[llvm-commits] [PATCH] Add support for fast calling convention

[Jush Lu]

*
*
*Ping.

Here are two patches, they are the same patches as last email.

The first patch “fast-isel-fastcc.patch”:
This patch adds support for fastcc, and I add test cases for {VFP, noVFP} x
{fastcc, nofastcc}.

The second patch “fast-isel-simplify-if.patch”:
This patch just simplify if statements for CallingConv::C, no functionality
changes.

I would commit these patches, please review them, thanks a lot.

Jush*


On Mon, Aug 13, 2012 at 7:59 PM, Jush Lu <jush.msn at gmail.com> wrote:

> Hi,
>
> fastcc uses FastCC_ARM_APCS (not CC_ARM_APCS) if targets don't support
> AAPCS ABI, and FastCC_ARM_APCS is specific to fastcc, that is, if we merge
> it into CallingConv::C, there will be extra checks caused
> by FastCC_ARM_APCS when we handle CallingConv::C, but CallingConv::C
> doesn't need these checks. In general, we use CallingConv::C much, and
> fastcc is rare, this will be unnecessary overhead to CallingConv::C, and we
> just move similar checks from fasctcc to CCC.
>
> For the fast-isel-fastcc.patch attached in this email, I add test cases
> for {VFP, noVFP} x {fastcc, no fastcc}, no changes for rest.
>
> Jush
>
> On Sat, Aug 11, 2012 at 2:20 AM, Renato Golin <rengolin at systemcall.org>wrote:
>
>> On 10 August 2012 12:25, Jush Lu <jush.msn at gmail.com> wrote:
>> > Hi all,
>> >
>> > As Renato's suggestion, I split the last patch into two patches.
>>
>> It was actually Chad's suggestion, I just agreed with him... :D
>>
>>
>> > 'fast-isel-fastcc.patch' is for fix, and another is for clean up.
>>
>> The clean-up is harmless, and should pose no problems. However, it
>> seems you ended up with two implementations of the same thing (sorry I
>> missed that in the first review).
>>
>> AFAIK, fastcc in ARM is the same as AAPCS, so there is no point in
>> having two similar logics for both. The original implementation,
>> though, seemed to be wrong assuming "fastcc" (like CCC) should be
>> default to APCS, rather than AAPCS.
>>
>> I think the best course of action is to common up the two
>> implementations (ie. leave the fall through as it is), by adding
>> yet-another test in the end (and on ABI check), taking (CC ==
>> CallingConv::Fast) into consideration.
>>
>> And add the working version of the tests, for completeness.
>>
>> --
>> cheers,
>> --renato
>>
>> http://systemcall.org/
>>
>
>
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