The attached testcase has an uninitialized variable, it is not diagnosed with -O2 -W -Wall. Gcc 3.2 says,
uninit.i: In function `bitmap_print_value_set': uninit.i:8: warning: `first' might be used uninitialized in this function this is a regression -- Summary: Missing 'used unintialized' warning Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: nathan at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18501