gcc 2.3.3's combine.c and BYTE_LOADS_SIGN_EXTEND

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1 total messages Started by Holger Teutsch Thu, 07 Jan 1993 17:50

#1602

Author: Holger Teutsch
Date: Thu, 07 Jan 1993 17:50

46 lines
2484 bytes

Im currently working on a port of gcc 2.3.3 to Intergraph's clipper
processor. This processors uses BYTE_LOADS_SIGN_EXTEND.
Combine.c replaces 'subregs' by 'zero_extend' for BYTE_LOADS_ZERO_EXTEND.
I think 'parallel' code for BYTE_LOADS_SIGN_EXTEND must be added to combine.c.


#ifdef BYTE_LOADS_ZERO_EXTEND
      /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with
	 M wider than N, this would require a paradoxical subreg.
	 Replace the subreg with a zero_extend to avoid the reload that
	 would otherwise be required. */
      if (GET_CODE (SET_SRC (x)) == SUBREG
	  && subreg_lowpart_p (SET_SRC (x))
	  && SUBREG_WORD (SET_SRC (x)) == 0
	  && (GET_MODE_SIZE (GET_MODE (SET_SRC (x)))
	      > GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_SRC (x)))))
	  && GET_CODE (SUBREG_REG (SET_SRC (x))) == MEM)
	SUBST (SET_SRC (x), gen_rtx_combine (ZERO_EXTEND,
					     GET_MODE (SET_SRC (x)),
					     XEXP (SET_SRC (x), 0)));
#endif

/*** added by me ***/
#ifdef BYTE_LOADS_SIGN_EXTEND
      /* If we have (set FOO (subreg:M (mem:N BAR) 0)) with
	 M wider than N, this would require a paradoxical subreg.
	 Replace the subreg with a sign_extend to avoid the reload that
	 would otherwise be required. */
      if (GET_CODE (SET_SRC (x)) == SUBREG
	  && subreg_lowpart_p (SET_SRC (x))
	  && SUBREG_WORD (SET_SRC (x)) == 0
	  && (GET_MODE_SIZE (GET_MODE (SET_SRC (x)))
	      > GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_SRC (x)))))
	  && GET_CODE (SUBREG_REG (SET_SRC (x))) == MEM)
	SUBST (SET_SRC (x), gen_rtx_combine (SIGN_EXTEND,
					     GET_MODE (SET_SRC (x)),
					     XEXP (SET_SRC (x), 0)));
#endif

- Holger

--------------------------------------------------------------------------------
Holger Teutsch, Degussa AG, Abt. IW-AC, Weissfrauenstr.9, D-6000 Frankfurt 11

Tel: +4969218-2316                E-Mail       : teutsch@ffm-iw.Degussa.DE
Fax:         -2616                VMS PSI-Mail : 4569002366::TEUTSCH

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