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Re: Is there a way to adjust alignment of DImode and DFmode?


On Thu, May 21, 2015 at 2:40 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, May 21, 2015 at 2:25 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, May 21, 2015 at 2:08 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, May 21, 2015 at 1:56 PM, Jim Wilson <jim.wilson@linaro.org> wrote:
>>>> On 05/20/2015 10:00 AM, H.J. Lu wrote:
>>>>> By default, alignment of DImode and DFmode is set to 8 bytes.
>>>>> Intel MCU psABI specifies alignment of DImode and DFmode
>>>>> to be 4 bytes. I'd like to make get_mode_alignment to return
>>>>> 32 bits for DImode and DFmode.   Is there a way to adjust alignment
>>>>> of DImode and DFmode via ADJUST_ALIGNMENT?
>>>>
>>>> I see that i386-modes.def already uses ADJUST_ALIGNMENT to change the
>>>> alignment of XFmode to 4 for ilp32 code.  ADJUST_ALIGNMENT should work
>>>> the same for DImode and DFmode.  Did you run into a problem when you
>>>> tried it?
>>>
>>> It seems to work.  I don't know why it failed for me last time.
>>>
>>
>> Now I remembered.  It doesn't work for complex and decimal
>> floating point modes:
>>
>> build/genmodes: config/i386/i386-modes.def:41: no mode "DD"
>> build/genmodes: config/i386/i386-modes.def:42: no mode "TD"
>>
>
> machmode.def has
>
> /* Allow the target to specify additional modes of various kinds.  */
> #if HAVE_EXTRA_MODES
> # include EXTRA_MODES_FILE
> #endif
>
> /* Complex modes.  */
> COMPLEX_MODES (INT);
> COMPLEX_MODES (FLOAT);
>
> /* Decimal floating point modes.  */
> DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
> DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
> DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
>
> We can't adjust any modes in i386-modes.def since they
> aren't available yet.  But we need to include i386-modes.def
> before
>
> COMPLEX_MODES (FLOAT);
>
> to get XCmode.
>
> Should we add an EXTRA_ALIGNMENTS_FILE and include it
> after all modes are created?

I opened:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66250

-- 
H.J.


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