assemble code and disassembled code in-consistency

[Mark Charney]

On 7/6/12 12:54 PM, H.J. Lu wrote:
> On Fri, Jul 6, 2012 at 9:47 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Jul 6, 2012 at 9:27 AM, Feng LI <nemokingdom@gmail.com> wrote:
>>> Hi folks,
>>>
>>> I have a backend hook (x86_64) for builtin function expansion, so
>>> I have this:
>>>
>>> expand_simple_binop (DImode, ASHIFT, op0,
>>>                                  GEN_INT (32),op0,1,OPTAB_DIRECT);
>>>
>>> to generate op0 = op0<<32 (op0 is the first argument of this builtin
>>> function, with type SIZE_T)
>>>
>>> The thing goes well in the assemble code, where I got:
>>>          movq    104(%rbx), %rax
>>>          salq    $32, %rax
>>>          addq    80(%rbx), %rax
>>>
>>> as expected.
>>>
>>> But at execution time, it gives me a strange behavior,
>>> So I disassemble the code,
>>>
>>> 401135:       48 8b 43 68             mov    0x68(%rbx),%rax
>>> 401140:       48 c1 e0 20             shl    $0x20,%rax
>>> 401144:       48 03 43 50             add    0x50(%rbx),%rax
>>>
>>> and it turns out salq are changed to shl which leads to the
>>> strange behavior. shl only allows shift less or equal than 31.
>>>
>> It is a binutils issue.
> Hi Peter, Andi, Mark,
>
> For some reason, binutils encodes sal the same as shl.  I'd
> like to fix it.  Will it cause any problems?
>
> Thanks.
>

SAL = SHL functionally. They are aliases. FWIW, XED
does not even have SAL; I call them all SHL.