Re: 19991023 segfault compiling XFree86

[Richard Henderson <rth at cygnus dot com>]

On Wed, Oct 27, 1999 at 08:40:00AM +0930, Alan Modra wrote:
> Reading symbols from /usr/lib/gcc-lib/i586-linux/2.96/cc1...done.
> (gdb) info stack
> #0  make_edge (edge_cache=0x0, src=0x826b868, dst=0x0, flags=0)
> at /usr/src/egcs/gcc/flow.c:1110

This fixes it.  I added the case to the testsuite.


r~


        * flow.c (merge_blocks_move_predecessor_nojumps): Cope
        with already adjacent blocks, but no fallthru.
        (merge_blocks_move_successor_nojumps): Simplify.
        (debug_flow_info): New.

Index: flow.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/flow.c,v
retrieving revision 1.174
diff -c -p -d -r1.174 flow.c
*** flow.c	1999/10/20 14:04:01	1.174
--- flow.c	1999/10/27 03:20:06
*************** static int
*** 2011,2022 ****
  merge_blocks_move_predecessor_nojumps (a, b)
       basic_block a, b;
  {
!   rtx start, end, insertpoint, barrier;
    int index;
  
    start = a->head;
    end = a->end;
-   insertpoint = PREV_INSN (b->head);
  
    /* We want to delete the BARRIER after the end of the insns we are
       going to move.  If we don't find a BARRIER, then do nothing.  This
--- 2011,2021 ----
  merge_blocks_move_predecessor_nojumps (a, b)
       basic_block a, b;
  {
!   rtx start, end, barrier;
    int index;
  
    start = a->head;
    end = a->end;
  
    /* We want to delete the BARRIER after the end of the insns we are
       going to move.  If we don't find a BARRIER, then do nothing.  This
*************** merge_blocks_move_predecessor_nojumps (a
*** 2042,2048 ****
    start = squeeze_notes (start, end);
  
    /* Scramble the insn chain.  */
!   reorder_insns (start, end, insertpoint);
  
    if (rtl_dump_file)
      {
--- 2041,2048 ----
    start = squeeze_notes (start, end);
  
    /* Scramble the insn chain.  */
!   if (end != PREV_INSN (b->head))
!     reorder_insns (start, end, PREV_INSN (b->head));
  
    if (rtl_dump_file)
      {
*************** static int
*** 2073,2083 ****
  merge_blocks_move_successor_nojumps (a, b)
       basic_block a, b;
  {
!   rtx start, end, insertpoint, barrier;
  
    start = b->head;
    end = b->end;
-   insertpoint = a->end;
  
    /* We want to delete the BARRIER after the end of the insns we are
       going to move.  If we don't find a BARRIER, then do nothing.  This
--- 2073,2082 ----
  merge_blocks_move_successor_nojumps (a, b)
       basic_block a, b;
  {
!   rtx start, end, barrier;
  
    start = b->head;
    end = b->end;
  
    /* We want to delete the BARRIER after the end of the insns we are
       going to move.  If we don't find a BARRIER, then do nothing.  This
*************** merge_blocks_move_successor_nojumps (a, 
*** 2103,2109 ****
    start = squeeze_notes (start, end);
  
    /* Scramble the insn chain.  */
!   reorder_insns (start, end, insertpoint);
  
    /* Now blocks A and B are contiguous.  Merge them.  */
    merge_blocks_nomove (a, b);
--- 2102,2108 ----
    start = squeeze_notes (start, end);
  
    /* Scramble the insn chain.  */
!   reorder_insns (start, end, a->end);
  
    /* Now blocks A and B are contiguous.  Merge them.  */
    merge_blocks_nomove (a, b);
*************** dump_flow_info (file)
*** 4964,4969 ****
--- 4963,4974 ----
      }
  
    putc('\n', file);
+ }
+ 
+ void
+ debug_flow_info ()
+ {
+   dump_flow_info (stderr);
  }
  
  static void