SOURCES: gcc-pr22071.patch (NEW) - fix ICE in first_vi_for_offset.

[pluto]

Author: pluto                        Date: Fri Jul  1 21:04:30 2005 GMT
Module: SOURCES                       Tag: HEAD
---- Log message:
- fix ICE in first_vi_for_offset.

---- Files affected:
SOURCES:
   gcc-pr22071.patch (NONE -> 1.1)  (NEW)

---- Diffs:

================================================================
Index: SOURCES/gcc-pr22071.patch
diff -u /dev/null SOURCES/gcc-pr22071.patch:1.1
--- /dev/null	Fri Jul  1 23:04:30 2005
+++ SOURCES/gcc-pr22071.patch	Fri Jul  1 23:04:25 2005
@@ -0,0 +1,58 @@
+--- gcc/gcc/tree-ssa-structalias.c	2005/06/30 22:18:35	2.8
++++ gcc/gcc/tree-ssa-structalias.c	2005/07/01 19:45:23	2.9
+@@ -1940,6 +1940,25 @@
+ }
+ 
+ 
++/* Return true if an access to [ACCESSPOS, ACCESSSIZE]
++   overlaps with a field at [FIELDPOS, FIELDSIZE] */
++
++static bool
++offset_overlaps_with_access (const unsigned HOST_WIDE_INT fieldpos,
++			     const unsigned HOST_WIDE_INT fieldsize,
++			     const unsigned HOST_WIDE_INT accesspos,
++			     const unsigned HOST_WIDE_INT accesssize)
++{
++  if (fieldpos == accesspos && fieldsize == accesssize)
++    return true;
++  if (accesspos >= fieldpos && accesspos <= (fieldpos + fieldsize))
++    return true;
++  if (accesspos < fieldpos && (accesspos + accesssize > fieldpos))
++    return true;
++  
++  return false;
++}
++
+ /* Given a COMPONENT_REF T, return the constraint_expr for it.  */
+ 
+ static struct constraint_expr
+@@ -2000,8 +2019,27 @@
+ 	 we may have to do something cute here.  */
+       
+       if (result.offset < get_varinfo (result.var)->fullsize)	
+-	result.var = first_vi_for_offset (get_varinfo (result.var), 
+-					  result.offset)->id;
++	{
++	  /* It's also not true that the constraint will actually start at the
++	     right offset, it may start in some padding.  We only care about
++	     setting the constraint to the first actual field it touches, so
++	     walk to find it.  */ 
++	  varinfo_t curr;
++	  for (curr = get_varinfo (result.var); curr; curr = curr->next)
++	    {
++	      if (offset_overlaps_with_access (curr->offset, curr->size,
++					       result.offset, bitsize))
++		{
++		  result.var = curr->id;
++		  break;
++
++		}
++	    }
++	  /* assert that we found *some* field there. The user couldn't be
++	     accessing *only* padding.  */
++	     
++	  gcc_assert (curr);
++	}
+       else
+ 	if (dump_file && (dump_flags & TDF_DETAILS))
+ 	  fprintf (dump_file, "Access to past the end of variable, ignoring\n");
================================================================