On 09/27/16 16:10, Florian Weimer wrote: > * Bernd Edlinger: > >>> “0 << 0” is used in a similar context, to create a zero constant for a >>> multi-bit subfield of an integer. >>> >>> This example comes from GDB, in bfd/elf64-alpha.c: >>> >>> | insn = INSN_ADDQ | (16 << 21) | (0 << 16) | (0 << 0); >>> >> >> Of course that is not a boolean context, and will not get a warning. >> >> Question is if "if (1 << 0)" is possibly a miss-spelled "if (1 < 0)". >> >> Maybe 1 and 0 come from macro expansion.... > > But what's the intent of treating 1 << 0 and 0 << 0 differently in the > patch, then? >
I am not sure if it was a good idea. I saw, we had code of the form bool flag = 1 << 2; another value LOOKUP_PROTECT is 1 << 0, and bool flag = 1 << 0; would at least not overflow the allowed value range of a boolean. Bernd.
