http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59148
--- Comment #2 from Jack Howarth <howarth at nitro dot med.uc.edu> --- Also confirmed that if you compile the failing test case using current llvm/clang svn with... /sw/opt/llvm-3.4/bin/clang -fsanitize=address -g -fdiagnostics-color=never -O0 -fno-builtin-malloc -fno-builtin-strncpy -lm -m32 -o ./strncpy-overflow-1.exe strncpy-overflow-1.c or /sw/opt/llvm-3.4/bin/clang -fsanitize=address -g -fdiagnostics-color=never -O0 -fno-builtin-malloc -fno-builtin-strncpy -lm -m64 -o ./strncpy-overflow-1.exe strncpy-overflow-1.c that the test case fails as expected.