On Wed, Jul 03, 2024 at 02:24:19PM +0200, Jakub Jelinek wrote:
> > >From 40023cac83562a1451aba550533d042fec1c144e Mon Sep 17 00:00:00 2001
> > From: Richard Biener <rguent...@suse.de>
> > Date: Tue, 11 Jun 2024 13:11:08 +0200
> > Subject: [PATCH] middle-end/115426 - wrong gimplification of "rm" asm output
> > operand
> > To: gcc-patches@gcc.gnu.org
> >
> > When the operand is gimplified to an extract of a register or a
> > register we have to disallow memory as we otherwise fail to
> > gimplify it properly. Instead of
> >
> > __asm__("" : "=rm" __imag <r>);
> >
> > we want
> >
> > __asm__("" : "=rm" D.2772);
> > _1 = REALPART_EXPR <r>;
> > r = COMPLEX_EXPR <_1, D.2772>;
> >
> > otherwise SSA rewrite will fail and generate wrong code with 'r'
> > left bare in the asm output.
> >
> > PR middle-end/115426
> > * gimplify.cc (gimplify_asm_expr): Handle "rm" output
> > constraint gimplified to a register (operation).
> >
> > * gcc.dg/pr115426.c: New testcase.
>
> LGTM, thanks.
Actually, wonder if that assert won't trigger on something invalid like
"=i" (__imag__ r)
which previously got rejected only during expansion.
So maybe instead of the assert just do your new handling just for allows_reg
&& allows_mem and leave the rest as before.
Jakub
