[PATCH] cse (canon_reg): Don't modify insns without using validate_change

[Andreas Krebbel]

Hi,

> In your previous mail you mentioned the need to call apply_change_group 
> after canon_reg; I see places in cse.c where that isn't done.  Why don't
> we need to change them?
The cases I was concerned about where cases where either INSN is NULL_RTX 
or apply_change_group is called later on. According to the comment above 
canon_reg the function must not call validate_change if INSN isn't set.
That's why I've left the check for INSN != 0 in validate_canon_reg. It
should be ok with this.

> Also, the comment at the top of canon_reg seems out of date with this 
> change.
Ok, comment adjusted.

2006-05-30  Andreas Krebbel  <krebbel1@de.ibm.com>

	* cse.c (validate_canon_reg, cse_insn): Don't change insns without
	calling recog.


Index: gcc/cse.c
===================================================================
*** gcc/cse.c.orig	2006-05-29 15:28:11.000000000 +0200
--- gcc/cse.c	2006-05-30 14:04:58.000000000 +0200
*************** static void
*** 2728,2744 ****
  validate_canon_reg (rtx *xloc, rtx insn)
  {
    rtx new = canon_reg (*xloc, insn);
-   int insn_code;
  
    /* If replacing pseudo with hard reg or vice versa, ensure the
       insn remains valid.  Likewise if the insn has MATCH_DUPs.  */
!   if (insn != 0 && new != 0
!       && REG_P (new) && REG_P (*xloc)
!       && (((REGNO (new) < FIRST_PSEUDO_REGISTER)
! 	   != (REGNO (*xloc) < FIRST_PSEUDO_REGISTER))
! 	  || GET_MODE (new) != GET_MODE (*xloc)
! 	  || (insn_code = recog_memoized (insn)) < 0
! 	  || insn_data[insn_code].n_dups > 0))
      validate_change (insn, xloc, new, 1);
    else
      *xloc = new;
--- 2728,2737 ----
  validate_canon_reg (rtx *xloc, rtx insn)
  {
    rtx new = canon_reg (*xloc, insn);
  
    /* If replacing pseudo with hard reg or vice versa, ensure the
       insn remains valid.  Likewise if the insn has MATCH_DUPs.  */
!   if (insn != 0 && new != 0)
      validate_change (insn, xloc, new, 1);
    else
      *xloc = new;
*************** validate_canon_reg (rtx *xloc, rtx insn)
*** 2748,2755 ****
     replace each register reference inside it
     with the "oldest" equivalent register.
  
!    If INSN is nonzero and we are replacing a pseudo with a hard register
!    or vice versa, validate_change is used to ensure that INSN remains valid
     after we make our substitution.  The calls are made with IN_GROUP nonzero
     so apply_change_group must be called upon the outermost return from this
     function (unless INSN is zero).  The result of apply_change_group can
--- 2741,2747 ----
     replace each register reference inside it
     with the "oldest" equivalent register.
  
!    If INSN is nonzero validate_change is used to ensure that INSN remains valid
     after we make our substitution.  The calls are made with IN_GROUP nonzero
     so apply_change_group must be called upon the outermost return from this
     function (unless INSN is zero).  The result of apply_change_group can
*************** cse_insn (rtx insn, rtx libcall_insn)
*** 4943,4959 ****
        rtx dest = SET_DEST (sets[i].rtl);
        rtx src = SET_SRC (sets[i].rtl);
        rtx new = canon_reg (src, insn);
-       int insn_code;
  
        sets[i].orig_src = src;
!       if ((REG_P (new) && REG_P (src)
! 	   && ((REGNO (new) < FIRST_PSEUDO_REGISTER)
! 	       != (REGNO (src) < FIRST_PSEUDO_REGISTER)))
! 	  || (insn_code = recog_memoized (insn)) < 0
! 	  || insn_data[insn_code].n_dups > 0)
! 	validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
!       else
! 	SET_SRC (sets[i].rtl) = new;
  
        if (GET_CODE (dest) == ZERO_EXTRACT)
  	{
--- 4935,4943 ----
        rtx dest = SET_DEST (sets[i].rtl);
        rtx src = SET_SRC (sets[i].rtl);
        rtx new = canon_reg (src, insn);
  
        sets[i].orig_src = src;
!       validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
  
        if (GET_CODE (dest) == ZERO_EXTRACT)
  	{