Treat f16 as a u16 in ABI

[cijiugechu]

Part1 of #825 .

[antoyo]

Sorry, I missed this PR (feel free to ping me after some time when this happens).

I would be more comfortable merging this if at least one of the following parts (2 to 6) was implemented as well as some CI for this (not sure what would be the best way to test this).

[cijiugechu]

Sorry, I missed this PR (feel free to ping me after some time when this happens).

I would be more comfortable merging this if at least one of the following parts (2 to 6) was implemented as well as some CI for this (not sure what would be the best way to test this).

Thanks for taking a look!
That makes sense. I'm already working on implementing part 2 and 5 on this branch, so I'll push an update to this PR once those are ready.

[antoyo]

Since the CI passed on the last commit, was that ready for review?

[rustbot]

☔ The latest upstream changes (possibly #899) made this pull request unmergeable. Please resolve the merge conflicts.

[tgross35]

I'm only reading the description here and not the code: this only takes effect when GCC doesn't already support f16, right?

[antoyo]

Yes, that's indeed for targets where f16 is not supported.
This PR is the first steps towards having #825, which follows your idea.