Reload generate invalid instruction on ppc64

[Segher Boessenkool]

On Tue, Aug 05, 2014 at 01:32:00PM +0930, Alan Modra wrote:
> On Mon, Aug 04, 2014 at 05:54:04PM -0700, Carrot Wei wrote:
> > Another problem is in the definition of insn pattern "*movdi_internal64".
> > 
> > (define_insn "*movdi_internal64"
> >   [(set (match_operand:DI 0 "nonimmediate_operand"
> > "=Y,r,r,r,r,r,?m,?*d,?*d,r,*h,*h,r,?*wg,r,?*wm")
> >         (match_operand:DI 1 "input_operand"
> > "r,Y,r,I,L,nF,d,m,d,*h,r,0,*wg,r,*wm,r"))]
> >   "TARGET_POWERPC64
> >    && (gpc_reg_operand (operands[0], DImode)
> >        || gpc_reg_operand (operands[1], DImode))"
> > 
> > The predicates of this insn pattern allow the moving of an integer to
> > VSX register, but there is no constraint allow this case. Can this
> > cause problem in reload?
> 
> Probably, just as you found with fprs.  The underlying issue is that
> the operand predicates don't match the operand constraints.  What's
> more, you can't make them match without breaking up the insn, or
> adding a whole lot of extra alternatives.

Can you disallow this in the condition of the pattern, just like it
already requires at least one of the operands to be gpc_reg_operand?


Segher