Patch to fix gcse multiple set handling

[John Wehle]

This patch allows an ARM cross compiler to be built.  Previously
an INSN containing multiple sets would be recorded and cause
an abort later on in pre_delete.  This patch passes make bootstrap
and check on i386-unknown-freebsd4.2.  It also passes make check
for powerpc-eabisim.

ChangeLog:

Sat Mar 10 00:46:32 EST 2001  John Wehle  (john@feith.com)

	* gcse.c (hash_scan_insn): Update comments.
	Don't record multiple sets.

Enjoy!

-- John Wehle
------------------8<------------------------8<------------------------
*** gcc/gcse.c.ORIGINAL	Thu Mar  1 23:57:34 2001
--- gcc/gcse.c	Sat Mar 10 00:34:36 2001
*************** hash_scan_call (x, insn)
*** 2014,2023 ****
  
     Only available expressions that set a single pseudo-reg are recorded.
  
-    Single sets in a PARALLEL could be handled, but it's an extra complication
-    that isn't dealt with right now.  The trick is handling the CLOBBERs that
-    are also in the PARALLEL.  Later.
- 
     If SET_P is non-zero, this is for the assignment hash table,
     otherwise it is for the expression hash table.
     If IN_LIBCALL_BLOCK nonzero, we are in a libcall block, and should
--- 2014,2019 ----
*************** hash_scan_insn (insn, set_p, in_libcall_
*** 2041,2057 ****
    if (GET_CODE (pat) == SET)
      hash_scan_set (pat, insn, set_p);
    else if (GET_CODE (pat) == PARALLEL)
!     for (i = 0; i < XVECLEN (pat, 0); i++)
!       {
! 	rtx x = XVECEXP (pat, 0, i);
! 
! 	if (GET_CODE (x) == SET)
! 	  hash_scan_set (x, insn, set_p);
! 	else if (GET_CODE (x) == CLOBBER)
! 	  hash_scan_clobber (x, insn);
! 	else if (GET_CODE (x) == CALL)
! 	  hash_scan_call (x, insn);
!       }
  
    else if (GET_CODE (pat) == CLOBBER)
      hash_scan_clobber (pat, insn);
--- 2037,2058 ----
    if (GET_CODE (pat) == SET)
      hash_scan_set (pat, insn, set_p);
    else if (GET_CODE (pat) == PARALLEL)
!     {
!       rtx set = single_set (insn);
! 
!       if (set)
! 	hash_scan_set (set, insn, set_p);
! 
!       for (i = 0; i < XVECLEN (pat, 0); i++)
! 	{
! 	  rtx x = XVECEXP (pat, 0, i);
! 
! 	  if (GET_CODE (x) == CLOBBER)
! 	    hash_scan_clobber (x, insn);
! 	  else if (GET_CODE (x) == CALL)
! 	    hash_scan_call (x, insn);
! 	}
!     }
  
    else if (GET_CODE (pat) == CLOBBER)
      hash_scan_clobber (pat, insn);
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|    John Wehle    |     Fax: 1-215-540-5495  |                         |
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