clang svn has now a new checker -fsanitize=undefined And it found this problem in blead: ./miniperl -Ilib -Idist/Cwd -Idist/Cwd/lib -Idist/Carp/lib pod/perlmodlib.PL -q regcomp.c:3885:21: fatal error: signed integer overflow: 2 + 2147483647 cannot be represented in type 'int' delta += (minnext + deltanext) * maxcount - minnext * mincount; 2 + I32_MAX (minnext + deltanext) Since introducing a temp. U32 deltatmp to hold minnext + deltanext did not help, we need to change the logic to be safe. U32 deltatmp = (minnext + deltanext) * maxcount; delta += (U32)(deltatmp - minnext * mincount); -- Reini Urban http://cpanel.net/ http://www.perl-compiler.org/