Re: [x86_64 PATCH take #2] PR target/106450: Tweak timode_remove_non_convertible_regs.

[Uros Bizjak <ubizjak@gmail.com>]

On Sat, Jul 30, 2022 at 11:42 AM Roger Sayle <roger@nextmovesoftware.com> wrote:
>
>
> Many thanks to H.J. for pointing out a better idiom for traversing
> the USEs (and also DEFs) of TImode registers in an instruction.
>
> This revised patched has been tested on x86_64-pc-linux-gnu with
> make bootstrap and make -k check, both with and without
> --target_board=unix{-m32}, with no new failures.  Ok for mainline?
>
>
> 2022-07-30  Roger Sayle  <roger@nextmovesoftware.com>
>             H.J. Lu  <hjl.tools@gmail.com>
>
> gcc/ChangeLog
>         PR target/106450
>         * config/i386/i386-features.cc (timode_check_non_convertible_regs):
>         Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
>         (timode_remove_non_convertible_regs): Update comment.
>         Call timode_check_non_convertible_reg on all TImode register
>         DEFs and USEs in each instruction.
>
> gcc/testsuite/ChangeLog
>         PR target/106450
>         * gcc.target/i386/pr106450.c: New test case.

LGTM.

Thanks,
Uros.

>
>
> Thanks (H.J. and Uros),
> Roger
> --
>
> > -----Original Message-----
> > From: H.J. Lu <hjl.tools@gmail.com>
> > Sent: 28 July 2022 17:55
> > To: Roger Sayle <roger@nextmovesoftware.com>
> > Cc: GCC Patches <gcc-patches@gcc.gnu.org>
> > Subject: Re: [x86_64 PATCH] PR target/106450: Tweak
> > timode_remove_non_convertible_regs.
> >
> > On Thu, Jul 28, 2022 at 9:43 AM Roger Sayle <roger@nextmovesoftware.com>
> > wrote:
> > >
> > > This patch resolves PR target/106450, some more fall-out from more
> > > aggressive TImode scalar-to-vector (STV) optimizations.  I continue to
> > > be caught out by how far TImode STV has diverged from DImode/SImode
> > > STV, and therefore requires additional (unexpected) tweaking.  Many
> > > thanks to H.J. Lu for pointing out timode_remove_non_convertible_regs
> > > needs to be extended to handle XOR (and other new operations).
> > >
> > > Unhelpfully the comment above this function states that it's the
> > > TImode version of "remove_non_convertible_regs", which doesn't exist
> > > anymore, so I've resurrected an explanatory comment from the git history.
> > > By refactoring the checks for hard regs and already "marked" regs into
> > > timode_check_non_convertible_regs itself, all its callers are
> > > simplified.  This patch then uses GET_RTX_CLASS to generically handle
> > > unary and binary operations, calling timode_check_non_convertible_regs
> > > on each TImode register operand in the single_set's SET_SRC.
> > >
> > > This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> > > and make -k check, both with and without --target_board=unix{-m32},
> > > with no new failures.  Ok for mainline?
> > >
> > >
> > > 2022-07-28  Roger Sayle  <roger@nextmovesoftware.com>
> > >
> > > gcc/ChangeLog
> > >         PR target/106450
> > >         * config/i386/i386-features.cc (timode_check_non_convertible_regs):
> > >         Do nothing if REGNO is set in the REGS bitmap, or is a hard reg.
> > >         (timode_remove_non_convertible_regs): Update comment.
> > >         Call timode_check_non_convertible_regs on all register operands
> > >         of supported (binary and unary) operations.
> >
> > Should we use
> >
> > df_ref ref;
> > FOR_EACH_INSN_USE (ref, insn)
> >    if (!DF_REF_REG_MEM_P (ref))
> >      timode_check_non_convertible_regs (candidates, regs,
> >               DF_REF_REGNO (ref));
> >
> > to check each use?
> >
> > > gcc/testsuite/ChangeLog
> > >         PR target/106450
> > >         * gcc.target/i386/pr106450.c: New test case.
> > >
> > >
> > > Thanks in advance,
> > > Roger
> > > --
> > --
> > H.J.