast(as_int, get_llvm_type(g, type_entry));
	8198	LLVMTypeRef llvm_i80 = LLVMIntType(80);
	8199	LLVMValueRef x = LLVMConstInt(llvm_i80, const_val->data.x_f80.signExp, false);
	8200	x = LLVMConstShl(x, LLVMConstInt(llvm_i80, 64, false));
	8201	x = LLVMConstOr(x, LLVMConstInt(llvm_i80, const_val->data.x_f80.signif, false));
	8202	if (target_has_f80(g->zig_target)) {
	8203	return LLVMConstBitCast(x, LLVMX86FP80Type());
	8204	} else {
	8205	return x;
	8206	}
8209	8207	}
8210	8208	case 128:
8211	8209	{
...	...	@@ -9429,32 +9427,36 @@ static void define_builtin_types(CodeGen *g) {
9429	9427
9430	9428	{
9431	9429	ZigType *entry = new_type_table_entry(ZigTypeIdFloat);
9432		unsigned u64_alignment = LLVMABIAlignmentOfType(g->target_data_ref, LLVMInt64Type());
9433
9434		if (u64_alignment >= 8) {
9435		entry->size_in_bits = 128;
9436		entry->abi_size = 16;
9437		entry->abi_align = 16;
9438		} else if (u64_alignment >= 4) {
9439		entry->size_in_bits = 96;
9440		entry->abi_size = 12;
9441		entry->abi_align = 4;
9442		} else {
9443		entry->size_in_bits = 80;
9444		entry->abi_size = 10;
9445		entry->abi_align = 2;
9446		}
9447		if (target_has_f80(g->zig_target)) {
9448		entry->llvm_type = LLVMX86FP80Type();
9449		} else {
9450		// We use an int here instead of x86_fp80 because on targets such as arm,
9451		// LLVM will give "ERROR: Cannot select" for any instructions involving
9452		// the x86_fp80 type.
9453		entry->llvm_type = get_int_type(g, false, entry->size_in_bits)->llvm_type;
9454		}
	9430	entry->size_in_bits = 80;
	9431
9455	9432	buf_init_from_str(&entry->name, "f80");
9456	9433	entry->data.floating.bit_count = 80;
9457	9434
	9435	switch (g->zig_target->arch) {
	9436	case ZigLLVM_x86_64:
	9437	entry->llvm_type = LLVMX86FP80Type();
	9438	entry->abi_size = 16;
	9439	entry->abi_align = 16;
	9440	break;
	9441	case ZigLLVM_x86:
	9442	entry->llvm_type = LLVMX86FP80Type();
	9443	entry->abi_size = 12;
	9444	entry->abi_align = 4;
	9445	break;
	9446	default: {
	9447	// We use an int here instead of x86_fp80 because on targets such as arm,
	9448	// LLVM will give "ERROR: Cannot select" for any instructions involving
	9449	// the x86_fp80 type.
	9450	ZigType *u80_ty = get_int_type(g, false, 80);
	9451	assert(!target_has_f80(g->zig_target));
	9452	assert(u80_ty->size_in_bits == entry->size_in_bits);
	9453	entry->llvm_type = get_llvm_type(g, u80_ty);
	9454	entry->abi_size = u80_ty->abi_size;
	9455	entry->abi_align = u80_ty->abi_align;
	9456	break;
	9457	}
	9458	}
	9459
9458	9460	entry->llvm_di_type = ZigLLVMCreateDebugBasicType(g->dbuilder, buf_ptr(&entry->name),
9459	9461	entry->size_in_bits, ZigLLVMEncoding_DW_ATE_unsigned());
9460	9462

