Yuya Watari <watari.y...@gmail.com> writes: > On Thu, Nov 7, 2019 at 3:10 PM Kyotaro Horiguchi > <horikyota....@gmail.com> wrote: >> + if (unlikely(!FLOAT8_FITS_IN_INT32(num)) || isnan(num)) >> If compiler doesn't any fancy, num is fed to an arithmetic before >> checking if it is NaN. That seems have a chance of exception.
> Thank you for pointing it out. That's my mistake. I fixed it and > attached the patch. Actually, that mistake is very old --- the existing functions tested isnan() last for a long time. I agree that testing isnan() first is safer, but it seems that the behavior of throwing an exception for comparisons on NaN is rarer than one might guess from the C spec. Another issue in the patch as it stands is that the FITS_IN_ macros require the input to have already been rounded with rint(), else they'll give the wrong answer for values just a bit smaller than -PG_INTnn_MIN. The existing uses of the technique did that, and interval_mul already did too, but I had to adjust pgbench. This is largely a documentation failure: not only did you fail to add any commentary about the new macros, but you removed most of the commentary that had been in-line in the existing usages. I fixed those things and pushed it. regards, tom lane