On Tue, Jul 29, 2025 at 11:37 PM Hongtao Liu <crazy...@gmail.com> wrote:
>
> On Wed, Jul 30, 2025 at 11:45 AM H.J. Lu <hjl.to...@gmail.com> wrote:
> >
> > commit 4c80062d7b8c272e2e193b8074a8440dbb4fe588
> > Author: H.J. Lu <hjl.to...@gmail.com>
> > Date: Sun May 25 07:40:29 2025 +0800
> >
> > x86: Enable *mov<mode>_(and|or) only for -Oz
> >
> > disabled transformation from "movq $-1,reg" to "pushq $-1; popq reg" for
> > -Oz. But for legacy integer registers, the former is 4 bytes and the
> > latter is 3 bytes. Enable such transformation for -Oz.
> Ok.
Pushed. OK to backport to release branches?
> >
> > gcc/
> >
> > PR target/120427
> > * config/i386/i386.md (peephole2): Transform "movq $-1,reg" to
> > "pushq $-1; popq reg" for -Oz if reg is a legacy integer register.
> >
> > gcc/testsuite/
> >
> > PR target/120427
> > * gcc.target/i386/pr120427-5.c: New test.
> >
> > Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> > ---
> > gcc/config/i386/i386.md | 3 ++-
> > gcc/testsuite/gcc.target/i386/pr120427-5.c | 10 ++++++++++
> > 2 files changed, 12 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr120427-5.c
> >
> > diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> > index eb526997584..a50475bdaf4 100644
> > --- a/gcc/config/i386/i386.md
> > +++ b/gcc/config/i386/i386.md
> > @@ -2968,7 +2968,8 @@ (define_peephole2
> > (match_operand:SWI248 1 "const_int_operand"))]
> > "optimize_insn_for_size_p () && optimize_size > 1
> > && operands[1] != const0_rtx
> > - && operands[1] != constm1_rtx
> > + && (operands[1] != constm1_rtx
> > + || (<MODE>mode == DImode && LEGACY_INT_REG_P (operands[0])))
> > && IN_RANGE (INTVAL (operands[1]), -128, 127)
> > && !ix86_red_zone_used
> > && REGNO (operands[0]) != SP_REG"
> > diff --git a/gcc/testsuite/gcc.target/i386/pr120427-5.c
> > b/gcc/testsuite/gcc.target/i386/pr120427-5.c
> > new file mode 100644
> > index 00000000000..7199aef7924
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr120427-5.c
> > @@ -0,0 +1,10 @@
> > +/* { dg-do compile { target { ! ia32 } } } */
> > +/* { dg-options "-Oz" } */
> > +
> > +long long
> > +func1 (void)
> > +{
> > + return -1;
> > +}
> > +/* { dg-final { scan-assembler-times "pushq\[ \\t\]+\\\$-1" 1 } } */
> > +/* { dg-final { scan-assembler-times "popq\[ \\t\]+%rax" 1 } } */
> > --
> > 2.50.1
> >
>
>
> --
> BR,
> Hongtao
--
H.J.
