[Bug target/26656] Optimization flaw on conditional set of a bit.

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26656

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |target
             Target|                            |x86_64

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
flagQuestion:
.L2:
        cmpb    %bpl, (%r12,%rax)
        setb    %cl
        addl    %ecx, %ecx
        orb     %cl, (%rbx,%rax)
        addq    $1, %rax
        cmpq    $100000000, %rax
        jne     .L2
flagQuestionWorkaround:
.L7:
        cmpb    %bpl, (%r12,%rax)
        setb    %cl
        addl    %ecx, %ecx
        orb     %cl, (%rbx,%rax)
        addq    $1, %rax
        cmpq    $100000000, %rax
        jne     .L7
flagIf:
.L12:
        cmpb    %bl, (%r12,%rax)
        jnb     .L11
        orb     $2, 0(%rbp,%rax)
.L11:
        addq    $1, %rax
        cmpq    $100000000, %rax
        jne     .L12
flagIfWorkaround:
.L16:
        cmpb    %bpl, (%r12,%rax)
        setb    %cl
        addl    %ecx, %ecx
        orb     %cl, (%rbx,%rax)
        addq    $1, %rax
        cmpq    $100000000, %rax
        jne     .L16

There is not much be done with flagIf really since it is a conditional
load/store.