- fix ICE in first_vi_for_offset.

Changed files:
    gcc-pr22071.patch -> 1.1

diff --git a/gcc-pr22071.patch b/gcc-pr22071.patch
new file mode 100644 (file)
index 0000000..33b7d4f
--- /dev/null
+++ b/gcc-pr22071.patch
@@ -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");