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.
>
> 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
