[Bug tree-optimization/69039] New: segfault with ftree-parallelize-loops=2

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69039

            Bug ID: 69039
           Summary: segfault with ftree-parallelize-loops=2
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

Bootstrap with -ftree-parallelize-loops=2 by default (see PR68967) breaks here:
...
$ g++ ira-color.c -O2 -S -w -ftree-parallelize-loops=2
ira-color.c: In function void ira_color()�:
ira-color.c:113120:1: internal compiler error: Segmentation fault
 ira_color (void)
 ^~~~~~~~~

0xd6323f crash_signal
        src/gcc/toplev.c:334
0xefe02b contains_struct_check(tree_node*, tree_node_structure_enum, char
const*, int, char const*)
        src/gcc/tree.h:3110
0xefe02b may_propagate_copy(tree_node*, tree_node*)
        src/gcc/tree-ssa-propagate.c:1396
0xda1200 gimple_merge_blocks
        src/gcc/tree-cfg.c:1868
0x9056d5 merge_blocks(basic_block_def*, basic_block_def*)
        src/gcc/cfghooks.c:774
0xdaa854 cleanup_tree_cfg_bb
        src/gcc/tree-cfgcleanup.c:646
0xdab20c cleanup_tree_cfg_1
        src/gcc/tree-cfgcleanup.c:712
0xdab20c cleanup_tree_cfg_noloop
        src/gcc/tree-cfgcleanup.c:747
0xdab20c cleanup_tree_cfg()
        src/gcc/tree-cfgcleanup.c:798
0xc1c1e1 execute_expand_omp
        src/gcc/omp-low.c:13384
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