status on NewGVN?

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1

Greetings,

I just found a bug in NewGVN: https://bugs.llvm.org/show_bug.cgi?id=35839

I noticed that it’s off by default in clang.

I’m going to turn it off by default in zig too, since it has a bug.

What’s the current status? Are we trying to move towards using it by default in llvm 6.0.0? 7.0.0?

Regards,

Andrew Kelley
http://ziglang.org/

2

Greetings,

I just found a bug in NewGVN: 35839 – assertion failure in NewGVN: Value number changed after main loop completed

I suspect this is a dupe of one of the three bugs we know about.

I noticed that it's off by default in clang.

Yup.

I'm going to turn it off by default in zig too, since it has a bug.

Every pass in LLVM has bugs :slight_smile:

What's the current status? Are we trying to move towards using it by
default in llvm 6.0.0? 7.0.0?

I was the main contributor. I took on a new role and no longer have time to
push on it, and i don't suspect i will for at least 6-8 months, if not
longer.
I suspect at some point it will become important enough for someone else to
push on it again.

3

Is there an umbrella PR or something that could help organise what someone would have to do/take on in order for it to be enabled? Outstanding design issues or critical blocking bugs etc.

Amara

4

Hi Amara,

5

Yes, the bug tracks it, and there are one or two major issues. I have patches half done for them, and am more than happy to give guidance/help in getting them done (and i’ve done this successfully with 3 interns so far :P)

6

I would be happy to look into some of the remaining issues. Could you provide some pointers?

Cheers,

Florian