[Bug rtl-optimization/32790] New: REG_N_SETS holds wrong value

["georgjohann at web dot de" <gcc-bugzilla@gcc.gnu.org>]

In ./gcc/regclass.c:reg_scan_mark_refs()

there is this source code:

    case SET:
      /* Count a set of the destination if it is a register.  */
      for (dest = SET_DEST (x);
           GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
           || GET_CODE (dest) == ZERO_EXTEND;
           dest = XEXP (dest, 0))
        ;

This code counts the number of times a REG is changed (eventually used in
combine, reload, regrenumber, ...)

IMHO, the ZERO_EXTEND is a typo and should be a ZERO_EXTRACT, because (set
(zero_extract (reg foo bar)) are RTX that are actually generated in some
define_insn/define_expand insv (provided HAVE_insv) if the source deals with
bitfields.

As this code can already be seen in GCC 3.3.*, I guess this is not very
critical. But it leads to problems in a non-standard target (tricore) that uses
the information in REG_N_SETS().

Greets,

Georg-Johann Lay
georg.lay@hightec-rt.com


-- 
           Summary: REG_N_SETS holds wrong value
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: georgjohann at web dot de
 GCC build triplet: any
  GCC host triplet: any
GCC target triplet: any


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32790