[Bug c++/65613] New: valgrind error in find_call_crossed_cheap_reg

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65613

            Bug ID: 65613
           Summary: valgrind error in find_call_crossed_cheap_reg
           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 35167
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35167&action=edit
C++ source code

The attached code, when compiled by gcc trunk dated 20150325
under valgrind, and flags -O3 -march=native, does this

==28822== Use of uninitialised value of size 8
==28822==    at 0xBDB4FC: find_call_crossed_cheap_reg (ira-lives.c:1037)
==28822==    by 0xBDB4FC: process_bb_node_lives(ira_loop_tree_node*)
(ira-lives.c:1218)
==28822==    by 0xBB917E: ira_traverse_loop_tree(bool, ira_loop_tree_node*,
void (*)(ira_loop_tree_node*), void (*)(ira_loop_tree_node*))
(ira-build.c:1845)
==28822==    by 0xBDBA41: ira_create_allocno_live_ranges() (ira-lives.c:1582)
==28822==    by 0xBBB0BB: ira_build() (ira-build.c:3461)
==28822==    by 0xBB1550: ira (ira.c:5254)

ira-lives.c:1037 is

         if (!REG_P (dest) || HARD_REGISTER_P (dest)