Re: [PATCH] tcg: Add 'signed' bit to typecodes

[Richard Henderson]

On 2/16/22 17:39, Keith Packard wrote:
> Commit 7319d83a (tcg: Combine dh_is_64bit and dh_is_signed to
> dh_typecode) converted the tcg type system to a 3-bit field from two
> separate 1-bit fields. This subtly lost the 'signed' information from
> the types as it uses the dh_alias macro to reduce the types down to
> basic machine types. However, the dh_alias macro also discards sign
> information, aliasing 's32' to 'i32'.

The signed information is still there, merged with the typecode:

#define dh_typecode_void 0
#define dh_typecode_noreturn 0
#define dh_typecode_i32 2
#define dh_typecode_s32 3
#define dh_typecode_i64 4
#define dh_typecode_s64 5
#define dh_typecode_ptr 6

Note that is_signed is bit 0.

But I can see that dh_alias_s32 hides it -- definitely a bug there.



r~