[libc++][test] Mark ranges.transform.pass.cpp UNSUPPORTED for AIX

[jloser]

Summary

The ranges.transform.pass.cpp often times out on CI for AIX (32-bit and 64-bit)
only. Mark the test as UNSUPPORTED for AIX for now. It should be looked into in
the future.

[philnik]

The test is just long. So either the test should be made shorted somehow or the timeout for AIX should be longer. XFAILing it doesn't solve the problem in any way. It's just the 50/50 chance of passing reversed to a 50/50 chance of failing.

[jloser]

In D127051#3558524, @philnik wrote:

The test is just long. So either the test should be made shorted somehow or the timeout for AIX should be longer. XFAILing it doesn't solve the problem in any way. It's just the 50/50 chance of passing reversed to a 50/50 chance of failing.

I see. So, we could bump the timeout set by run-buildbot to bump it up from the current 1200 seconds, but that's awfully high already. Have you already looked into why it's taking so long (and only on AIX?)? Is it spending so much time compiling (can look with -ftime-trace and ClangBuildAnalyzer), or something else?

[philnik]

In D127051#3558538, @jloser wrote:

In D127051#3558524, @philnik wrote:

The test is just long. So either the test should be made shorted somehow or the timeout for AIX should be longer. XFAILing it doesn't solve the problem in any way. It's just the 50/50 chance of passing reversed to a 50/50 chance of failing.

I see. So, we could bump the timeout set by run-buildbot to bump it up from the current 1200 seconds, but that's awfully high already. Have you already looked into why it's taking so long (and only on AIX?)? Is it spending so much time compiling (can look with -ftime-trace and ClangBuildAnalyzer), or something else?

The test always takes a long time to run. On my machine it's 47 seconds. I think the average test takes more like one to two seconds. The problem is that we instantiate the actual test with 7 * 7 * 7 ( = 343) iterator combinations. I don't know why it takes twenty minutes on AIX though. I guess something isn't well optimized in the compiler and that gets multiplied 343 times. That's probably something someone from AIX should look into. @DanielMcIntosh-IBM @SeanP @daltenty

[Mordante]

I would prefer to have the test fixed for AIX. However due to the recent number of false positive CI failures I don't mind to disable it temporary on one platform.

libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/ranges.transform.pass.cpp

11

This won't work, now the CI will fail when the test finishes within 1200s. Instead use UNSUPPORTED.
Please add a comment why the test is disabled.

[jloser]

Make the test UNSUPPORTED instead of XFAIL

[jloser]

Add comment explaining why it's UNSUPPORTED

[Mordante]

libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/ranges.transform.pass.cpp

11

This fails to build due to the explanation comment being part of the code parsed by lit.
Please move the comment on its own line. While your at it please make it a complete sentence.

[jloser]

Fix the comment

[jloser]

Reword comment based on Mordante's suggestion

[Mordante]

LGTM, but agree with @philnik that the underlying issue should be fixed.
So I leave the final approval to him.

[philnik]

I think this has to be fixed by IBM, so I'm Ok with it for now.

[ldionne]

I don't think we want to do this -- I increased the timeout on our CI bots to try to avoid this issue. I think we should revert this now that I've bumped the timeout duration (hopefully enough to get rid of these spurious failures).

libcxx/test/std/algorithms/alg.modifying.operations/alg.transform/ranges.transform.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
+// On AIX the test takes a long time, leading to frequent CI timeouts.
+// UNSUPPORTED: LIBCXX-AIX-FIXME
 
 // <algorithm>
 
 // template<input_iterator I, sentinel_for<I> S, weakly_incrementable O,
 //          copy_constructible F, class Proj = identity>
 //   requires indirectly_writable<O, indirect_result_t<F&, projected<I, Proj>>>
 //   constexpr ranges::unary_transform_result<I, O>
 //     ranges::transform(I first1, S last1, O result, F op, Proj proj = {});