[Bug rtl-optimization/98144] New: REE needs 6GB DF memory when compiling insn-extract.c with RTL checking enabled

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98144

            Bug ID: 98144
           Summary: REE needs 6GB DF memory when compiling insn-extract.c
                    with RTL checking enabled
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

otherwise it doesn't do much with all this DF analysis.

 ree                                :   0.07 (  0%)   0.00 (  0%)   0.05 (  0%)
   75k (  0%)
...
 TOTAL                              :  26.43          5.86         32.32       
 1655M
26.44user 5.91system 0:32.36elapsed 99%CPU (0avgtext+0avgdata
5555408maxresident)k
0inputs+0outputs (0major+2139837minor)pagefaults 0swaps


it does

  /* Construct DU chain to get all reaching definitions of each
     extension instruction.  */
  df_set_flags (DF_RD_PRUNE_DEAD_DEFS);
  df_chain_add_problem (DF_UD_CHAIN + DF_DU_CHAIN);
  df_mir_add_problem ();
  df_analyze ();

and the MIR problem causes it to explode.