Re: [edk2-devel] Why is specified -mno-sse on clang x64?

["Gary Zibrat" <gzibrat@google.com>]

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I've messed around with it locally and nothing seemed to stop working.
Would there be any interest in adding a newer clang configuration with
-mno-sse removed?

On Thu, Apr 4, 2019 at 1:12 PM Andrew Fish <afish@apple.com> wrote:

>
>
> On Apr 4, 2019, at 1:09 PM, Gary Zibrat via Groups.Io <
> gzibrat=google.com@groups.io> wrote:
>
> It seems like the "-mno-mmx -msoft-float -mno-implicit-float" part of the
> flags should be enough to handle that now.
> Is it ok to take -mno-sse out (in my local branch) for new versions of
> clang without having to worry about silent failures?
> Since EFIAPI uses the windows ABI, it should be ok to use XMM registers
> for integer operations.
> '
>
>
> Gary,
>
> Conceptually it should be OK. But obviously no one has tested it :).
>
> Thanks,
>
> Andrew Fish
>
>
> On Thu, Apr 4, 2019 at 1:00 PM Andrew Fish <afish@apple.com> wrote:
>
>> Gary,
>>
>> The edk2 is freestanding UEFI firmware and the runtime does not support
>> floating point exceptions.
>>
>> I think a long time ago there was an optimization bug and the -mno-sse
>> fixed it.
>>
>> The UEFI x64 ABI is Windows like and not Sys V like.
>>
>> Thanks,
>>
>> Andrew Fish
>>
>> On Apr 4, 2019, at 10:13 AM, Gary Zibrat via Groups.Io <
>> gzibrat=google.com@groups.io> wrote:
>>
>> Does anyone know why -mno-sse is specified on Clang x64?
>>
>> https://github.com/tianocore/edk2/commit/6f756db5ea057ff10dd168c7627163cec046a3d9
>> There doesn't seem to be a corresponding flag for other compilers.
>>
>> I ask because a commit in LLVM breaks compilation of EDK2:
>> https://reviews.llvm.org/rL357317#change-QSW9B7DqCGUI
>>
>>
>> 
>
>
>

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