Correction: The construct gcc complains about is not
if ( a < b ) ... but if ( a < b - ( b >> 2 ) ) ... but still the same applies. The RHS of the > operator can never be negative or have an overflow on 32 bits. On Fri, 8 Mar 2019 10:40:06 +1100 Zoltan Kocsi <zol...@bendor.com.au> wrote: > Gcc 8.2.0 (arm-none-eabi) throws a warning on the following construct: > > uint32_t a; > uint16_t b; > > if ( a > b ) ... > > compaining that a signed integer is compared against an unsigned. > Of course, it is correct, as 'b' was promoted to int. > > But shouldn't it be smart enough to know that (int) b is restricted to > the range of [0,65535] which it can safely compare against the range > of [0,0xffffffffu]? > > Thanks, > > Zoltan
