[Bug target/68770] New: [6 Regression] Conditional jump or move depends on uninitialised value(s) default_secondary_reload() targhooks.c:940

["trippels at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68770

            Bug ID: 68770
           Summary: [6 Regression]  Conditional jump or move depends on
                    uninitialised value(s) default_secondary_reload()
                    targhooks.c:940
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
  Target Milestone: ---
              Host: powerpc64-unknown-linux-gnu
            Target: powerpc64-unknown-linux-gnu
             Build: powerpc64-unknown-linux-gnu

checking=valgrind shows:

==115918== Conditional jump or move depends on uninitialised value(s)
==115918==    at 0x107D29F4: default_secondary_reload(bool, rtx_def*, int,
machine_mode, secondary_reload_info*) (targhooks.c:940)
==115918==    by 0x10AD9B93: rs6000_secondary_reload(bool, rtx_def*, int,
machine_mode, secondary_reload_info*) (rs6000.c:18414)
==115918==    by 0x105FBCB7: copy_cost(rtx_def*, machine_mode, int, bool,
secondary_reload_info*) [clone .part.7] (ira-costs.c:445)
==115918==    by 0x105FBD27: copy_cost (ira-costs.c:434)
==115918==    by 0x105FBD27: copy_cost(rtx_def*, machine_mode, int, bool,
secondary_reload_info*) [clone .part.7] (ira-costs.c:452)
==115918==    by 0x105FC243: copy_cost (ira-costs.c:434)
==115918==    by 0x105FC243: record_reg_classes(int, int, rtx_def**,
machine_mode*, char const**, rtx_insn*, reg_class*) [clone .constprop.42]
(ira-costs.c:984)
==115918==    by 0x105FE11F: record_operand_costs(rtx_insn*, reg_class*)
(ira-costs.c:1325)
==115918==    by 0x105FE657: scan_one_insn (ira-costs.c:1462)
==115918==    by 0x105FE657: process_bb_for_costs(basic_block_def*)
(ira-costs.c:1583)
==115918==    by 0x105F488F: ira_traverse_loop_tree(bool, ira_loop_tree_node*,
void (*)(ira_loop_tree_node*), void (*)(ira_loop_tree_node*))
(ira-build.c:1798)
==115918==    by 0x10600E3B: find_costs_and_classes(_IO_FILE*)
(ira-costs.c:1680)
==115918==    by 0x1060160F: ira_costs() (ira-costs.c:2213)
==115918==    by 0x105F9F0F: ira_build() (ira-build.c:3419)
==115918==    by 0x105EDE03: ira (ira.c:5219)
==115918==    by 0x105EDE03: (anonymous
namespace)::pass_ira::execute(function*) (ira.c:5511)
==115918==