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Re: Reload question
- From: Bernd Schmidt <bernds at redhat dot com>
- To: Mark Mitchell <mark at codesourcery dot com>
- Cc: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>,"gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Fri, 26 Jul 2002 12:18:10 +0100 (BST)
- Subject: Re: Reload question
On Thu, 25 Jul 2002, Mark Mitchell wrote:
> > In reload, after doing register allocation, we do, in "reload()":
> >
> > That mutates the instruction in place, with the possible result that
> > it is no longer recognizable.
> >
> > Who is supposed to be responsible for making the instruction
> > recognizable again?
> >
> > Reload itself. The insn won't match its constraints.
>
> But this happens *at the end* of reload. Search for:
>
> PUT_CODE (reg, MEM)
>
> in reload1.c.
>
> So, where in reload is the instruction supposed to be checked to see
> that it is safe to make this transmogrification?
find_reloads. If the modification isn't safe, we'll make a reload for
the operand and thus ensure that when we get to the code that modifies
pseudos into MEMs, the transformation is correct.
Bernd