[LLVMdev] RFC: Tail call optimization X86

[Evan Cheng]

Yes please.

Evan
On Oct 5, 2007, at 11:55 AM, Arnold Schwaighofer wrote:

>
> On 5 Oct 2007, at 20:47, Evan Cheng wrote:
>
>>
>> On Oct 5, 2007, at 10:56 AM, Arnold Schwaighofer wrote:
>>
>>>
>>>> We can set a policy of treating fastcc external functions
>>>> as c functions. Then there is no chance of introducing ABI
>>>> incompatibility.
>>> this means limiting tail call opt to protected/invisible functions
>>> within a module?
>>> a little limiting i think.
>>
>> It makes sense to be extra careful at this point. The  policy can be
>> changed when we enable tail call optimization by default.
>>>
>>> but i think if it is documented that there will be a incompatibility
>>> between
>>> modules compiled with tailcallopt on/off that is okay?
>>> and this would only happen if someone other than llvm-gcc used llvm
>>> as a backend
>>> anyway.
>>
>> Documentation isn't going to be enough. We will do everything
>> possible to ensure there isn't abi incompatibility. But at this
>> point, it's important the patch does not impact codegen in any way
>> when tail call optimization is off. This allows us to get a true
>> sense of the performance impact.
>>
>
> okay then i'll make tailcallopt switch stack adjusting behaviour?
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