[llvm-dev] VMOVNTDQ in LLVM

Stephen Canon via llvm-dev
2017-09-28T13:36:01Z

This thread from last year has some additional detail regarding the hazards of
aggressive MOVNT generation if you’re interested:

http://lists.llvm.org/pipermail/llvm-dev/2016-May/098980.html
<http://lists.llvm.org/pipermail/llvm-dev/2016-May/098980.html>

– Steve

> On Sep 28, 2017, at 9:31 AM, Stephen Canon via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>
> What code did you write where you expected VMOVNTDQ to be generated?
>
> The x86 MOVNT instructions are something of an attractive nuisance. There
are cases where they are beneficial, but those cases are much less common and
harder to characterize than you might expect. LLVM is deliberately conservative
about using MOVNT (IIRC it’s currently only generated if you explicitly ask for
it by using intrinsics).
>
> – Steve
>
>> On Sep 28, 2017, at 9:10 AM, hameeza ahmed via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>>
>> Hello, i am using llvm 4.0 i am generating intel avx code. But in code
i dont find VMOVNTDQ instruction. Why is that so? When does this instruction
generated?
>>
>>
>> Please clarify.
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