[cfe-dev] [LLVMdev] [Proposal] function attribute to reduce emission of vzeroupper instructions

Rafael EspĂ­ndola rafael.espindola at gmail.com
Sat Dec 21 06:56:42 PST 2013

On 20 December 2013 21:42, Gao, Yunzhong
<yunzhong_gao at playstation.sony.com> wrote:
> Hi Rafael and Reid,
> To clarify,
> With a target-specific attribute, the LLVM IR representation will be something like this:
>   declare i32 @foo() "x86_avx"="true"
> With a target-specific metadata, the IR will be something like this:
>    declare i32 @foo() !1
>    ...
>    !1 = metadata !{metadata !"x86_avx"}
> If a backend does not understand this attribute or this metadata, it will have no effect on code generation.
> If this is what you mean, then I believe either approach will work for me.


> Do you have any opinion on the clang part of the proposal?

Just an observation that this should probably be an attribute on
function types, since I assume you want to be able to put it in
function types. Aaron can probably confirm if that is the right way to
do it.

> I plan to take the next two weeks off from work, so I probably will respond to emails only
> sporadically. I hope you have a happy holiday there too,

Thanks! Enjoy time off!

> - Gao.


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