>>62
あれあれ？こんなのあるよ

6.3.1.3 Signed and unsigned integers
1 When a value with integer type is converted to another integer type other than _Bool, if
the value can be represented by the new type, it is unchanged.
2 Otherwise, if the new type is unsigned, the value is converted by repeatedly adding or
subtracting one more than the maximum value that can be represented in the new type
until the value is in the range of the new type.49)
3 Otherwise, the new type is signed and the value cannot be represented in it; either the
result is implementation-defined or an implementation-defined signal is raised.

今回はこの3に該当するよね？処理系定義もしくはシグナルを発生するとあるけど