re PR tree-optimization/33870 (miscompiles sqlite)

	PR 33870
	* tree.h (struct tree_struct_field_tag): Add field in_nested_struct.
	(SFT_IN_NESTED_STRUCT): Define.
	* tree-dfa.c (dump_subvars_for): Show offset of each
	sub-var.
	* tree-flow.h (struct fieldoff): Add field in_nested_struct.
	* tree-ssa-structalias.c (struct variable_info): Likewise.
	(push_fields_onto_fieldstack): If OFFSET is positive,
	set in_nested_struct.
	(create_variable_info_for): Copy setting of
	in_nested_struct from the field offset object.
	(set_uids_in_ptset): Set SFT_IN_NESTED_STRUCT from the
	variable info object.
	* tree-ssa-operands.c (add_vars_for_offset): If VAR
	belongs to a nested structure, adjust OFFSET by
	SFT_OFFSET(VAR).

testsuite/ChangeLog

	* gcc.c-torture/execute/pr33870.x: Remove.

From-SVN: r129976

1 files changed, 23 insertions, 1 deletions

diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 0212499..2d3a40a 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -253,6 +253,15 @@ struct variable_info
      variable.  This is used for C++ placement new.  */
   unsigned int no_tbaa_pruning : 1;
 
+  /* True if this variable is inside a structure nested in the
+     structure for the base variable.  For instance, in 
+     struct X { int a; struct Y { int b; int c; } }, the variables for
+     fields 'b' and 'c' are inside a nested structure.  We are not
+     interested in tracking how many levels of nesting, just whether
+     there is nesting at all.  This is later used to adjust offsets
+     for pointers pointing into sub-structures.  */
+  unsigned int in_nested_struct : 1;
+
   /* Points-to set for this variable.  */
   bitmap solution;
 
@@ -4133,6 +4142,12 @@ push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
 		pair->alias_set = get_alias_set (addressable_type);
 	      else
 		pair->alias_set = -1;
+
+	      /* If the base offset is positive, this field belongs to
+		 a structure nested inside the base structure.  */
+	      if (offset > 0)
+		pair->in_nested_struct = true;
+
 	      count++;
 	    }
 	  else
@@ -4181,6 +4196,12 @@ push_fields_onto_fieldstack (tree type, VEC(fieldoff_s,heap) **fieldstack,
 	      pair->alias_set = get_alias_set (addressable_type);
 	    else
 	      pair->alias_set = -1;
+
+	    /* If the base offset is positive, this field belongs to
+	       a structure nested inside the base structure.  */
+	    if (offset > 0)
+	      pair->in_nested_struct = true;
+
 	    count++;
 	  }
 	else
@@ -4491,6 +4512,7 @@ create_variable_info_for (tree decl, const char *name)
 	  newvi->offset = fo->offset;
 	  newvi->size = TREE_INT_CST_LOW (fo->size);
 	  newvi->fullsize = vi->fullsize;
+	  newvi->in_nested_struct = fo->in_nested_struct;
 	  insert_into_field_list (vi, newvi);
 	  VEC_safe_push (varinfo_t, heap, varmap, newvi);
 	  if (is_global && (!flag_whole_program || !in_ipa_mode))
@@ -4743,6 +4765,7 @@ set_uids_in_ptset (tree ptr, bitmap into, bitmap from, bool is_derefed,
 		      || (!is_derefed && !vi->directly_dereferenced)
 		      || alias_sets_conflict_p (ptr_alias_set, var_alias_set))
 		    bitmap_set_bit (into, DECL_UID (sft));
+		  SFT_IN_NESTED_STRUCT (sft) = vi->in_nested_struct;
 		}
 	    }
 	  else
@@ -4946,7 +4969,6 @@ find_what_p_points_to (tree p)
 	    }
 
 	  /* Share the final set of variables when possible.  */
-
 	  finished_solution = BITMAP_GGC_ALLOC ();
 	  stats.points_to_sets_created++;