authorgravatar for jacobly@ziglang.orgJacob Young <jacobly@ziglang.org> 2023-04-02 05:15:26-04:00
committergravatar for jacobly@ziglang.orgJacob Young <jacobly@ziglang.org> 2023-04-02 05:16:46-04:00
log0e289cc8269c9c18358b511564718972808d2efe
tree2e8cd639a8e419af4acea83a99d2a39f1c614665
parentc713c863896d4ef6b4fd0817e8db59f5992b2303

x86_64: implement large add/sub with overflow

4 files changed, 26 insertions(+), 14 deletions(-)

src/arch/x86_64/CodeGen.zig+23-13
......@@ -1857,18 +1857,15 @@ fn airAddSubShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
18571857 const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
18581858 const tag = self.air.instructions.items(.tag)[inst];
18591859 const ty = self.air.typeOf(bin_op.lhs);
1860 const abi_size = ty.abiSize(self.target.*);
18611860 switch (ty.zigTypeTag()) {
18621861 .Vector => return self.fail("TODO implement add/sub/shl with overflow for Vector type", .{}),
18631862 .Int => {
1864 if (abi_size > 8) {
1865 return self.fail("TODO implement add/sub/shl with overflow for Ints larger than 64bits", .{});
1866 }
1867
18681863 try self.spillEflagsIfOccupied();
18691864
18701865 if (tag == .shl_with_overflow) {
18711866 try self.spillRegisters(&.{.rcx});
1867 // cf/of don't work for shifts other than 1
1868 return self.fail("TODO implement shl_with_overflow for x86_64", .{});
18721869 }
18731870
18741871 const partial: MCValue = switch (tag) {
......@@ -1885,16 +1882,29 @@ fn airAddSubShlWithOverflow(self: *Self, inst: Air.Inst.Index) !void {
18851882 };
18861883
18871884 const int_info = ty.intInfo(self.target.*);
1888
18891885 if (int_info.bits >= 8 and math.isPowerOfTwo(int_info.bits)) {
1890 self.eflags_inst = inst;
1891 break :result .{ .register_overflow = .{
1892 .reg = partial.register,
1893 .eflags = switch (int_info.signedness) {
1894 .unsigned => .c,
1895 .signed => .o,
1886 const cc: Condition = switch (int_info.signedness) {
1887 .unsigned => .c,
1888 .signed => .o,
1889 };
1890 switch (partial) {
1891 .register => |reg| {
1892 self.eflags_inst = inst;
1893 break :result .{ .register_overflow = .{ .reg = reg, .eflags = cc } };
18961894 },
1897 } };
1895 else => {},
1896 }
1897
1898 const abi_size = @intCast(i32, ty.abiSize(self.target.*));
1899 const dst_mcv = try self.allocRegOrMem(inst, false);
1900 try self.genSetStack(
1901 Type.u1,
1902 dst_mcv.stack_offset - abi_size,
1903 .{ .eflags = cc },
1904 .{},
1905 );
1906 try self.genSetStack(ty, dst_mcv.stack_offset, partial, .{});
1907 break :result dst_mcv;
18981908 }
18991909
19001910 const tuple_ty = self.air.typeOfIndex(inst);
test/behavior/eval.zig+1
......@@ -488,6 +488,7 @@ test "comptime bitwise operators" {
488488test "comptime shlWithOverflow" {
489489 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
490490 if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
491 if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
491492
492493 const ct_shifted = @shlWithOverflow(~@as(u64, 0), 16)[0];
493494 var a = ~@as(u64, 0);
test/behavior/int128.zig-1
......@@ -40,7 +40,6 @@ test "undefined 128 bit int" {
4040}
4141
4242test "int128" {
43 if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
4443 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
4544 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
4645 if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
test/behavior/math.zig+2
......@@ -1237,6 +1237,8 @@ fn testShlTrunc(x: u16) !void {
12371237}
12381238
12391239test "exact shift left" {
1240 if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
1241
12401242 try testShlExact(0b00110101);
12411243 comptime try testShlExact(0b00110101);
12421244}