[Bug c++/88787] New: [9 regression] C++ constexpr seems to not get expanded

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88787

            Bug ID: 88787
           Summary: [9 regression] C++ constexpr seems to not get expanded
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tnfchris at gcc dot gnu.org
  Target Milestone: ---
            Target: arm-none-linux-gnueabihf

The following testcases from libstdc++ have started failing in the past few
days on trunk:

FAIL: 27_io/filesystem/operations/last_write_time.cc execution test
FAIL: 30_threads/future/cons/constexpr.cc scan-assembler-not
_ZNSt6futureIiEC2Ev
FAIL: 30_threads/future/cons/constexpr.cc scan-assembler-not
_ZNSt6futureIvEC2Ev
FAIL: 30_threads/shared_future/cons/constexpr.cc scan-assembler-not
_ZNSt13shared_futureIiEC2Ev
FAIL: 30_threads/shared_future/cons/constexpr.cc scan-assembler-not
_ZNSt13shared_futureIvEC2Ev

Looking into the tests, it seems that the expression is not evaluated at
compile time as expected anymore but instead are being created dynamically.
e.g. the code contains the inline constructor and destructors and calls to
them.