Re: INSN_SCOPE changes break mips-elf

[Jan Hubicka <jh at suse dot cz>]

> 
> mips-elf has had regressions ever since the INSN_SCOPE changes were installed
> into the tree.  While the number of regressions has gone down since the
> introduction of the INSN_SCOPE changes one regression still remains.
> 
> The remaining regression is gcc.dg/debug/debug-6 where we manage to lose
> all debug information for "xyzzy".  I believe the fundamental problem is your
> code in scope_to_insns_initialize does not properly handle SEQUENCEs as
> generated by the delay slot filling pass.

Hi, this patch makes the note re-emitting pass to walk into sequences
and combine scope of all of them.  I've made the function combine_scopes
global since I want to make combine/peepholer/ifcvt to use it as well
any time sequence of instructions is replaced by another sequence.
This is left for separate patch.

Unfortunately I can not bootstrap any of machine having dealy slots at
the moment so I can't verify the patch properly.  Perhaps later, when it
will be less hot and laboratory re-opened, but I am leaving in 2,5 days.
I've verified that it works on the testcases and that the xyzzy appears
on result at -O2 compilation.

Honza

Thu Jun 20 17:43:58 CEST 2002  Jan Hubicka  <jh@suse.cz>
	* rtl.h (combine_scopes): Declare.
	* cfglayout.c (combine_scopes): New.
	(scope_to_insns_finalize): Use combine_scopes for sequences.

Index: rtl.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/rtl.h,v
retrieving revision 1.362
diff -c -3 -p -r1.362 rtl.h
*** rtl.h	14 Jun 2002 18:57:36 -0000	1.362
--- rtl.h	20 Jun 2002 15:42:50 -0000
*************** extern rtx next_label			PARAMS ((rtx));
*** 1414,1419 ****
--- 1414,1422 ----
  extern rtx next_cc0_user		PARAMS ((rtx));
  extern rtx prev_cc0_setter		PARAMS ((rtx));
  
+ /* In cfglayout.c  */
+ extern tree combine_scopes		PARAMS ((tree, tree));
+ 
  /* In jump.c */
  extern rtx next_nondeleted_insn		PARAMS ((rtx));
  extern enum rtx_code reverse_condition	PARAMS ((enum rtx_code));
Index: cfglayout.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/cfglayout.c,v
retrieving revision 1.19
diff -c -3 -p -r1.19 cfglayout.c
*** cfglayout.c	4 Jun 2002 17:32:50 -0000	1.19
--- cfglayout.c	20 Jun 2002 15:42:50 -0000
*************** set_block_levels (block, level)
*** 259,264 ****
--- 259,278 ----
      }
  }
  
+ /* Return sope resulting from combination of S1 and S2.  */
+ tree
+ combine_scopes (s1, s2)
+      tree s1, s2;
+ {
+    if (!s1)
+      return s2;
+    if (!s2)
+      return s1;
+    if (BLOCK_NUMBER (s1) > BLOCK_NUMBER (s2))
+      return s1;
+    return s2;
+ }
+ 
  /* Emit lexical block notes needed to change scope from S1 to S2.  */
  
  static void
*************** scope_to_insns_finalize ()
*** 327,332 ****
--- 341,358 ----
        tree this_block;
  
        this_block = INSN_SCOPE (insn);
+       /* For sequences compute scope resulting from merging all scopes
+          of instructions nested inside. */
+       if (GET_CODE (PATTERN (insn)) == SEQUENCE)
+ 	{
+ 	  int i;
+ 	  rtx body = PATTERN (insn);
+ 
+ 	  this_block = NULL;
+ 	  for (i = 0; i < XVECLEN (body, 0); i++)
+ 	    this_block = combine_scopes (this_block,
+ 			    		 INSN_SCOPE (XVECEXP (body, 0, i)));
+ 	}
        if (! this_block)
  	continue;