https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78965
Bug ID: 78965 Summary: [7 Regression] Invalid -fprintf-return-value optimization Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: jakub at gcc dot gnu.org Target Milestone: --- int main () { int a = 5, b = 6; int c = __builtin_snprintf (0, 0, "a%nb%nc", &a, &b); if (a + b + c != 6) __builtin_abort (); return 0; } is miscompiled since r242674 at -O2.