https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69937
Bug ID: 69937 Summary: -Wuninitialized does not warn when an uninitialised variable is printed before use Product: gcc Version: 5.3.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: kloedej at knmi dot nl Target Milestone: --- Created attachment 37778 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37778&action=edit minimal example that shows the bug The attached example code first prints an uninitialised variable, then uses it in an assignment, but no warning if issued for the first subroutine if the code is compiled with: gfortran -Wuninitialized -c warning_test.f90 on the other hand if the order is reversed (as in the second subroutine), and the assignment comes before the write statement, a warning is issued. This may be related to issue #34721 Software version used for testing: GNU Fortran (GCC) 5.3.1 20151207 (Red Hat 5.3.1-2) running on Fedora 23. Output of the compile command: >gfortran -Wuninitialized -c warning_test.f90 warning_test.f90:16:0: b = a ^ Warning: ‘a’ is used uninitialized in this function [-Wuninitialized] >