[Bug c++/65617] New: new valgrind error in update_costs_from_copies

["dcb314 at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65617

            Bug ID: 65617
           Summary: new valgrind error in update_costs_from_copies
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com

Created attachment 35170
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35170&action=edit
C++ source code

Given the source code from #47903, there is a new valgrind error in
update_costs_from_copies.

$ diff 20150323.out 20150329.out
> ==13155== Conditional jump or move depends on uninitialised value(s)
> ==13155==    at 0xBDF10D: update_costs_from_copies(ira_allocno*, bool, bool) [
clone .constprop.58] (ira-color.c:1445)
> ==13155==    by 0xBE12B9: assign_hard_reg(ira_allocno*, bool) [clone .constpro
p.55] (ira-color.c:1896)
> ==13155==    by 0xBEA536: pop_allocnos_from_stack (ira-color.c:2589)
> ==13155==    by 0xBEA536: color_allocnos (ira-color.c:3095)

This new error appeared sometime >= 20150323.

ira-color.c:1445 is

  ira_assert (hard_regno >= 0 && ALLOCNO_CLASS (allocno) != NO_REGS);