[Bug c/98418] Valid integer constant expressions based on expressions that trigger -Wshift-overflow are treated as non-constants

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98418

--- Comment #1 from Andrew Pinski  ---
Shifting into the sign bit is problematic. I cant remember the exact rules.
Using ull is valid though.

[Bug c/98418] Valid integer constant expressions based on expressions that trigger -Wshift-overflow are treated as non-constants

[pskocik at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98418

--- Comment #2 from pskocik at gmail dot com ---
You're right. The bug was in my code.

struct foo { unsigned bit: (0xll<<40)!=0; };

is indeed UB due to http://port70.net/~nsz/c/c11/n1570.html#6.5.7p4, but

struct foo { unsigned bit: (0xull<<40)!=0; };

isn't and GCC accepts it without complaint.

Apologies for the false alarm.

[Bug c/98418] Valid integer constant expressions based on expressions that trigger -Wshift-overflow are treated as non-constants

[pskocik at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98418

pskocik at gmail dot com changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |INVALID

--- Comment #3 from pskocik at gmail dot com ---
You're right. The bug was in my code.

struct foo { unsigned bit: (0xll<<40)!=0; };

is indeed UB due to http://port70.net/~nsz/c/c11/n1570.html#6.5.7p4, but

struct foo { unsigned bit: (0xull<<40)!=0; };

isn't and GCC accepts it without complaint.

Apologies for the false alarm.