Re: Optimizations on long long multiply/divide on PowerPC32 don't work

[Franz Sirl <Franz.Sirl-kernel@lauterbach.com>]

At 10:14 10.12.2001, you wrote:
>On Mon, Dec 10, 2001 at 12:54:44AM -0800, Richard Henderson wrote:
> > GCC knows how to do this.  It will do this if the target supports
> > all of these operations on 64 bit data types and it considers them
> > to be cheap enough.
>
>How irritating.  I do not like the taste of crow.
>
>While the above is true, powerpc apparently has a rather cheap 32-bit
>divide instruction which throws off the heuristics in this case.
>
>
>r~
>
>
>
>Index: expmed.c
>===================================================================
>RCS file: /cvs/gcc/gcc/gcc/expmed.c,v
>retrieving revision 1.97
>diff -c -p -d -r1.97 expmed.c
>*** expmed.c    2001/11/20 04:12:11     1.97
>--- expmed.c    2001/12/10 09:07:20
>*************** expand_divmod (rem_flag, code, mode, op0
>*** 3271,3277 ****
>                       goto fail1;
>                   }
>                 else if (EXACT_POWER_OF_2_OR_ZERO_P (d)
>!                       && (rem_flag ? smod_pow2_cheap : sdiv_pow2_cheap))
>                   ;
>                 else if (EXACT_POWER_OF_2_OR_ZERO_P (abs_d))
>                   {
>--- 3271,3286 ----
>                       goto fail1;
>                   }
>                 else if (EXACT_POWER_OF_2_OR_ZERO_P (d)
>!                       && (rem_flag ? smod_pow2_cheap : sdiv_pow2_cheap)
>!                       /* ??? The cheap metric is computed only for
>!                           word_mode.  If this operation is wider, this may
>!                           not be so.  Assume true if the optab has an
>!                           expander for this mode.  */
>!                       && (((rem_flag ? smod_optab : sdiv_optab)
>!                             ->handlers[(int) compute_mode].insn_code
>!                             != CODE_FOR_nothing)
>!                            || (sdivmod_optab->handlers[(int) compute_mode]
>!                               .insn_code != CODE_FOR_nothing)))
>                   ;
>                 else if (EXACT_POWER_OF_2_OR_ZERO_P (abs_d))
>                   {


May I move that one to the branch for 3.0.4? Bootstrapped and regtested on 
powerpc-linux-gnu and x86-linux-gnu.

Franz.