f16_f128: enable some more tests in Miri

[RalfJung]

For some reason, a bunch of tests were disabled in Miri that don't use any fancy intrinsics. Let's enable them.

I verified this with ./x miri library/core --no-doc -- float.

r? @tgross35

[tgross35]

I think the history here is on me; the equivalent for target_has_reliable_f16_math used to be a config in std's build.rs, and was set to true there when running with miri. I moved it from build.rs to a compiler config at some point, and since then it's not getting enabled when we are running with miri.

Is there any way to detect miri within rustc? If so, this could be updated here

rust/compiler/rustc_interface/src/util.rs

Lines 49 to 60 in 0c0c58b

	if tf_cfg.has_reliable_f16 {
	cfg.insert((sym::target_has_reliable_f16, None));
	}
	if tf_cfg.has_reliable_f16_math {
	cfg.insert((sym::target_has_reliable_f16_math, None));
	}
	if tf_cfg.has_reliable_f128 {
	cfg.insert((sym::target_has_reliable_f128, None));
	}
	if tf_cfg.has_reliable_f128_math {
	cfg.insert((sym::target_has_reliable_f128_math, None));
	}

rather than needing to update all the places that config is used.

[RalfJung]

Is there any way to detect miri within rustc?

Can the compiler check if miri is set in the cfg variables?

[tgross35]

Based on the description at

rust/compiler/rustc_session/src/config/cfg.rs

Lines 36 to 41 in 0c0c58b

	/// The parsed `--cfg` options that define the compilation environment of the
	/// crate, used to drive conditional compilation.
	///
	/// An `FxIndexSet` is used to ensure deterministic ordering of error messages
	/// relating to `--cfg`.
	pub type Cfg = FxIndexSet<(Symbol, Option<Symbol>)>;

I was thinking it could just check the cfg arg in the function I linked. Haven't tested though, figured you may know off the top of your head :)

(I could see the argument that we shouldn't be string matching cfg usually, but I think it's probably fine for the temporary config here if it works)

[RalfJung]

I don't know that cfg code at all, sorry.^^

[tgross35]

This is better than the status quo so let's merge it. I'd still like to check if miri happens to conveniently be in that cfg: &mut Cfg so we can avoid this in the future, but haven't gotten a chance to poke this yet.

View changes since this review

[tgross35]

@bors r+ rollup

[bors]

📌 Commit d3d8a40 has been approved by tgross35

It is now in the queue for this repository.

[bors]

☔ The latest upstream changes (presumably #146946) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[RalfJung]

@bors r=tgross35

[bors]

📌 Commit f509dff has been approved by tgross35

It is now in the queue for this repository.