On Thu, Jun 19, 2025 at 2:55 AM Roger Sayle <ro...@nextmovesoftware.com> wrote:
>
>
> Looks good to me. Sorry for any inconvenience.
> Cheers,
> Roger
>
> > -----Original Message-----
> > From: Hongtao Liu <crazy...@gmail.com>
> > Sent: 19 June 2025 08:01
> > To: H.J. Lu <hjl.to...@gmail.com>
> > Cc: GCC Patches <gcc-patches@gcc.gnu.org>; Uros Bizjak <ubiz...@gmail.com>;
> > Hongtao Liu <hongtao....@intel.com>; Roger Sayle
> > <ro...@nextmovesoftware.com>
> > Subject: Re: [PATCH v4] x86: Enable *mov<mode>_(and|or) only for -Oz
> >
> > On Wed, Jun 18, 2025 at 6:38 PM H.J. Lu <hjl.to...@gmail.com> wrote:
> > >
> > > commit ef26c151c14a87177d46fd3d725e7f82e040e89f
> > > Author: Roger Sayle <ro...@nextmovesoftware.com>
> > > Date: Thu Dec 23 12:33:07 2021 +0000
> > >
> > > x86: PR target/103773: Fix wrong-code with -Oz from pop to memory.
> > >
> > > added "*mov<mode>_and" and extended "*mov<mode>_or" to transform
> > "mov
> > > $0,mem" to the shorter "and $0,mem" and "mov $-1,mem" to the shorter
> > > "or $-1,mem" for -Oz. But the new pattern:
> > >
> > > (define_insn "*mov<mode>_and"
> > > [(set (match_operand:SWI248 0 "memory_operand" "=m")
> > > (match_operand:SWI248 1 "const0_operand"))
> > > (clobber (reg:CC FLAGS_REG))]
> > > "reload_completed"
> > > "and{<imodesuffix>}\t{%1, %0|%0, %1}"
> > > [(set_attr "type" "alu1")
> > > (set_attr "mode" "<MODE>")
> > > (set_attr "length_immediate" "1")])
> > >
> > > and the extended pattern:
> > >
> > > (define_insn "*mov<mode>_or"
> > > [(set (match_operand:SWI248 0 "nonimmediate_operand" "=rm")
> > > (match_operand:SWI248 1 "constm1_operand"))
> > > (clobber (reg:CC FLAGS_REG))]
> > > "reload_completed"
> > > "or{<imodesuffix>}\t{%1, %0|%0, %1}"
> > > [(set_attr "type" "alu1")
> > > (set_attr "mode" "<MODE>")
> > > (set_attr "length_immediate" "1")])
> > >
> > > aren't guarded for -Oz. As a result, "and $0,mem" and "or $-1,mem"
> > > are generated without -Oz.
> > >
> > > 1. Change *mov<mode>_and" to define_insn_and_split and split it to
> > > "mov $0,mem" if not -Oz.
> > > 2. Change "*mov<mode>_or" to define_insn_and_split and split it to
> > > "mov $-1,mem" if not -Oz.
> > > 3. Don't transform "mov $-1,reg" to "push $-1; pop reg" for -Oz since
> > > it should be transformed to "or $-1,reg".
> >
> > Ok for me, but please hold for a few days in case Uros or Roger has any
> > comments.
> >
> > >
> > > gcc/
> > >
> > > PR target/120427
> > > * config/i386/i386.md (*mov<mode>_and): Changed to
> > > define_insn_and_split. Split it to "mov $0,mem" if not -Oz.
> > > (*mov<mode>_or): Changed to define_insn_and_split. Split it to "mov
> > > $-1,mem" if not -Oz.
> > > (peephole2): Don't transform "mov $-1,reg" to "push $-1; pop reg"
> > > for -Oz since it will be transformed to "or $-1,reg".
> > >
> > > gcc/testsuite/
> > >
> > > PR target/120427
> > > * gcc.target/i386/cold-attribute-4.c: Compile with -Oz.
> > > * gcc.target/i386/pr120427-1.c: New test.
> > > * gcc.target/i386/pr120427-2.c: Likewise.
> > > * gcc.target/i386/pr120427-3.c: Likewise.
> > > * gcc.target/i386/pr120427-4.c: Likewise.
> > >
> > >
> > > --
> > > H.J.
> >
> >
> >
> > --
> > BR,
> > Hongtao
>
OK to backport it to release branches?
Thanks.
--
H.J.
