[clang] Analysis/analyzeOneFunction.cpp test fails under reverse iteration

[ilovepi]

I typically keep LLVM_REVERSE_ITERATION=On after running into issues on some of the build bots with EXPENSIVE_CHECKS enabled. This morning I noticed that clang/test/Analysis/analyzeOneFunction.cpp started failing.

Its been sometime since I ran clang tests (that I recall), so I'm not sure what revision range is interesting, precisely. I'm guessing anywhere between 912a92a and 4ecb3c7 (I can't imagine I went much more than a month w/o running them at all locally), but I'm not positive.

I about to start trying to bisect, but I'm reporting now incase this is a know/tracked issues or someone will know offhand what's responsible.

[boomanaiden154]

I don't think this is tracked anywhere. My first instinct was to check the reverse-iteration bot (https://lab.llvm.org/buildbot/#/builders/110), but it looks like it was recently offline for many months, and the range it detects for this test is significantly worse (~2 months) than what you have.

[ilovepi]

Bisected to #161666, where this test was introduced. I don't see anything obvious about iteration order, but maybe this kind of operation was always sensitive to iteration order?

Seems like CHECK-DAG: should fix the test failure, though there's probably a more fundamental issue w/ something iterating over the analysis results. #167394 is a potential fix.