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CBE: implement clz, ctz for ints <= 128 bits

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This commit is contained in:
Daniele Cocca 2022-03-11 11:48:11 +00:00
parent 6dcfbfbfb2
commit 226fcd7c70
3 changed files with 54 additions and 4 deletions
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24
src/codegen/c.zig
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@ -1708,8 +1708,8 @@ 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 airBuiltinCall(f, inst, "clz"),
.ctz => try airBuiltinCall(f, inst, "ctz"),
.clz => try airCountZeroes(f, inst, "clz"),
.ctz => try airCountZeroes(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"),
@ -3349,6 +3349,26 @@ fn airBuiltinCall(f: *Function, inst: Air.Inst.Index, fn_name: [*:0]const u8) !C
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;
const operand_ty = f.air.typeOf(operand);
const target = f.object.dg.module.getTarget();
const writer = f.object.writer();
const zig_bits = operand_ty.intInfo(target).bits;
_ = toCIntBits(zig_bits) orelse
return f.fail("TODO: C backend: implement integer types larger than 128 bits", .{});
try writer.print(" = zig_{s}(", .{fn_name});
try f.writeCValue(writer, try f.resolveInst(operand));
try writer.print(", {d});\n", .{zig_bits});
return local;
}
fn airCmpxchg(f: *Function, inst: Air.Inst.Index, flavor: [*:0]const u8) !CValue {
const ty_pl = f.air.instructions.items(.data)[inst].ty_pl;
const extra = f.air.extraData(Air.Cmpxchg, ty_pl.payload).data;

18
src/link/C/zig.h
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@ -500,3 +500,21 @@ zig_shl_sat_s(isize, intptr_t, ((sizeof(intptr_t)) * CHAR_BIT - 1))
zig_shl_sat_s(short, short, ((sizeof(short )) * CHAR_BIT - 1))
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))
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);
if (zig_type_bit_width <= zig_bitsizeof(unsigned long))
return (__builtin_clzl(value) - zig_bitsizeof(unsigned long) + 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) {
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);
}

16
test/behavior/math.zig
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@ -65,7 +65,6 @@ test "@clz" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
try testClz();
comptime try testClz();
@ -76,6 +75,20 @@ fn testClz() !void {
try expect(testOneClz(u8, 0b00001010) == 4);
try expect(testOneClz(u8, 0b00011010) == 3);
try expect(testOneClz(u8, 0b00000000) == 8);
}
test "@clz big ints" {
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
try testClzBigInts();
comptime try testClzBigInts();
}
fn testClzBigInts() !void {
try expect(testOneClz(u128, 0xffffffffffffffff) == 64);
try expect(testOneClz(u128, 0x10000000000000000) == 63);
}
@ -130,7 +143,6 @@ test "@ctz" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
try testCtz();
comptime try testCtz();