ping https://gcc.gnu.org/ml/gcc-patches/2016-07/msg01867.html
Thanks, Prathamesh On 28 July 2016 at 19:05, Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> wrote: > On 8 June 2016 at 19:53, Richard Biener <rguent...@suse.de> wrote: >> On Fri, 3 Jun 2016, Jim Wilson wrote: >> >>> On Mon, May 30, 2016 at 12:45 AM, Richard Biener <rguent...@suse.de> wrote: >>> > Joseph - do you know sth about why there's not a full set of divmod >>> > libfuncs in libgcc? >>> >>> Because udivmoddi4 isn't a libfunc, it is a helper function for the >>> div and mov libfuncs. Since we can compute the signed div and mod >>> results from udivmoddi4, there was no need to also add a signed >>> version of it. It was given a libfunc style name so that we had the >>> option of making it a libfunc in the future, but that never happened. >>> There was no support for calling any divmod libfunc until it was added >>> as a special case to call an ARM library (not libgcc) function. This >>> happened here >>> >>> 2004-08-09 Mark Mitchell <m...@codesourcery.com> >>> >>> * config.gcc (arm*-*-eabi*): New target. >>> * defaults.h (TARGET_LIBGCC_FUNCS): New macro. >>> (TARGET_LIB_INT_CMP_BIASED): Likewise. >>> * expmed.c (expand_divmod): Try a two-valued divmod function as a >>> last resort. >>> ... >>> * config/arm/arm.c (arm_init_libfuncs): New function. >>> (arm_compute_initial_eliminatino_offset): Return HOST_WIDE_INT. >>> (TARGET_INIT_LIBFUNCS): Define it. >>> ... >>> >>> Later, two ports added their own divmod libfuncs, but I don't see any >>> evidence that they were ever used, since there is no support for >>> calling divmod other than the expand_divmod last resort code that only >>> triggers for ARM. >>> >>> It is only now that Prathamesh is adding gimple support for divmod >>> operations that we need to worry about getting this right, without >>> breaking the existing ARM library support or the existing udivmoddi4 >>> support. >> >> Ok, so as he is primarily targeting the special arm divmod libcall >> I suppose we can live with special-casing libcall handling to >> udivmoddi3. It would be nice to not lie about divmod availablilty >> as libcall though... - it looks like the libcall is also guarded >> on TARGET_HAS_NO_HW_DIVIDE (unless it was available historically >> like on x86). >> >> So not sure where to go from here. > Hi, > I have attached patch, which is rebased on trunk. > Needed to update divmod-7.c, which now gets transformed to divmod > thanks to your code-hoisting patch -;) > We still have the issue of optab_libfunc() returning non-existent > libcalls. As in previous patch, I am checking > explicitly for "__udivmoddi4", with a FIXME note. > I hope that's okay for now ? > > Bootstrapped and tested on x86_64-unknown-linux-gnu, > armv8l-unknown-linux-gnueabihf. > Bootstrap+test in progress on i686-linux-gnu. > Cross-tested on arm*-*-*. > > Thanks, > Prathamesh >> >> Richard.
