[Bug rtl-optimization/66420] valgrind error in improve_allocation

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66420

--- Comment #6 from David Binderman <dcb314 at hotmail dot com> ---

More detail:

==11707== Conditional jump or move depends on uninitialised value(s)
==11707==    at 0x8C3209: improve_allocation() (ira-color.c:2878)
==11707==    by 0x8C734C: color_allocnos (ira-color.c:3201)
==11707==    by 0x8C734C: color_pass(ira_loop_tree_node*) (ira-color.c:3310)
==11707==    by 0x8B07D6: ira_traverse_loop_tree(bool, ira_loop_tree_node*,
void (*)(ira_loop_tree_node*), void (*)(ira_loop_tree_node*))
(ira-build.c:1781)
==11707==    by 0x8C0E02: do_coloring (ira-color.c:3461)

Merely -O2 will cause the problem. -O3 -march=native not required.