std float tests: special-case Miri in feature detection

[RalfJung]

Quick work-around to fix miri-test-libstd failures.

r? @tgross35

[tgross35]

This seems reasonable to me, thanks for the fix

@bors r+

[bors]

📌 Commit 302ae8b has been approved by tgross35

It is now in the queue for this repository.

[RalfJung]

@bors r-
Actually, it fails to build...

  0.557143   error[E0425]: cannot find value `TOL_P2` in this scope
  0.000053      --> std/src/f16/tests.rs:613:60
  0.000010       |
  0.000006   613 |     assert_approx_eq!((-5.8f16).to_degrees(), -332.315521, TOL_P2);
  0.000005       |                                                            ^^^^^^ not found in this scope

[RalfJung]

These here use a constant that is gated on reliable_f16, but the test does not have that gate:

rust/library/std/src/f16/tests.rs

Lines 613 to 614 in e18036c

	assert_approx_eq!((-5.8f16).to_degrees(), -332.315521, TOL_P2);
	assert_approx_eq!(pi.to_degrees(), 180.0, TOL_P2);

[tgross35]

Can you change the gates on the constants to allow(unused)?

[RalfJung]

Now it seems to build. :)
@bors r=tgross35

[bors]

📌 Commit 5d96870 has been approved by tgross35

It is now in the queue for this repository.

[tgross35]

Thanks, r=me once CI passes. f128 has the same gate on a constant but I don’t think that one will fail (feel free to make the same change if it does).

[RalfJung]

rust-lang/miri-test-libstd#76 is looking good so the f128 case seems to be fine.

[tgross35]

I assume this is still better to have in-tree rather than always neeing the patch - feel free to cancel if that isn't accurate.

@bors r+

[bors]

💡 This pull request was already approved, no need to approve it again.

• There's another pull request that is currently being tested, blocking this pull request: [bootstrap] Add support for building gcc and libgccjit #125419

[bors]

📌 Commit 5d96870 has been approved by tgross35

It is now in the queue for this repository.

[tgross35]

Oh, I assumed the force push undid the r+ 🤦

[RalfJung]

It did, but I re-approved it. ;)

[tgross35]

Completely missed that, thanks github mobile view :)