cselib_record_set breaks due to auto_inc_dec

[Paulo Matos]

Hi,

After pro and epilogue pass I have the following epilogue insn:
(insn/f 20 19 21 2 (parallel [
            (set (mem:DI (plus:SI (reg:SI 26 r26)
                        (reg/f:SI 57 r57)) [0 S8 A8])
                (reg:DI 57 r57))
            (set (reg/f:SI 57 r57)
                (plus:SI (reg:SI 26 r26)
                    (reg/f:SI 57 r57)))
        ]) bdra_main.i:2 -1
     (expr_list:REG_DEAD (reg:SI 26 r26)
        (expr_list:REG_FRAME_RELATED_EXPR (set (mem:DI (pre_modify:SI (reg/f:SI 
57 r57)
                        (plus:SI (reg/f:SI 57 r57)
                            (const_int -8208 [0xffffffffffffdff0]))) [0 S8 A8])
                (reg:DI 57 r57))
            (nil))))

During cselib_record_sets, 2 sets are recognized (the ones in the parallel) and 
then a third one is added by cselib_record_autoinc_cb:
(set (reg:SI 57) (plus (reg:SI 57) (const_int -8208)))

After for_each_inc_dec calling cselib_record_autoinc_cb sets array is:
sets[0]:
  dest: (reg/f:SI 57 r57)
  src: (plus:SI (reg:SI 26 r26)
                    (reg/f:SI 57 r57))
sets[1]:
  dest: (mem:DI (plus:SI (reg:SI 26 r26)
                        (reg/f:SI 57 r57)))
  src: (reg:DI 57 r57)
sets[2]:
  dest: (reg/f:SI 57 r57)  
  src: (plus:SI (reg/f:SI 57 r57)
                            (const_int -8208 [0xffffffffffffdff0]))))

The last loop in cselib_record_sets is:
  for (i = 0; i < n_sets; i++)
    {
      rtx dest = sets[i].dest;
      if (REG_P (dest)
          || (MEM_P (dest) && cselib_record_memory))
        cselib_record_set (dest, sets[i].src_elt, sets[i].dest_addr_elt);
    }

This fails while trying to register the second set to reg:SI 57, in 
          /* The register should have been invalidated.  */
          gcc_assert (REG_VALUES (dreg)->elt == 0);

This seems to be a manifestation of PR32335, where the extra assignment to the 
same register (in this case r57) is added by auto_inc_dec analysis and not 
explicit in the parallel.

Has anyone come across this before?

Paulo Matos