https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78644
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Verified reverting the tree-ssa-ccp.c hunk of r242920 makes the ICE go away (then instead of _18 = _7 + _17; there is _18 = x2_3 + _17; (no idea why _7 hasn't actually been replaced with 0 but just with x2_3, though there is UB involved in the loop if x4[0] isn't 0 at the beginning)).
