[Bug tree-optimization/69039] [6 regression] segfault with ftree-parallelize-loops=2

[vries at gcc dot gnu.org]

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

--- Comment #7 from vries at gcc dot gnu.org ---
(In reply to vries from comment #6)
> Created attachment 37132 [details]
> tentative patch

The tentative patch fixes the reduced test-case, but we run into another ICE
with the full test-case:
...
ira-color.c: In function ‘<built-in>’:
ira-color.c:110833:8: error: invalid PHI argument
      r < conflict_hregno + conflict_nregs;
        ^

&conflicting_regs
ira-color.c:110833:8: error: location references block not in block tree
&conflicting_regs
prephitmp_59 = PHI <_60(22), &conflicting_regs(11)>
ira-color.c:110833:8: internal compiler error: verify_gimple failed
0x11b7aca verify_gimple_in_cfg(function*, bool)
        src/gcc/tree-cfg.c:5119
0xf9c3d2 execute_function_todo
        src/gcc/passes.c:1958
0xf9b4a5 do_per_function
        src/gcc/passes.c:1645
0xf9c5ae execute_todo
        src/gcc/passes.c:2010
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
...