On January 11, 2016 5:36:33 PM GMT+01:00, Bernd Schmidt <bschm...@redhat.com> wrote: >On 01/11/2016 05:33 PM, Matthew Wahab wrote: >> >> The case I'm trying to fix has (short)abs((int)short_var). I'd >thought >> that if >> abs(short_var) was undefined because the result couldn't be >represented >> then the type >> conversion from int to short would also be undefined. In fact, it's >> implementation >> defined and S4.5 of the GCC manual says that the value is reduced >until >> it can be >> represented. So (short)abs((int)short_var) will produce a value when >> abs(short_var) is undefined meaning this transformation isn't >correct. >> I'll drop this patch. > >Maybe we could have an optab and corresponding internal function for an > >abs that's always defined.
I'd like to have ABSU_EXPR (or allow unsigned result on ABS_EXPR). Richard. > >Bernd
