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CBE: implement popCount, byteSwap, bitReverse for ints <= 128 bits

Browse Source 
This folds the airCountZeroes() code from
226fcd7c709ec664c5d883042cf7beb3026f66cb back into airBuiltinCall(),
since most of these builtins happen to require the same arguments and
can be unified under a common function signature.
This commit is contained in:
Daniele Cocca 2022-03-13 00:43:51 +00:00
parent 87744a7ea9
commit d0277a3d17
6 changed files with 107 additions and 28 deletions
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31
src/codegen/c.zig
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@ -1711,8 +1711,8 @@ fn genBody(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail, OutO
.memcpy => try airMemcpy(f, inst),
.set_union_tag => try airSetUnionTag(f, inst),
.get_union_tag => try airGetUnionTag(f, inst),
.clz => try airCountZeroes(f, inst, "clz"),
.ctz => try airCountZeroes(f, inst, "ctz"),
.clz => try airBuiltinCall(f, inst, "clz"),
.ctz => try airBuiltinCall(f, inst, "ctz"),
.popcount => try airBuiltinCall(f, inst, "popcount"),
.byte_swap => try airBuiltinCall(f, inst, "byte_swap"),
.bit_reverse => try airBuiltinCall(f, inst, "bit_reverse"),
@ -3352,23 +3352,6 @@ fn airPtrToInt(f: *Function, inst: Air.Inst.Index) !CValue {
fn airBuiltinCall(f: *Function, inst: Air.Inst.Index, fn_name: [*:0]const u8) !CValue {
if (f.liveness.isUnused(inst)) return CValue.none;
const inst_ty = f.air.typeOfIndex(inst);
const local = try f.allocLocal(inst_ty, .Const);
const ty_op = f.air.instructions.items(.data)[inst].ty_op;
const writer = f.object.writer();
const operand = try f.resolveInst(ty_op.operand);
// TODO implement the function in zig.h and call it here
try writer.print(" = {s}(", .{fn_name});
try f.writeCValue(writer, operand);
try writer.writeAll(");\n");
return local;
}
fn airCountZeroes(f: *Function, inst: Air.Inst.Index, fn_name: [*:0]const u8) !CValue {
if (f.liveness.isUnused(inst)) return CValue.none;
const inst_ty = f.air.typeOfIndex(inst);
const local = try f.allocLocal(inst_ty, .Const);
const operand = f.air.instructions.items(.data)[inst].ty_op.operand;
@ -3376,13 +3359,17 @@ fn airCountZeroes(f: *Function, inst: Air.Inst.Index, fn_name: [*:0]const u8) !C
const target = f.object.dg.module.getTarget();
const writer = f.object.writer();
const zig_bits = operand_ty.intInfo(target).bits;
_ = toCIntBits(zig_bits) orelse
const int_info = operand_ty.intInfo(target);
_ = toCIntBits(int_info.bits) orelse
return f.fail("TODO: C backend: implement integer types larger than 128 bits", .{});
const signed_type = switch (int_info.signedness) {
.signed => "true",
.unsigned => "false",
};
try writer.print(" = zig_{s}(", .{fn_name});
try f.writeCValue(writer, try f.resolveInst(operand));
try writer.print(", {d});\n", .{zig_bits});
try writer.print(", {d}, {s});\n", .{ int_info.bits, signed_type });
return local;
}

