Re: [PATCH] x86-64: always use unsigned 32-bit relocation for 32-bit addressing

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Mon, Nov 13, 2017 at 6:30 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>>> On 13.11.17 at 14:35, <hjl.tools@gmail.com> wrote:
>> On Mon, Nov 13, 2017 at 3:50 AM, Jan Beulich <JBeulich@suse.com> wrote:
>>> Except for %eip-relative addressing, where we don't have a suitable
>>> relocation type silently wrapping at the 4G boundary, consistently
>>> force use of R_X86_64_32 (in ELF terms) instead of its sign-extending
>>> counterpart. This wasn't right in case there was no base register in
>>> the addressing expression.
>>
>> Since displacement is signed, won't it generate different code?  Is there
>> a bug report to show it is necessary?
>
> I'm afraid I don't understand the question: Signed-ness of
> 32-bit quantities doesn't matter when talking of 32-bit addressing.
> If you think something is wrong here, may I ask that you take the
> tests being added and state what you would want to see be the
> expected result(s)?
>

We currently have

(BASE + INDEX * SCALE + DISP) & 0xffffffff

You want to change it to

(BASE + INDEX * SCALE + (DISP & 0xffffffff)) & 0xffffffff

Am I correct?

-- 
H.J.