src/type.zig+50-5

...	...	@@ -1877,9 +1877,28 @@ pub const Type = extern union {
1877	1877	.f16 => return 2,
1878	1878	.f32 => return 4,
1879	1879	.f64 => return 8,
1880		.f80 => return 16,
1881	1880	.f128 => return 16,
1882		.c_longdouble => return 16,
	1881
	1882	.f80 => switch (target.cpu.arch) {
	1883	.i386 => return 4,
	1884	.x86_64 => return 16,
	1885	else => {
	1886	var payload: Payload.Bits = .{
	1887	.base = .{ .tag = .int_unsigned },
	1888	.data = 80,
	1889	};
	1890	const u80_ty = initPayload(&payload.base);
	1891	return abiAlignment(u80_ty, target);
	1892	},
	1893	},
	1894	.c_longdouble => switch (CType.longdouble.sizeInBits(target)) {
	1895	16 => return abiAlignment(Type.f16, target),
	1896	32 => return abiAlignment(Type.f32, target),
	1897	64 => return abiAlignment(Type.f64, target),
	1898	80 => return abiAlignment(Type.f80, target),
	1899	128 => return abiAlignment(Type.f128, target),
	1900	else => unreachable,
	1901	},
1883	1902
1884	1903	.error_set,
1885	1904	.error_set_single,
...	...	@@ -2158,9 +2177,28 @@ pub const Type = extern union {
2158	2177	.f16 => return 2,
2159	2178	.f32 => return 4,
2160	2179	.f64 => return 8,
2161		.f80 => return 16,
2162	2180	.f128 => return 16,
2163		.c_longdouble => return 16,
	2181
	2182	.f80 => switch (target.cpu.arch) {
	2183	.i386 => return 12,
	2184	.x86_64 => return 16,
	2185	else => {
	2186	var payload: Payload.Bits = .{
	2187	.base = .{ .tag = .int_unsigned },
	2188	.data = 80,
	2189	};
	2190	const u80_ty = initPayload(&payload.base);
	2191	return abiSize(u80_ty, target);
	2192	},
	2193	},
	2194	.c_longdouble => switch (CType.longdouble.sizeInBits(target)) {
	2195	16 => return abiSize(Type.f16, target),
	2196	32 => return abiSize(Type.f32, target),
	2197	64 => return abiSize(Type.f64, target),
	2198	80 => return abiSize(Type.f80, target),
	2199	128 => return abiSize(Type.f128, target),
	2200	else => unreachable,
	2201	},
2164	2202
2165	2203	.error_set,
2166	2204	.error_set_single,
...	...	@@ -2349,7 +2387,7 @@ pub const Type = extern union {
2349	2387	.c_ulong => return CType.ulong.sizeInBits(target),
2350	2388	.c_longlong => return CType.longlong.sizeInBits(target),
2351	2389	.c_ulonglong => return CType.ulonglong.sizeInBits(target),
2352		.c_longdouble => 128,
	2390	.c_longdouble => return CType.longdouble.sizeInBits(target),
2353	2391
2354	2392	.error_set,
2355	2393	.error_set_single,
...	...	@@ -4772,6 +4810,13 @@ pub const Type = extern union {
4772	4810	pub const @"u8" = initTag(.u8);
4773	4811	pub const @"u32" = initTag(.u32);
4774	4812	pub const @"u64" = initTag(.u64);
	4813
	4814	pub const @"f16" = initTag(.f16);
	4815	pub const @"f32" = initTag(.f32);
	4816	pub const @"f64" = initTag(.f64);
	4817	pub const @"f80" = initTag(.f80);
	4818	pub const @"f128" = initTag(.f128);
	4819
4775	4820	pub const @"bool" = initTag(.bool);
4776	4821	pub const @"usize" = initTag(.usize);
4777	4822	pub const @"isize" = initTag(.isize);

