On Fri, Feb 9, 2024 at 5:24 PM Nathan Bossart <nathandboss...@gmail.com> wrote:
> On Fri, Feb 09, 2024 at 08:52:26AM +0100, Mats Kindahl wrote: > > Here is a new version introducing pg_cmp_s32 and friends and use them > > instead of the INT_CMP macro introduced before. It also moves the > > definitions to common/int.h and adds that as an include to all locations > > using these functions. > > Thanks for the new version of the patch. > > > Note that for integers with sizes less than sizeof(int), C standard > > conversions will convert the values to "int" before doing the arithmetic, > > so no casting is *necessary*. I did not force the 16-bit functions to > > return -1 or 1 and have updated the comment accordingly. > > It might not be necessary, but this is one of those places where I would > add casting anyway to make it abundantly clear what we are expecting to > happen and why it is safe. > I'll add it. > > The types "int" and "size_t" are treated as s32 and u32 respectively > since > > that seems to be the case for most of the code, even if strictly not > > correct (size_t can be an unsigned long int for some architecture). > > Why is it safe to do this? > > > - return ((const SPLITCOST *) a)->cost - ((const SPLITCOST *) > b)->cost; > > + return INT_CMP(((const SPLITCOST *) a)->cost, ((const SPLITCOST *) > b)->cost); > > The patch still contains several calls to INT_CMP. > I'll fix it. > > > > +/*------------------------------------------------------------------------ > > + * Comparison routines for integers > > + > *------------------------------------------------------------------------ > > + */ > > I'd suggest separating this part out to a 0001 patch to make it easier to > review. The 0002 patch could take care of converting the existing qsort > comparators. > Ok. Will split it out into two patches. > > > +static inline int > > +pg_cmp_s16(int16 a, int16 b) > > +{ > > + return a - b; > > +} > > + > > +static inline int > > +pg_cmp_u16(uint16 a, uint16 b) > > +{ > > + return a - b; > > +} > > + > > +static inline int > > +pg_cmp_s32(int32 a, int32 b) > > +{ > > + return (a > b) - (a < b); > > +} > > + > > +static inline int > > +pg_cmp_u32(uint32 a, uint32 b) > > +{ > > + return (a > b) - (a < b); > > +} > > + > > +static inline int > > +pg_cmp_s64(int64 a, int64 b) > > +{ > > + return (a > b) - (a < b); > > +} > > + > > +static inline int > > +pg_cmp_u64(uint64 a, uint64 b) > > +{ > > + return (a > b) - (a < b); > > +} > > As suggested above, IMHO we should be rather liberal with the casting to > ensure it is abundantly clear what is happening here. > Ok. > > -- > Nathan Bossart > Amazon Web Services: https://aws.amazon.com >