[PATCH][FastISel] Let the target decide first if it wants to materialize a constant.

[Juergen Ributzka]

I know. I have the same issue here with the list too … takes forever today.

-Juergen

On Aug 14, 2014, at 10:53 AM, Chad Rosier <mcrosier at codeaurora.org> wrote:

> I see the revert (what's up with the slow list today?).  I'll have an
> answer in a bit.  I need to step out for an hour, so we should know by 1p
> PT.
> 
> Chad
> 
> 
>> Dang, that might have been the other commit I made after this to extend
>> the addressing modes for AArch64.
>> Let me revert that commit first. How long will it take to see the results
>> of the revert?
>> 
>> Cheers,
>> Juergen
>> 
>> On Aug 14, 2014, at 9:53 AM, Chad Rosier <mcrosier at codeaurora.org> wrote:
>> 
>>> Juergen,
>>> Also, I'm seeing a large number of spec2K and spec2K6 failures after
>>> this
>>> flurry of commits.  I'm not exactly sure which one to blame, but we
>>> should
>>> consider reverting to fix the nightlies as well as allow for proper
>>> review.
>>> 
>>> Chad
>>> 
>>>> So, this was in my list of things to look at but it seems like you
>>>> went ahead and committed it without actually waiting for feedback?
>>>> 
>>>> -eric
>>>> 
>>>> On Tue, Aug 12, 2014 at 9:23 AM, Juergen Ributzka <juergen at apple.com>
>>>> wrote:
>>>>> ping :D
>>>>> 
>>>>> On Aug 7, 2014, at 2:51 PM, Juergen Ributzka <juergen at apple.com>
>>>>> wrote:
>>>>> 
>>>>>> Hi @ll,
>>>>>> 
>>>>>> I want to change the order in which FastISel tries to materialize a
>>>>>> constant.
>>>>>> 
>>>>>> Originally it would try to use a simple target-independent approach,
>>>>>> which can lead to the generation of inefficient code.
>>>>>> 
>>>>>> On X86 this would result in the use of movabsq to materialize any
>>>>>> 64bit
>>>>>> integer constant - even for simple and small values such as 0 and 1.
>>>>>> Also
>>>>>> some very funny floating-point materialization could be observed too.
>>>>>> 
>>>>>> On AArch64 it would materialize the constant 0 in a register even the
>>>>>> architecture has an actual "zero" register.
>>>>>> 
>>>>>> On ARM it would generate unnecessary mov instructions or not use mvn,
>>>>>> etc
>>>>>> 
>>>>>> I want to simply change the order and always asks the target first if
>>>>>> it likes to materialize the constant. The patches a pretty simple and
>>>>>> straight forward, but since it changes the way how FastISel works
>>>>>> with
>>>>>> respect to constants I wanted everyone affected by it to have at
>>>>>> least
>>>>>> a quick look first.
>>>>>> 
>>>>>> Thanks
>>>>>> 
>>>>>> Cheers,
>>>>>> Juergen
>>>>>> 
>>>>>> <0001-FastISel-AArch64-Cleanup-constant-materialization-co.patch><0002-FastISel-ARM-Fix-a-bug-in-the-integer-materializatio.patch><0003-FastISel-ARM-Use-MOVT-MOVW-if-the-subtarget-requests.patch><0004-FastISel-X86-Refactor-constant-materialization.-NFCI.patch><0005-FastISel-Let-the-target-decide-first-if-it-wants-to-.patch><0006-FastISel-AArch64-Make-use-of-the-zero-register-when-.patch><0007-FastISel-X86-Emit-more-efficient-instructions-for-in.patch><0008-FastISel-X86-Use-XOR-to-materialize-the-0-value.patch>
>>>>> 
>>>> 
>>> 
>>> 
>>> --
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>>> hosted by The Linux Foundation
>>> 
>> 
>> 
> 
> 
> -- 
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
>