96
src/link/C/zig.h
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@ -502,8 +502,20 @@ zig_shl_sat_s(int, int, ((sizeof(int )) * CHAR_BIT - 1))
zig_shl_sat_s(long, long, ((sizeof(long )) * CHAR_BIT - 1))
#define zig_bitsizeof(T) (CHAR_BIT * sizeof(T))
#define zig_bit_mask(T, bit_width) \
((bit_width) == 128 \
? ((T)(((uint128_t) 0xffffffffffffffff) << 64 | \
(uint128_t) 0xffffffffffffffff)) \
: (((T)1 << (T)(bit_width)) - 1))
static inline uint128_t zig_sign_extend(uint128_t value, uint128_t zig_type_bit_width) {
const uint128_t m = (uint128_t)1 << (zig_type_bit_width - 1);
return (value ^ m) - m;
}
static inline int zig_clz(unsigned long long value, uint8_t zig_type_bit_width, bool signed_type) {
(void)signed_type; // unused
static inline int zig_clz(uint64_t value, uint8_t zig_type_bit_width) {
if (value == 0) return zig_type_bit_width;
if (zig_type_bit_width <= zig_bitsizeof(unsigned int))
return (__builtin_clz(value) - zig_bitsizeof(unsigned int) + zig_type_bit_width);
@ -512,9 +524,89 @@ static inline int zig_clz(uint64_t value, uint8_t zig_type_bit_width) {
return (__builtin_clzll(value) - zig_bitsizeof(unsigned long long) + zig_type_bit_width);
}
static inline int zig_ctz(uint64_t value, uint8_t zig_type_bit_width) {
static inline int zig_ctz(unsigned long long value, uint8_t zig_type_bit_width, bool signed_type) {
(void)signed_type; // unused
if (value == 0) return zig_type_bit_width;
if (zig_type_bit_width <= zig_bitsizeof(unsigned int)) return __builtin_ctz(value);
if (zig_type_bit_width <= zig_bitsizeof(unsigned long)) return __builtin_ctzl(value);
return __builtin_ctzll(value);
}
static inline int zig_popcount(unsigned long long value, uint8_t zig_type_bit_width, bool signed_type) {
(void)signed_type; // unused
const unsigned long long mask = zig_bit_mask(unsigned long long, zig_type_bit_width);
if (zig_type_bit_width <= zig_bitsizeof(unsigned int))
return __builtin_popcount(value & mask);
if (zig_type_bit_width <= zig_bitsizeof(unsigned long))
return __builtin_popcountl(value & mask);
return __builtin_popcountll(value & mask);
}
static inline uint128_t zig_byte_swap(uint128_t value, uint8_t zig_type_bit_width, bool signed_type) {
if (zig_type_bit_width <= 8) return value;
if (zig_type_bit_width <= 16) return __builtin_bswap16(value);
if (zig_type_bit_width <= 32) {
const uint32_t swapped = __builtin_bswap32(value) >> (32 - zig_type_bit_width);
return (signed_type ? zig_sign_extend(swapped, zig_type_bit_width) : swapped);
}
if (zig_type_bit_width <= 64) {
const uint64_t swapped = __builtin_bswap64(value) >> (64 - zig_type_bit_width);
return (signed_type ? zig_sign_extend(swapped, zig_type_bit_width) : swapped);
}
const uint128_t mask = zig_bit_mask(uint128_t, zig_type_bit_width);
const uint128_t hi = __builtin_bswap64((uint64_t)(value >> 64));
const uint128_t lo = __builtin_bswap64((uint64_t)value);
const uint128_t swapped = (((lo << 64 | hi) >> (128 - zig_type_bit_width))) & mask;
return (signed_type ? zig_sign_extend(swapped, zig_type_bit_width) : swapped);
}
static inline uint128_t zig_bit_reverse(uint128_t value, uint8_t zig_type_bit_width, bool signed_type) {
static const uint128_t reverse_lut[256] = {
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0,
0x30, 0xb0, 0x70, 0xf0, 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8, 0x04, 0x84, 0x44, 0xc4,
0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc,
0x3c, 0xbc, 0x7c, 0xfc, 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2, 0x0a, 0x8a, 0x4a, 0xca,
0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6,
0x36, 0xb6, 0x76, 0xf6, 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe, 0x01, 0x81, 0x41, 0xc1,
0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9,
0x39, 0xb9, 0x79, 0xf9, 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5, 0x0d, 0x8d, 0x4d, 0xcd,
0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3,
0x33, 0xb3, 0x73, 0xf3, 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb, 0x07, 0x87, 0x47, 0xc7,
0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf,
0x3f, 0xbf, 0x7f, 0xff
};
const uint128_t mask = zig_bit_mask(uint128_t, zig_type_bit_width);
const uint128_t swapped = zig_byte_swap(value, zig_type_bit_width, signed_type);
const uint128_t reversed = (
(reverse_lut[(swapped >> 0x78) & 0xff] << 0x78) |
(reverse_lut[(swapped >> 0x70) & 0xff] << 0x70) |
(reverse_lut[(swapped >> 0x68) & 0xff] << 0x68) |
(reverse_lut[(swapped >> 0x60) & 0xff] << 0x60) |
(reverse_lut[(swapped >> 0x58) & 0xff] << 0x58) |
(reverse_lut[(swapped >> 0x50) & 0xff] << 0x50) |
(reverse_lut[(swapped >> 0x48) & 0xff] << 0x48) |
(reverse_lut[(swapped >> 0x40) & 0xff] << 0x40) |
(reverse_lut[(swapped >> 0x38) & 0xff] << 0x38) |
(reverse_lut[(swapped >> 0x30) & 0xff] << 0x30) |
(reverse_lut[(swapped >> 0x28) & 0xff] << 0x28) |
(reverse_lut[(swapped >> 0x20) & 0xff] << 0x20) |
(reverse_lut[(swapped >> 0x18) & 0xff] << 0x18) |
(reverse_lut[(swapped >> 0x10) & 0xff] << 0x10) |
(reverse_lut[(swapped >> 0x08) & 0xff] << 0x08) |
(reverse_lut[(swapped >> 0x00) & 0xff] << 0x00));
const uint128_t result =
(reversed >> (zig_type_bit_width < 8 ? 8 - zig_type_bit_width : 0)) & mask;
return (signed_type ? zig_sign_extend(result, zig_type_bit_width) : result);
}

2
test/behavior.zig
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@ -139,6 +139,7 @@ test {
_ = @import("behavior/eval.zig");
_ = @import("behavior/export_self_referential_type_info.zig");
_ = @import("behavior/int128.zig");
_ = @import("behavior/popcount.zig");
_ = @import("behavior/translate_c_macros.zig");
_ = @import("behavior/union_with_members.zig");
@ -147,7 +148,6 @@ test {
_ = @import("behavior/atomics.zig");
_ = @import("behavior/export.zig");
_ = @import("behavior/maximum_minimum.zig");
_ = @import("behavior/popcount.zig");
_ = @import("behavior/saturating_arithmetic.zig");
_ = @import("behavior/widening.zig");
_ = @import("behavior/bugs/2114.zig");

2
test/behavior/bitreverse.zig
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@ -5,7 +5,6 @@ const minInt = std.math.minInt;
test "@bitReverse large exotic integer" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
// Currently failing on stage1 for big-endian targets
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
@ -14,7 +13,6 @@ test "@bitReverse large exotic integer" {
test "@bitReverse" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;

1
test/behavior/byteswap.zig
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@ -4,7 +4,6 @@ const expect = std.testing.expect;
test "@byteSwap integers" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;

3
test/behavior/popcount.zig
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@ -1,3 +1,4 @@
const builtin = @import("builtin");
const std = @import("std");
const expect = std.testing.expect;
const expectEqual = std.testing.expectEqual;
@ -45,6 +46,8 @@ fn testPopCountIntegers() !void {
}
test "@popCount vectors" {
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
comptime try testPopCountVectors();
try testPopCountVectors();
}