numberLiteral

fn numberLiteral(gz: *GenZir, ri: ResultInfo, node: Ast.Node.Index, source_node: Ast.Node.Index, sign: Sign) InnerError!Zir.Inst.Ref {
    const astgen = gz.astgen;
    const tree = astgen.tree;
    const num_token = tree.nodeMainToken(node);
    const bytes = tree.tokenSlice(num_token);

    const result: Zir.Inst.Ref = switch (std.zig.parseNumberLiteral(bytes)) {
        .int => |num| switch (num) {
            0 => if (sign == .positive) .zero else return astgen.failTokNotes(
                num_token,
                "integer literal '-0' is ambiguous",
                .{},
                &.{
                    try astgen.errNoteTok(num_token, "use '0' for an integer zero", .{}),
                    try astgen.errNoteTok(num_token, "use '-0.0' for a floating-point signed zero", .{}),
                },
            ),
            1 => {
                // Handle the negation here!
                const result: Zir.Inst.Ref = switch (sign) {
                    .positive => .one,
                    .negative => .negative_one,
                };
                return rvalue(gz, ri, result, source_node);
            },
            else => try gz.addInt(num),
        },
        .big_int => |base| big: {
            const gpa = astgen.gpa;
            var big_int = try std.math.big.int.Managed.init(gpa);
            defer big_int.deinit();
            const prefix_offset: usize = if (base == .decimal) 0 else 2;
            big_int.setString(@backingInt(base), bytes[prefix_offset..]) catch |err| switch (err) {
                error.InvalidCharacter => unreachable, // caught in `parseNumberLiteral`
                error.InvalidBase => unreachable, // we only pass 16, 8, 2, see above
                error.OutOfMemory => |e| return e,
            };

            const limbs = big_int.limbs[0..big_int.len()];
            assert(big_int.isPositive());
            break :big try gz.addIntBig(limbs);
        },
        .float => {
            const unsigned_float_number = std.fmt.parseFloat(f128, bytes) catch |err| switch (err) {
                error.InvalidCharacter => unreachable, // validated by `parseNumberLiteral`
            };
            const float_number = switch (sign) {
                .negative => -unsigned_float_number,
                .positive => unsigned_float_number,
            };
            // If the value fits into a f64 without losing any precision, store it that way.
            @setFloatMode(.strict);
            const smaller_float: f64 = @floatCast(float_number);
            const bigger_again: f128 = smaller_float;
            if (bigger_again == float_number) {
                const result = try gz.addFloat(smaller_float);
                return rvalue(gz, ri, result, source_node);
            }
            // We need to use 128 bits. Break the float into 4 u32 values so we can
            // put it into the `extra` array.
            const int_bits: u128 = @bitCast(float_number);
            const result = try gz.addPlNode(.float128, node, Zir.Inst.Float128{
                .piece0 = @truncate(int_bits),
                .piece1 = @truncate(int_bits >> 32),
                .piece2 = @truncate(int_bits >> 64),
                .piece3 = @truncate(int_bits >> 96),
            });
            return rvalue(gz, ri, result, source_node);
        },
        .failure => |err| return astgen.failWithNumberError(err, num_token, bytes),
    };

    if (sign == .positive) {
        return rvalue(gz, ri, result, source_node);
    } else {
        const negated = try gz.addUnNode(.negate, result, source_node);
        return rvalue(gz, ri, negated, source_node);
    }
}