[Bug c++/66590] New: switch statement: incorrect warning "reaches end of non-void function"

["brutus at free dot fr" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66590

            Bug ID: 66590
           Summary: switch statement: incorrect warning "reaches end of
                    non-void function"
           Product: gcc
           Version: 4.9.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: brutus at free dot fr
  Target Milestone: ---

Created attachment 35803
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35803&action=edit
code snippet generated erroneous "end of non-void function" warning

If the attached code is compiled with -Wall, gcc versions 4.9.2, 5.1 and others
incorrectly warn about reaching end of non-void function.

this is typically reproduced with:
 /opt/install/gcc-4.9.2/bin/g++ -Wall -c switch.cpp


warning disappears if:
  -optimisation is at least -O1
  -OR declaration of ~A() line 1 is removed
  -OR declaration of variable "a" line 6 is removed
  -OR declaration of variable "tmp" line 9 is removed
  -OR break on line 9 is removed