Add overrides for __simd intrinsics

[ibuclaw]

This is blocking dlang/dmd#7065

[dlang-bot]

Thanks for your pull request, @ibuclaw!

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[ibuclaw]

Replaced with templates.

Can't add unittests because of https://issues.dlang.org/show_bug.cgi?id=17751

[wilzbach]

Looks reasonable to me, but I'm no expert on simD

[ibuclaw]

Marking as blocked. I'll rebase and add unittests so the compiler ICE gets triggered (so that we'll know when dmd is fixed).

@MartinNowak is this fine from a high level design?

@WalterBright don't suppose you can have a look at the backens related ICE?

[WalterBright]

I don't know what the rationale of this is. There's no bugzilla issue referenced, no explanation here, no comments in the code?

[ibuclaw]

@WalterBright see dmd pr and linked bug there. I want to make it illegal to implicitly cast to void vector, but these intrinsics block the patch.

[JinShil]

Can't add unittests because of https://issues.dlang.org/show_bug.cgi?id=17751

Bug 17751 was fixed with dlang/dmd#7216. Is this still "Blocked"?

[ibuclaw]

Fix turned my proposal into an error. If only dmd did constant propagation it would not be an error though...

The imm8 template should instead have the following signature.

pure @safe V1 simd(XMM opcode, ubyte imm8, V1, V2)(V1 op1, V2 op2)
    if (is(V1 == __vector) && is(V2 == __vector))

[PetarKirov]

LGTM as well.

[PetarKirov]

I've restarted CircleCI, hopefully the failure was intermittent.

[wilzbach]

I've restarted CircleCI, hopefully the failure was intermittent.

Probably caused by a very old config file. I rebased to upstream/master. This typically helps for old PRs.

[ibuclaw]

Raises Eyebrows.

I think I will have to go through some of the tests though to make sure they are OK. I don't recall whether coverage is complete here, I can see a couple commented out tests.

I guess I can switch over the XMM test file in dmd to use these templates and see what blows up. :-)