[Bug middle-end/64498] New: [5 Regression] Cannot build Firefox with LTO: ICE in substitute_and_fold_dom_walker::before_dom_children

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64498

            Bug ID: 64498
           Summary: [5 Regression] Cannot build Firefox with LTO: ICE in
                    substitute_and_fold_dom_walker::before_dom_children
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: markus at trippelsdorf dot net

Hello.

With gcc version 5.0.0 20150105 (experimental) (GCC) and latest master branch
of Firefox, compiled with -O2 and -flto, I see following problem in a ltrans:


/home/marxin/Programming/gecko-dev/js/src/builtin/Intl.cpp: In function
âNewUDateFormatâ:
/home/marxin/Programming/gecko-dev/js/src/builtin/Intl.cpp:1840:0: internal
compiler error: Segmentation fault
 NewUDateFormat(JSContext *cx, HandleObject dateTimeFormat)
 ^
0x8de73f crash_signal
    ../../gcc/toplev.c:359
0x98feab gimple_code
    ../../gcc/gimple.h:1545
0x98feab gimple_nop_p
    ../../gcc/gimple.h:5589
0x98feab get_default_value
    ../../gcc/tree-ssa-ccp.c:291
0x98feab get_value
    ../../gcc/tree-ssa-ccp.c:365
0x98feab get_constant_value
    ../../gcc/tree-ssa-ccp.c:384
0xa0556d replace_uses_in
    ../../gcc/tree-ssa-propagate.c:948
0xa0556d substitute_and_fold_dom_walker::before_dom_children(basic_block_def*)
    ../../gcc/tree-ssa-propagate.c:1151
0xdf4022 dom_walker::walk(basic_block_def*)
    ../../gcc/domwalk.c:188
0xa05030 substitute_and_fold(tree_node* (*)(tree_node*), bool
(*)(gimple_stmt_iterator*), bool)
    ../../gcc/tree-ssa-propagate.c:1230
0x990cb0 ccp_finalize
    ../../gcc/tree-ssa-ccp.c:934
0x990cb0 do_ssa_ccp
    ../../gcc/tree-ssa-ccp.c:2374
0x990cb0 execute
    ../../gcc/tree-ssa-ccp.c:2406

Where:

#0  0x0000000000bb4950 in gimple_code (g=0x0) at ../../gcc/gimple.h:1545
#1  0x0000000000bb52cc in gimple_nop_p (g=0x0) at ../../gcc/gimple.h:5589
#2  0x0000000000bb6350 in get_default_value (var=0x7fffe5d24870) at
../../gcc/tree-ssa-ccp.c:291
#3  0x0000000000bb6620 in get_value (var=0x7fffe5d24870) at
../../gcc/tree-ssa-ccp.c:365
#4  0x0000000000bb66b7 in get_constant_value (var=0x7fffe5d24870) at
../../gcc/tree-ssa-ccp.c:384
#5  0x0000000000c48d5e in replace_uses_in (stmt=0x7fffe5d116c0,
get_value=0xbb666e <get_constant_value(tree)>) at
../../gcc/tree-ssa-propagate.c:948
#6  0x0000000000c49484 in substitute_and_fold_dom_walker::before_dom_children
(this=0x7fffffffd430, bb=0x7fffe5d02750) at ../../gcc/tree-ssa-propagate.c:1151
#7  0x000000000108d113 in dom_walker::walk (this=0x7fffffffd430,
bb=0x7fffe5d02750) at ../../gcc/domwalk.c:188
#8  0x0000000000c4975a in substitute_and_fold (get_value_fn=0xbb666e
<get_constant_value(tree)>, fold_fn=0xbbc57c
<ccp_fold_stmt(gimple_stmt_iterator*)>, do_dce=true) at
../../gcc/tree-ssa-propagate.c:1230
#9  0x0000000000bb7c20 in ccp_finalize () at ../../gcc/tree-ssa-ccp.c:934
#10 0x0000000000bbd0a2 in do_ssa_ccp () at ../../gcc/tree-ssa-ccp.c:2374
#11 0x0000000000bbd155 in (anonymous namespace)::pass_ccp::execute
(this=0x1b68c40) at ../../gcc/tree-ssa-ccp.c:2406
#12 0x0000000000a1bbb2 in execute_one_pass (pass=0x1b68c40) at
../../gcc/passes.c:2311
#13 0x0000000000a1bdec in execute_pass_list_1 (pass=0x1b68c40) at
../../gcc/passes.c:2363
#14 0x0000000000a1be1d in execute_pass_list_1 (pass=0x1b67ec0) at
../../gcc/passes.c:2364
#15 0x0000000000a1be5a in execute_pass_list (fn=0x7fffe6a37c78, pass=0x1b67e00)
at ../../gcc/passes.c:2374
#16 0x0000000000745a2c in cgraph_node::expand (this=0x7ffff6a64930) at
../../gcc/cgraphunit.c:1798
#17 0x0000000000745ecb in expand_all_functions () at
../../gcc/cgraphunit.c:1934
#18 0x0000000000746938 in symbol_table::compile (this=0x7ffff6c3a000) at
../../gcc/cgraphunit.c:2284
#19 0x00000000006b154c in lto_main () at ../../gcc/lto/lto.c:3446
#20 0x0000000000ac3b8c in compile_file () at ../../gcc/toplev.c:570
#21 0x0000000000ac5f48 in do_compile () at ../../gcc/toplev.c:2018
#22 0x0000000000ac6152 in toplev::main (this=0x7fffffffd7cf, argc=36,
argv=0x7fffffffd8c8) at ../../gcc/toplev.c:2115
#23 0x000000000067afc9 in main (argc=36, argv=0x7fffffffd8c8) at
../../gcc/main.c:38

in #2:
(gdb) call debug_tree(var)
 <ssa_name 0x7fffe5d24870 nothrowdef_stmt 

    version 578 in-free-list>

in #5:
(gdb) call debug_gimple_stmt(stmt)
# DEBUG code => _578

Unfortunately, problem is in a LTRANS and it's hard to reduce a testcase.
Was there any recent change in CCP? If needed, I can provide dumps.

Thanks,
Martin