src/value.zig+41-26

...	...	@@ -1112,6 +1112,19 @@ pub const Value = extern union {
1112	1112	}
1113	1113
1114	1114	fn floatWriteToMemory(comptime F: type, f: F, target: Target, buffer: []u8) void {
	1115	if (F == f80) {
	1116	switch (target.cpu.arch) {
	1117	.i386, .x86_64 => {
	1118	const repr = std.math.break_f80(f);
	1119	std.mem.writeIntLittle(u64, buffer[0..8], repr.fraction);
	1120	std.mem.writeIntLittle(u16, buffer[8..10], repr.exp);
	1121	// TODO set the rest of the bytes to undefined. should we use 0xaa
	1122	// or is there a different way?
	1123	return;
	1124	},
	1125	else => {},
	1126	}
	1127	}
1115	1128	const Int = @Type(.{ .Int = .{
1116	1129	.signedness = .unsigned,
1117	1130	.bits = @typeInfo(F).Float.bits,
...	...	@@ -1122,41 +1135,43 @@ pub const Value = extern union {
1122	1135
1123	1136	fn floatReadFromMemory(comptime F: type, target: Target, buffer: []const u8) F {
1124	1137	if (F == f80) {
1125		switch (target.cpu.arch.endian()) {
1126		.Little => {
1127		const TargetF80Repr = extern struct {
1128		fraction: u64,
1129		exp: u16,
1130		};
1131		const target_repr = @ptrCast(*align(1) const TargetF80Repr, buffer.ptr);
1132		const real_repr: std.math.F80Repr = .{
1133		.fraction = target_repr.fraction,
1134		.exp = target_repr.exp,
1135		};
1136		return @ptrCast(const f80, &real_repr).;
1137		},
1138		.Big => {
1139		const TargetF80Repr = extern struct {
1140		exp: u16,
1141		fraction: u64,
1142		};
1143		const target_repr = @ptrCast(*align(1) const TargetF80Repr, buffer.ptr);
1144		const real_repr: std.math.F80Repr = .{
1145		.fraction = target_repr.fraction,
1146		.exp = target_repr.exp,
1147		};
1148		return @ptrCast(const f80, &real_repr).;
1149		},
	1138	switch (target.cpu.arch) {
	1139	.i386, .x86_64 => return std.math.make_f80(.{
	1140	.fraction = std.mem.readIntLittle(u64, buffer[0..8]),
	1141	.exp = std.mem.readIntLittle(u16, buffer[8..10]),
	1142	}),
	1143	else => {},
1150	1144	}
1151	1145	}
1152	1146	const Int = @Type(.{ .Int = .{
1153	1147	.signedness = .unsigned,
1154	1148	.bits = @typeInfo(F).Float.bits,
1155	1149	} });
1156		const int = std.mem.readInt(Int, buffer[0..@sizeOf(Int)], target.cpu.arch.endian());
	1150	const int = readInt(Int, buffer[0..@sizeOf(Int)], target.cpu.arch.endian());
1157	1151	return @bitCast(F, int);
1158	1152	}
1159	1153
	1154	fn readInt(comptime Int: type, buffer: *const [@sizeOf(Int)]u8, endian: std.builtin.Endian) Int {
	1155	var result: Int = 0;
	1156	switch (endian) {
	1157	.Big => {
	1158	for (buffer) \|byte\| {
	1159	result <<= 8;
	1160	result \|= byte;
	1161	}
	1162	},
	1163	.Little => {
	1164	var i: usize = buffer.len;
	1165	while (i != 0) {
	1166	i -= 1;
	1167	result <<= 8;
	1168	result \|= buffer[i];
	1169	}
	1170	},
	1171	}
	1172	return result;
	1173	}
	1174
1160	1175	/// Asserts that the value is a float or an integer.
1161	1176	pub fn toFloat(val: Value, comptime T: type) T {
1162	1177	return switch (val.tag()) {

test/behavior/floatop.zig+4-1

...	...	@@ -5,7 +5,10 @@ const math = std.math;
5	5	const pi = std.math.pi;
6	6	const e = std.math.e;
7	7	const Vector = std.meta.Vector;
8		const has_f80_rt = @import("builtin").cpu.arch == .x86_64;
	8	const has_f80_rt = switch (builtin.cpu.arch) {
	9	.x86_64, .i386 => true,
	10	else => false,
	11	};
9	12
10	13	const epsilon_16 = 0.001;
11	14	const epsilon = 0.000001;