TestFwdBackUnsafe hangs on Windows with MSVC VS2017
Description
Steps:
Checkout trunk [r41094].
Build with MSVC (VS2017) for 'x64' and 'Release'.
Run tests with `icucheck.bat x64 Release`.
`cintltest.exe` hangs running the utf8tst function "`TestFwdBackUnsafe`".
Activity
Trac Comment 1 by —2018-03-12T21:43:31.701Z
I can't repro the issue with the "Debug" x64 build, so this seems like another bug in the MSVC optimizer.
We will likely need to disable optimization for a particular function, but at this point I'm not sure which one.
Trac Comment 3 by —2018-03-13T01:33:59.772Z
For more context:
I was running the ICU tests on my Windows PC for Release/x64 (built with MSVC 2017) and the tests hang during the cintltest "TestFwdBackUnsafe" test:
Looking at the Jenkins builds for Windows, it looks like they started failing some time after revision 41075.
(The last successful build was here: https://cldr-build.unicode.org/jenkins/job/icu/job/icu4c/781/ )
However, I don’t really see any changes on trunk related to cintltest and/or utf8 since revision 41075:
http://bugs.icu-project.org/trac/changeset?reponame=&new=41089%40trunk%2Ficu4c&old=41075%40trunk%2Ficu4c
Additionally, the tests all pass when run against the “Debug” build on x64.
The issue also does not occur when building using VS2015 with “Release” builds, so it seems like this is a bug in the MSVC optimizer in VS2017.
It looks like I will need to disable optimization for the particular test function.
