flow patch for g++ bug

[Jim Wilson]

I checked in this patch today.  This was reviewed by Jeff Law.  This fixes
two problems.

1) The basic block partition code in find_basic_blocks does not match the
   equivalent code in find_basic_blocks_1.
2) The code in find_basic_blocks_1 for handling libcalls does not work if
   the REG_RETVAL note is on the CALL_INSN instead of on the following insn.
   This can happen if these flow routines are called after combine.

Mon Sep 14 20:14:34 1998  Jim Wilson  <wilson@cygnus.com>

	* flow.c (find_basic_blocks): Delete check for in_libcall_block when
	prev_code is a CALL_INSN.  Change check for REG_RETVAL note to
	use in_libcall_block.
	(find_basic_blocks_1): Delete check for in_libcall_block when prev_code
	is a CALL_INSN.  If CALL_INSN and in_libcall_block, then change code
	to INSN.

Index: flow.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gcc/flow.c,v
retrieving revision 1.132
diff -p -r1.132 flow.c
*** flow.c	1998/08/21 07:29:37	1.132
--- flow.c	1998/09/15 03:13:59
*************** find_basic_blocks (f, nregs, file, live_
*** 332,343 ****
  	    || (GET_RTX_CLASS (code) == 'i'
  		&& (prev_code == JUMP_INSN
  		    || (prev_code == CALL_INSN
! 			&& (nonlocal_label_list != 0 || eh_region)
! 			&& ! in_libcall_block)
  		    || prev_code == BARRIER)))
  	  i++;
  
! 	if (code == CALL_INSN && find_reg_note (insn, REG_RETVAL, NULL_RTX))
  	  code = INSN;
  
  	if (code != NOTE)
--- 332,344 ----
  	    || (GET_RTX_CLASS (code) == 'i'
  		&& (prev_code == JUMP_INSN
  		    || (prev_code == CALL_INSN
! 			&& (nonlocal_label_list != 0 || eh_region))
  		    || prev_code == BARRIER)))
  	  i++;
  
! 	/* We change the code of the CALL_INSN, so that it won't start a
! 	   new block.  */
! 	if (code == CALL_INSN && in_libcall_block)
  	  code = INSN;
  
  	if (code != NOTE)
*************** find_basic_blocks_1 (f, nonlocal_label_l
*** 457,464 ****
  	       || (GET_RTX_CLASS (code) == 'i'
  		   && (prev_code == JUMP_INSN
  		       || (prev_code == CALL_INSN
! 			   && (nonlocal_label_list != 0 || eh_note)
! 			   && ! in_libcall_block)
  		       || prev_code == BARRIER)))
  	{
  	  basic_block_head[++i] = insn;
--- 458,464 ----
  	       || (GET_RTX_CLASS (code) == 'i'
  		   && (prev_code == JUMP_INSN
  		       || (prev_code == CALL_INSN
! 			   && (nonlocal_label_list != 0 || eh_note))
  		       || prev_code == BARRIER)))
  	{
  	  basic_block_head[++i] = insn;
*************** find_basic_blocks_1 (f, nonlocal_label_l
*** 518,523 ****
--- 518,528 ----
  	active_eh_region[INSN_UID (insn)] = 
                                          NOTE_BLOCK_NUMBER (XEXP (eh_note, 0));
        BLOCK_NUM (insn) = i;
+ 
+       /* We change the code of the CALL_INSN, so that it won't start a
+ 	 new block.  */
+       if (code == CALL_INSN && in_libcall_block)
+ 	code = INSN;
  
        if (code != NOTE)
  	prev_code = code;