I hit a bug while compiling Gnu Emacs trunk development. The following test : passed 17/1152 bool-vector-count-population-1-nil fails unless I apply the following patch : === modified file 'src/data.c' --- src/data.c 2014-01-03 06:47:27 +0000 +++ src/data.c 2014-01-24 14:59:16 +0000 @@ -3012,8 +3012,10 @@ { int i = 0, count = 0; while (count += count_one_bits_ll (w), - BITS_PER_BITS_WORD <= (i += BITS_PER_ULL)) + BITS_PER_BITS_WORD <= i) { + i += BITS_PER_ULL; w = shift_right_ull (w); + } return count; } } This is with : $ gcc --version gcc.exe (Rev6, Built by MSYS2 project) 4.8.2 Copyright (C) 2013 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Given the nature of the patch, I don't think it is specific of th MinGW64 gcc version. Regards, Fabrice Popineau