[Bug c++/90408] New: >= -O2 suddenly generates code

[oliverst at online dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90408

            Bug ID: 90408
           Summary: >= -O2 suddenly generates code
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: oliverst at online dot de
  Target Milestone: ---

Created attachment 46324
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46324&action=edit
example code

The attached code should produce an empty main(), but does produce code with
optimizations >= -O2. It appears to be related to the switch-case.

-std=c++11 -O1
no code generated

-std=c++11 -O2
code generated in GCC 5.5.0 and GCC >= 7.1

Also using -Os produces more code than -O1.