https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66420
--- Comment #1 from David Binderman <dcb314 at hotmail dot com> --- Still seems to be happening with gcc trunk dated as follows Last Changed Rev: 230563 Last Changed Date: 2015-11-18 19:45:47 +0000 (Wed, 18 Nov 2015) ==12746== Conditional jump or move depends on uninitialised value(s) ==12746== at 0x90095F: improve_allocation() (in /home/dcb/gcc/working/gcc/cc1) ==12746== by 0x905623: color_pass(ira_loop_tree_node*) (in /home/dcb/gcc/working/gcc/cc1) ==12746== by 0x8E4216: ira_traverse_loop_tree(bool, ira_loop_tree_node*, void (*)(ira_loop_tree_node*), void (*)(ira_loop_tree_node*)) (in /home/dcb/gcc/working/gcc/cc1) ==12746== by 0x8FCC1C: ira_color() (in /home/dcb/gcc/working/gcc/cc1)