[Bug target/70734] __builtin_add_overflow emits poor code on x86-64

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70734

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
gcc-6 produces

        .cfi_startproc
        addl    %esi, %edi
        movl    %edi, (%rdx)
        jo      .L9
        rep ret
.L9:
        pushq   %rax
        .cfi_def_cfa_offset 16
        call    abort
        .cfi_endproc

is that what you wanted?