On Sat, 15 Jul 2017, Yuri Gribov wrote: > Hi, > > This is a follow-up on https://gcc.gnu.org/ml/gcc/2017-07/msg00078.html > > compare_assert_loc in tree-vrp.c could return unpredictable results > due to implicit conversion of unsigned subtraction to int here: > return ha - hb; > > This could return inconsistent results for objects with the following hashes: > a: 0xdc8e4f72U > b: 0x912ab538U > c: 0x5ae66e3bU > Then > a > b because (int)(0xdc8e4f72U - 0x912ab538U) > 0 > b > c because (int)(0x912ab538U - 0x5ae66e3bU) > 0 > but > a < c because (int)(0xdc8e4f72U - 0x5ae66e3bU) == (int)0x81a7e137U < 0 > > Bug was found with https://github.com/yugr/sortcheck > > Bootstrapped and regtested in x64, ok for trunk?
Ok. Thanks, Richard.
