[PATCH] [fast-isel] x86_64 FastLowerArguments

[Jan Voung]

On Mon, Feb 25, 2013 at 10:01 AM, Chad Rosier <mcrosier at apple.com> wrote:

>
> On Feb 22, 2013, at 5:05 PM, Jan Voung <jvoung at chromium.org> wrote:
>
> +  // Only handle simple cases. i.e. Up to 6 i32/i64 scalar arguments.
> +  unsigned Idx = 1;
> +  for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
> +       I != E; ++I, ++Idx) {
> +    if (Idx > 6)
> +      return false;
> +
> +    if (F->getAttributes().hasAttribute(Idx, Attribute::InReg) ||
> +        F->getAttributes().hasAttribute(Idx, Attribute::StructRet) ||
> +        F->getAttributes().hasAttribute(Idx, Attribute::ByVal))
> +      return false;
>
> Do parameters with the nest attribute need to be checked too?  The
> CC_X86_64_C .td definition has special treatment for that, using r10 as the
> static chain register.
>
>
> Yes, thanks.
>

I wonder if these multiple attribute checks get optimized to decent/fast
code by the compiler.  Some of attributes can be pretty rare for x86-64
(e.g., InReg?)?


>
> Also, would it be worth adding a test that checks that N basic blocks were
> truly selected by fast isel, according to the "-stats" output?
>
>
> I've added a new llc flag, -fast-isel-abort-args, which is the same as
> fast-isel-abort, but is for formal argument lowering only.
>
> Revised patch attached.  Test case added that uses the new
> -fast-isel-abort-args option.
>
>
Thanks, looks pretty good.


>  Thanks for the feedback, Jan.
>
>  Chad
>
>
>
>
>
>
> On Fri, Feb 22, 2013 at 3:34 PM, Chad Rosier <mcrosier at apple.com> wrote:
>
>> All,
>> The attached patch implements a basic version of FastLowerArguments for
>> x86 fast-isel.  This is analogous to Evan's commit r174855, but for x86 of
>> course.  Please have a look (especially those familiar with x86 calling
>> conventions).
>>
>>  Regards,
>>   Chad
>>
>>
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130225/5399def1/attachment.html>