On Mon, Dec 9, 2013 at 3:49 PM, Kenneth Zadeck <zad...@naturalbridge.com> wrote: > On 12/08/2013 05:35 AM, Richard Biener wrote: >> >> Richard Sandiford <rdsandif...@googlemail.com> wrote: >>> >>> Kenneth Zadeck <zad...@naturalbridge.com> writes: >>>>>>>> >>>>>>>> #define WIDE_INT_MAX_ELTS \ >>>>>>>> - ((4 * MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \ >>>>>>>> - / HOST_BITS_PER_WIDE_INT) >>>>>>>> + (((MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \ >>>>>>>> + / HOST_BITS_PER_WIDE_INT) + 1) >>>>>>> >>>>>>> I think this should be: >>>>>>> >>>>>>> (MAX_BITSIZE_MODE_ANY_INT / HOST_BITS_PER_WIDE_INT + 1) >>>>>>> >>>>>>> We only need an extra HWI if MAX_BITSIZE_MODE_ANY_INT is an exact >>> >>> multiple >>>>>>> >>>>>>> of HOST_BITS_PER_WIDE_INT. >>>>>> >>>>>> we will do this later when some other issues that Eric B raised are >>> >>> settled. >>>>> >>>>> I think you're talking about defining MAX_BITSIZE_MODE_ANY_INT as >>>>> MAX_SIZE_MODE_ANY_INT * BITS_PER_UNIT, but that's orthogonal to the >>>>> change above. IMO it doesn't make sense to both round up the >>> >>> division >>>>> >>>>> and also add 1 to the result. So I think we should make this change >>>>> regardless of whatever follows. >>>>> >>>>> Looks good to me otherwise, thanks. >>>>> >>>>> Richard >>>>> >>>> so this one works the way you want. While it is true the the >>> >>> problems >>>> >>>> are disjoint, the solution will likely evolving change the same lines >>> >>> of >>>> >>>> source in two different ways. >>> >>> Well, if we're changing the definition of WIDE_INT_MAX_ELTS now (and we >>> are) >>> I think we should change it to something that makes sense. All we want >>> is >>> 1 extra bit. We don't need to round up the size and then add a whole >>> HWI on top. Doing that will potentially pessimise targets that don't >>> need anything beyond SImode. >> >> I agree. >> >> Richard. > > Done, ok to commit?
+ early examination of the target's mode file. The WIDE_INT_MAX_ELTS + can accomodate at least 1 more bit so that unsigned numbers of that + mode can be represented. Note that it is still possible to create + fixed_wide_ints that have precisions greater than + MAX_BITSIZE_MODE_ANY_INT. This can be useful when representing a + double-width multiplication result, for example. */ #define WIDE_INT_MAX_ELTS \ - ((4 * MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \ - / HOST_BITS_PER_WIDE_INT) + (((MAX_BITSIZE_MODE_ANY_INT + HOST_BITS_PER_WIDE_INT - 1) \ + / HOST_BITS_PER_WIDE_INT)) + that doesn't reserve 1 more bit, it just rounds up. For one more bit you need to add 1, so #define WIDE_INT_MAX_ELTS \ + (((MAX_BITSIZE_MODE_ANY_INT + 1 + HOST_BITS_PER_WIDE_INT - 1) \ + / HOST_BITS_PER_WIDE_INT)) no? Otherwise ok. Thanks, Richard. > kenny > > >>> It's not like I can approve the patch anyway though, so I'll leave it >>> there. >>> >>> Thanks, >>> Richard >> >> >
