[Bug rtl-optimization/80491] [7 Regression] Compiler regression for long-add case.

[zimmerma+gcc at loria dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80491

Paul Zimmermann <zimmerma+gcc at loria dot fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zimmerma+gcc at loria dot fr

--- Comment #15 from Paul Zimmermann <zimmerma+gcc at loria dot fr> ---
I just checked with gcc 9.2.1 20191109 (Debian 9.2.1-19) and it seems -O1
produces better code than -O3. Is there a non-regression test?

$ gcc -S -O3 test.cc -o-
        .file   "test.cc"
        .text
        .p2align 4
        .globl  _Z3addR4pairS0_
        .type   _Z3addR4pairS0_, @function
_Z3addR4pairS0_:
.LFB0:
        .cfi_startproc
        movq    (%rsi), %rax
        xorl    %ecx, %ecx
        addq    (%rdi), %rax
        setc    %cl
        movq    8(%rsi), %rdx
        addq    8(%rdi), %rdx
        addq    %rcx, %rdx
        ret
        .cfi_endproc
.LFE0:
        .size   _Z3addR4pairS0_, .-_Z3addR4pairS0_
        .ident  "GCC: (Debian 9.2.1-19) 9.2.1 20191109"
        .section        .note.GNU-stack,"",@progbits

$ gcc -S -O1 test.cc -o-
        .file   "test.cc"
        .text
        .globl  _Z3addR4pairS0_
        .type   _Z3addR4pairS0_, @function
_Z3addR4pairS0_:
.LFB0:
        .cfi_startproc
        movq    (%rdi), %rax
        movq    8(%rsi), %rdx
        addq    (%rsi), %rax
        adcq    8(%rdi), %rdx
        ret
        .cfi_endproc
.LFE0:
        .size   _Z3addR4pairS0_, .-_Z3addR4pairS0_
        .ident  "GCC: (Debian 9.2.1-19) 9.2.1 20191109"
        .section        .note.GNU-stack,"",@progbits