https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86137
Bug ID: 86137 Summary: ubsan runtime error in c-format.c Product: gcc Version: 8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: dcb314 at hotmail dot com Target Milestone: --- For this C code, derived from gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-18.c a() { __builtin_sprintf(a, "%9223372036854775808i"); } and a recent ubsan version of gcc trunk, I get $ ~/gcc/results.261388.ubsan/bin/gcc -Wall -c bug445.c ../../trunk/gcc/c-family/c-format.c:1252:20: runtime error: signed integer overflow: 922337203 * 10 cannot be represented in type 'int' Source code is nargnum = 10 * argnum + (*fcp - '0');