stage2: undefined Value generated from enum value (crash)

[g-w1]

This code generates an undefined (0xaaaaa) Value:

pub fn main() void {
    syscall0(SYS.EXITS);
}

fn syscall0(arg: SYS) void {
    _ = arg;
}

const SYS = enum(u32) {
    BAD = 1,
    EXITS = 8,
};

/home/jacob/dev/zig/src/value.zig:899:21: 0xa64c66 in value.Value.toUnsignedInt (zig1)
            else => unreachable,
                    ^
/home/jacob/dev/zig/src/codegen.zig:4921:79: 0x118c5cd in codegen.Function(std.target.Arch.x86_64).genTypedValue (zig1)
                    return MCValue{ .immediate = typed_value.val.toUnsignedInt() };
                                                                              ^
/home/jacob/dev/zig/src/codegen.zig:4953:62: 0x118d15d in codegen.Function(std.target.Arch.x86_64).genTypedValue (zig1)
                                    return self.genTypedValue(.{ .ty = enum_full.tag_ty, .val = tag_val });
                                                             ^
/home/jacob/dev/zig/src/codegen.zig:4823:65: 0x1189cb1 in codegen.Function(std.target.Arch.x86_64).resolveInst (zig1)
                        gop.value_ptr.* = try self.genTypedValue(.{
                                                                ^
/home/jacob/dev/zig/src/codegen.zig:2583:65: 0xfb2c17 in codegen.Function(std.target.Arch.x86_64).airCall (zig1)
                            const arg_mcv = try self.resolveInst(args[arg_i]);
                                                                ^
/home/jacob/dev/zig/src/codegen.zig:837:57: 0xfaa086 in codegen.Function(std.target.Arch.x86_64).genBody (zig1)
                    .call            => try self.airCall(inst),
                                                        ^

[g-w1]

Fixed by e16ddad