[Bug rtl-optimization/94148] New: The DF framework uses bb->aux, which is for passes only

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94148

            Bug ID: 94148
           Summary: The DF framework uses bb->aux, which is for passes
                    only
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: segher at gcc dot gnu.org
  Target Milestone: ---

df-core.c:df_worklist_dataflow_doublequeue uses bb->aux, clobbering it,
while that field is documented as

  /* Auxiliary info specific to a pass.  */
  PTR GTY ((skip (""))) aux;

and some passes that do use DF also use bb->aux.  This gives problems
with overlapping lifetimes.


This blocks fixing PR94042 properly.