Champion "Compiler intrinsics (calli, ldftn, etc)"

[gafter]

• Proposal added
• Discussed in LDM
• Decision in LDM
• Finalized (done, rejected, inactive)
• Spec'ed

See also

• Proposal: https://github.com/dotnet/csharplang/blob/master/proposals/intrinsics.md
• https://github.com/dotnet/csharplang/blob/master/meetings/2017/LDM-2017-01-11.md
• https://github.com/dotnet/csharplang/blob/master/meetings/2018/LDM-2018-09-05.md#compiler-intrinsics
• https://github.com/dotnet/csharplang/blob/master/meetings/2018/LDM-2018-09-05.md#compiler-intrinsics
• https://github.com/dotnet/csharplang/blob/master/meetings/2019/LDM-2019-01-23.md

[Unknown6656]

What are the advantages of compiler intrinsics for specific IL-opcodes instead of directly supporting inline-IL?

[orthoxerox]

@Unknown6656 you don't have to modify the parser, only the emitter, so you get to reuse type checking.

[tannergooding]

At least for calli and ldftn, the static delegate proposal (#302) would cover a way of using it outside of intrinsic support. However, the intrinsic support would still be useful for cases where users can't or don't want to change their API surface.

[MadsTorgersen]

Need more motivation to prioritize this

[MichalStrehovsky]

Need more motivation to prioritize this

@MadsTorgersen What kind of motivation? I can buy beers to anyone who implements it if they need to motivate that way. There's plenty of use cases for this - see all the people referencing the issue at dotnet/roslyn#11475.

Could implementing this be an up for grabs issue in the Roslyn repo?

[4creators]

@MichalStrehovsky @MadsTorgersen
Without any beer I could volunteer to implement it, however, due to my time limitations it could be only free time job.

[jaredpar]

Could implementing this be an up for grabs issue in the Roslyn repo?

Unlikely. We are still uncertain this is the design we want to take. I personally have a lot of reservations about the approach.

[4creators]

@jaredpar
Can you describe what kind of reservations C# team has about this proposal?

[GeirGrusom]

IL as a language feature is a little bit of a cop-out I think.