Any extended integer types that exist in the implementation (C99 and C11 6.2.5).
GCC does not support any extended integer types.
twos complement, or ones complement, and whether the extraordinary value is a trap representation or an ordinary value (C99 and C11 6.2.6.2).
GCC supports only twos complement integer types, and all bit patterns are ordinary values.
integer type with the same precision (C99 and C11 6.3.1.1).
GCC does not support any extended integer types.
signed integer type when the value cannot be represented in an object of that type (C90 6.2.1.2, C99 and C11 6.3.1.3).
For conversion to a type of width N, the value is reduced modulo 2^N to be within range of the type; no signal is raised.
6.3, C99 and C11 6.5).
Bitwise operators act on the representation of the value including both the sign and value bits, where the sign bit is considered immediately above the highest-value value bit. Signed >> acts on negative numbers by sign extension.
GCC does not use the latitude given in C99 and C11 only to treat certain aspects of signed << as undefined, but this is subject to change.
GCC always follows the C99 and C11 requirement that the result of division is truncated towards zero.