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1.53.0 broke ui/consts/const-eval/ub-*.rs tests on s390x (big-endian, 64-bit) (regression) #89577
Description
Probably because s390x is 64-bit big-endian not little-endian, e.g.:
Debian build log, warning several MB
sample
------------------------------------------
diff of 64bit.stderr:
6 |
7 = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
8 = note: the raw bytes of the constant (size: 8, align: 8) {
- 01 00 00 00 00 00 00 00 │ ........
+ 00 00 00 00 00 00 00 01 │ ........
10 }
11
12 error[E0080]: it is undefined behavior to use this value
116 |
117 = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rustc repository if you believe it should not be considered undefined behavior.
118 = note: the raw bytes of the constant (size: 8, align: 4) {
- 78 00 00 00 ff ff ff ff │ x.......
+ 00 00 00 78 ff ff ff ff │ ...x....
120 }
121
122 error[E0080]: it is undefined behavior to use this value
test [ui] ui/consts/const-eval/ub-enum.rs ... FAILED
test [ui] ui/consts/const-eval/ub-int-array.rs ... FAILED
test [ui] ui/consts/const-eval/ub-nonnull.rs ... FAILED
test [ui] ui/consts/const-eval/ub-ref-ptr.rs ... FAILED
test [ui] ui/consts/const-eval/ub-uninhabit.rs ... FAILED
test [ui] ui/consts/const-eval/ub-wide-ptr.rs ... FAILED
These tests were fine in 1.52 so the culprit is probably #76881 @hameerabbasi . I will revert it in Debian for now.
Activity
hameerabbasi commentedon Oct 5, 2021
Thanks for bringing this to my attention! I will attempt to work to fix it on the weekend.
infinity0 commentedon Oct 5, 2021
Great, thanks! We've had similar endianness issues with these tests before; looking through the git history of those test files might give you some more ideas for solutions.
infinity0 commentedon Oct 5, 2021
It looks like #73989 fixed it by replacing an endianness-dependent value 1 with an endianness-independent value 0, not sure if that's suitable for your case...
hameerabbasi commentedon Oct 6, 2021
I had a few similar failures in the PR with different ABIs, I fixed them by limiting the tests to x86-64.
apiraino commentedon Oct 6, 2021
Assigning priority as discussed in the Zulip thread of the Prioritization Working Group.
@rustbot label -I-prioritize +P-medium
hameerabbasi commentedon Oct 11, 2021
I've started a discussion about this on Zulip. Feel free to contribute with ideas?