Re: Reload generating memory ref in memory ref

[Richard Henderson <rth at redhat dot com>]

Ian Lance Taylor wrote:
> Michael Eager <eager@eagercon.com> writes:
>
> > I'm running into a situation where reload is replacing
> > a pseudo-register in an insn with a memory reference.
> > The problem is that this is happening in a memory ref.
> >
> > The initial pattern is something like
> >
> > (set (reg/v:SI 1) (mem/s:SI (plus:SI
> > 	(reg/f:SI 30)
> > 	(const_int 4)) ))
> >
> > After reload, this becomes
> >
> > (set (reg/v:SI 1) (mem/s:SI (plus:SI
> > 	(mem/f/c:SI (plus:SI (reg/f:SI 19) (const_int -2))
> >         (const_int 4))
> >
> > The reg-equiv for pseudo-reg 30 is the mem ref in the middle.
> >
> > Any idea about why this might be happening, or, better,
> > how to get reload to generate a load from reg-equiv to a reg
> > rather than replace the pseudo-reg with the reg-equiv?
>
> This is a normal occurrence during the course of reload.  If this
> escapes from reload, it suggests that your GO_IF_LEGITIMATE_ADDRESS
> macro is incorrectly accepting a MEM as a memory address, or that your
> insn operand predicate is somehow accepting it.

Another possibility is illegal rtl sharing.


r~