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Re: Writing over [SP]
> From: Diego Novillo <dnovillo@google.com>
> To: Jamie Prescott <jpresss@yahoo.com>
> Cc: gcc@gcc.gnu.org
> Sent: Friday, May 15, 2009 2:44:23 PM
> Subject: Re: Writing over [SP]
>
> On Thu, May 14, 2009 at 18:18, Jamie Prescott wrote:
> >
> > This is driving me crazy. Any memory op that tries to write over [SP] get's
> automatically nuked
> > by the compiler.
> > Any offset, positive or negative, from SP, has no problems.
> > What did I do wrong this time?
>
> You need to provide a *whole* lot more information if you want us to
> be able to help you. Input program, compile flags, changes you've
> made to the compiler...
I made no changes on GCC out of my TARGET domain.
An instruction like this one:
insn = gen_move_insn(gen_rtx_MEM(SImode,
plus_constant(stack_pointer_rtx,
offset)),
gen_rtx_REG(SImode, reg));
emit_insn(insn);
Does not emit anything if "offset" == 0, while works for every offset != 0.
Instructions are just discarded.
Will investigate deeper on this as soon as I completed the port to 4.4, that is
currently giving me some headache.
- Jamie