workaround Issue 20906 - unnecessary divide-by-zero errors when const…

[WalterBright]

…ant folding short circuits

Doesn't look like this bug will be resolved anytime soon, see dlang/dmd#11252

In the meantime, need to move forward with dlang/dmd#11236

[dlang-bot]

Thanks for your pull request, @WalterBright!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✗	20906	normal	unnecessary divide-by-zero errors when constant folding short circuits

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + druntime#3130"

[WalterBright]

Baffling log file errors that have seemingly no connection with this PR.

[MoonlightSentinel]

The azure failure is an unrelated (it's a phobos bug that rarely manifests inside of run.d).

[Geod24]

This doesn't make sense to me. The only reason to pull this would be to accept the pending changes to inline, which would mean accepting introducing a regression, which is a big no-no in everyone's book.
And Buildkite shows us that it triggers in a few projects.

[WalterBright]

The azure failure is an unrelated (it's a phobos bug that rarely manifests inside of run.d).

Is there a bugzilla for it? Any fix?

[WalterBright]

which would mean accepting introducing a regression

How so?

[MoonlightSentinel]

Is there a bugzilla for it? Any fix?

Working on it, gonna open a PR soon

[Geod24]

How so?

If you fix the bug, we can pull your DMD PR and this workaround becomes useless.
If you don't fix the bug, we shouldn't pull your DMD PR, and there's no point in pulling this workaround either.

[WalterBright]

If you don't fix the bug, we shouldn't pull your DMD PR

Why?

If you fix the bug

I could use some help with that (finding the piece of code that causes it).

[kinke]

In any case, such an ugly workaround should be restricted to DMD (version (DigitalMars)); no reason to pessimize LDC etc. because of a DMD limitation.

[WalterBright]

This can be closed when dlang/dmd#11252 passes.

@kinke this function has likely never been inlined, otherwise the failure would have showed up before.

[kinke]

this function has likely never been inlined

Just because it wasn't for DMD doesn't mean it wasn't/isn't with LDC - if it isn't clear by now, LDC does not use the DMD AST inliner at all.

[WalterBright]

No longer needed.