https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92717
--- Comment #2 from Markus Dreseler <gnu.org at mrks dot info> --- > Try using __DATE__ macro and you will see it is not :). Can't confirm: # /usr/bin/c++ -D__DATE__=0 -D__TIMESTAMP__=0 -D__TIME__=0 -x c++-header -include test.hxx -o test.hxx.gch -c test.hxx.cxx && md5sum test.hxx.gch produces some new warnings, but again different file hashes. Here are some other options that I have tested but that have no effect: * SOURCE_DATE_EPOCH=0 * -fno-pie * -nodefaultlibs -nostartfiles -nostdlib