Cleaning up expand optabs code

[Mikael Pettersson]

Richard Sandiford writes:
 > Mikael Pettersson <mikpe@it.uu.se> writes:
 > > Richard Sandiford writes:
 > >  > Andreas Krebbel <krebbel@linux.vnet.ibm.com> writes:
 > >  > > On 03/22/2011 06:48 PM, Richard Henderson wrote:
 > >  > >
 > >  > >> Ok.  Watch out for other target problems this week.
 > >  > >
 > >  > > This unfortunately broke bootstrap on s390.
 > >  > 
 > >  > This is PR 48263.  Since it seems to be affecting several targets,
 > >  > and since my bootstrap seems to be taking a looong time, I'll post
 > >  > the patch here before testing has finished.
 > >  > 
 > >  > > Just copying the pre-patch behaviour fixes the problem for me:
 > >  > 
 > >  > I think we need to undo more of the patch, and leave the conversion
 > >  > outside of the new interface.
 > >  > 
 > >  > Sorry for the breakage.
 > >  > 
 > >  > Richard
 > >  > 
 > >  > 
 > >  > gcc/
 > >  > 	PR rtl-optimization/48263
 > >  > 	* optabs.c (expand_binop_directly): Reinstate convert_modes code
 > >  > 	and original commutative_p handling.  Use maybe_gen_insn.
 > >
 > > Unfortunately this fix (r171418) broke m68k-linux, see
 > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48332
 > 
 > Please try the attached
 > 
 > Richard
 > 
 > 
 > gcc/
 > 	PR rtl-optimization/48332
 > 	* optabs.c (expand_binop_directly): Set xmodeN to the target-mandated
 > 	mode of input operand N and modeN to its actual mode.

Thanks, this allowed me to build gcc-4.7 as a cross to m68k-linux again.

I'm starting a native bootstrap of gcc-4.7 head + this fix on m68k, but
that will take about 5 days to complete...

/Mikael

 > 
 > Index: gcc/optabs.c
 > ===================================================================
 > --- gcc/optabs.c	2011-03-24 17:23:05.000000000 +0000
 > +++ gcc/optabs.c	2011-03-29 14:18:02.000000000 +0100
 > @@ -1243,9 +1243,9 @@ expand_binop_directly (enum machine_mode
 >  		       rtx last)
 >  {
 >    enum insn_code icode = optab_handler (binoptab, mode);
 > -  enum machine_mode mode0 = insn_data[(int) icode].operand[1].mode;
 > -  enum machine_mode mode1 = insn_data[(int) icode].operand[2].mode;
 > -  enum machine_mode tmp_mode;
 > +  enum machine_mode xmode0 = insn_data[(int) icode].operand[1].mode;
 > +  enum machine_mode xmode1 = insn_data[(int) icode].operand[2].mode;
 > +  enum machine_mode mode0, mode1, tmp_mode;
 >    struct expand_operand ops[3];
 >    bool commutative_p;
 >    rtx pat;
 > @@ -1256,8 +1256,8 @@ expand_binop_directly (enum machine_mode
 >       if we would swap the operands, we can save the conversions.  */
 >    commutative_p = commutative_optab_p (binoptab);
 >    if (commutative_p
 > -      && GET_MODE (xop0) != mode0 && GET_MODE (xop1) != mode1
 > -      && GET_MODE (xop0) == mode1 && GET_MODE (xop1) == mode1)
 > +      && GET_MODE (xop0) != xmode0 && GET_MODE (xop1) != xmode1
 > +      && GET_MODE (xop0) == xmode1 && GET_MODE (xop1) == xmode1)
 >      {
 >        swap = xop0;
 >        xop0 = xop1;
 > @@ -1265,9 +1265,9 @@ expand_binop_directly (enum machine_mode
 >      }
 >  
 >    /* If we are optimizing, force expensive constants into a register.  */
 > -  xop0 = avoid_expensive_constant (mode0, binoptab, xop0, unsignedp);
 > +  xop0 = avoid_expensive_constant (xmode0, binoptab, xop0, unsignedp);
 >    if (!shift_optab_p (binoptab))
 > -    xop1 = avoid_expensive_constant (mode1, binoptab, xop1, unsignedp);
 > +    xop1 = avoid_expensive_constant (xmode1, binoptab, xop1, unsignedp);
 >  
 >    /* In case the insn wants input operands in modes different from
 >       those of the actual operands, convert the operands.  It would
 > @@ -1275,19 +1275,19 @@ expand_binop_directly (enum machine_mode
 >       that they're properly zero-extended, sign-extended or truncated
 >       for their mode.  */
 >  
 > -  if (GET_MODE (xop0) != mode0 && mode0 != VOIDmode)
 > -    xop0 = convert_modes (mode0,
 > -			  GET_MODE (xop0) != VOIDmode
 > -			  ? GET_MODE (xop0)
 > -			  : mode,
 > -			  xop0, unsignedp);
 > -
 > -  if (GET_MODE (xop1) != mode1 && mode1 != VOIDmode)
 > -    xop1 = convert_modes (mode1,
 > -			  GET_MODE (xop1) != VOIDmode
 > -			  ? GET_MODE (xop1)
 > -			  : mode,
 > -			  xop1, unsignedp);
 > +  mode0 = GET_MODE (xop0) != VOIDmode ? GET_MODE (xop0) : mode;
 > +  if (xmode0 != VOIDmode && xmode0 != mode0)
 > +    {
 > +      xop0 = convert_modes (xmode0, mode0, xop0, unsignedp);
 > +      mode0 = xmode0;
 > +    }
 > +
 > +  mode1 = GET_MODE (xop1) != VOIDmode ? GET_MODE (xop1) : mode;
 > +  if (xmode1 != VOIDmode && xmode1 != mode1)
 > +    {
 > +      xop1 = convert_modes (xmode1, mode1, xop1, unsignedp);
 > +      mode1 = xmode1;
 > +    }
 >  
 >    /* If operation is commutative,
 >       try to make the first operand a register.
 >