[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 --- Comment #6 from Daniel Lundin --- Call it what you will, either way there is nothing here that's "so large that it is unsigned". The main point is that the diagnostic message is wrong. typeof(18446744073709551615) x = -1; Gives a 128 bit integer type with the value -1. If it was "so large that it is unsigned" then this would have resulted in an unsigned type with an unsigned value. The diagnostic message is plain wrong and misleading.
[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 --- Comment #5 from joseph at codesourcery dot com --- Also, for it to become an extended integer type, it would be necessary to define integer constant suffixes and implement printf / scanf support in the library, because is now required to provide intN_t / uintN_t when there is a matching standard or extended integer type, so would be required to provide int128_t / uint128_t, which in turn would require the corresponding and macros, so requiring constant suffixes and printf / scanf support.
[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 --- Comment #4 from Jonathan Wakely --- (In reply to Daniel Lundin from comment #3) > gcc behaves just like required too, since `__int128` ought to be one of the > extended integer types and it is signed. But it's not an extended integer type, see comment 2. I think that will change for C23, which allows intmax_t to be be defined to long long even if there are larger extended integer types. But in GCC today, there are no extended integer types.
[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 Daniel Lundin changed: What|Removed |Added CC||daniel.lundin.mail at gmail dot co ||m --- Comment #3 from Daniel Lundin --- This is a bug as in the wrong text is displayed in the diagnostic message. gcc picks `__int128` and it is not an unsigned type. Decimal integer constants use the the quoted list in 6.4.4.1: `int` then `long` then `long long`. Therefore this normative text (from C99 to C23) applies: "If all of the types in the list for the constant are signed, the extended integer type shall be signed." gcc behaves just like required too, since `__int128` ought to be one of the extended integer types and it is signed. I would guess this message is some remain from C90 where extended integer types didn't exist. Compiling with -std=c90 adds an additional warning "warning: this decimal constant is unsigned only in ISO C90". It would appear that this is the correct warning that should always be displayed. Seems to be a minor bug that occurred during the switch (gcc 5.0.0) from gnu90 to gnu11 as default option.
[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 --- Comment #2 from Andrew Pinski --- __int128 is not an extended integer type in the C sense. The main reason is because intmax_t is not defined as __int128.
[Bug c/84764] Wrong warning "so large that it is unsigned" for __int128 constant
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 --- Comment #1 from Pascal Cuoq --- I meant "the warning implies that the constant is typed as unsigned long long...".
