pr 33870

	* tree.h (strcut tree_memory_tag): add field unpartitionable.
	remove field in_nested_struct.
	(struct tree_struct_field_tag): add field nesting_level.
	(sft_in_nested_struct): remove.
	(sft_nesting_level): define.
	(sft_unpartitionable_p): define.
	* tree-ssa-alias.c (mem_sym_score): if mp->var is not
	partitionable, return long_max.
	(compute_memory_partitions): do not partition sfts marked
	unpartitionable.
	(create_sft): add argument nesting_level.  set
	sft_nesting_level with it.  update all users.
	(create_overlap_variables_for): show nesting level.
	* tree-dfa.c (dump_subvars_for): likewise.
	(dump_variable): likewise.
	show whether the sft is partitionable or not.
	* tree-flow.h (struct fieldoff): remove field
	in_nested_struct.
	add field nesting_level.
	* tree-ssa-structalias.c (struct variable_info): remove
	field in_nested_struct.
	(push_fields_onto_fieldstack): add argument
	nesting_level.  update all users.
	update documentation.
	update pair->nesting_level with nesting_level.
	make recursive calls with nesting_level + 1.
	(set_uids_in_ptset): if an sft is added to the points-to
	set, mark it as unpartitionable.
	* tree-ssa-operands.c (ref_nesting_level): new.
	(add_vars_for_offset): call it.
	add argument full_ref.  update
	callers.
	if var is inside a nested structure and the nesting level
	of full_ref is lower than the nesting level of var,
	adjust offset by the offset of var.

testsuite/ChangeLog
	
	PR 33870
	* gcc.c-torture/execute/pr33870-1.c: New test.
	* gcc.dg/tree-ssa/alias-16.c: New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@130141 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 28 insertions, 8 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index f2e30646d4c..31e04bcca29 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -828,6 +828,13 @@ count_mem_refs (long *num_vuses_p, long *num_vdefs_p,
 static inline long
 mem_sym_score (mem_sym_stats_t mp)
 {
+  /* Unpartitionable SFTs are automatically thrown to the bottom of
+     the list.  They are not stored in partitions, but they are used
+     for computing overall statistics.  */
+  if (TREE_CODE (mp->var) == STRUCT_FIELD_TAG
+      && SFT_UNPARTITIONABLE_P (mp->var))
+    return LONG_MAX;
+
   return mp->frequency_writes * 64 + mp->frequency_reads * 32
          + mp->num_direct_writes * 16 + mp->num_direct_reads * 8
 	 + mp->num_indirect_writes * 4 + mp->num_indirect_reads * 2
@@ -1392,8 +1399,8 @@ update_reference_counts (struct mem_ref_stats_d *mem_ref_stats)
 
 static void
 build_mp_info (struct mem_ref_stats_d *mem_ref_stats,
-                 VEC(mem_sym_stats_t,heap) **mp_info_p,
-		 VEC(tree,heap) **tags_p)
+               VEC(mem_sym_stats_t,heap) **mp_info_p,
+	       VEC(tree,heap) **tags_p)
 {
   tree var;
   referenced_var_iterator rvi;
@@ -1591,6 +1598,15 @@ compute_memory_partitions (void)
       if (!need_to_partition_p (mem_ref_stats))
 	break;
 
+      /* SFTs that are marked unpartitionable should not be added to
+	 partitions.  These SFTs are special because they mark the
+	 first SFT into a structure where a pointer is pointing to.
+	 This is needed by the operand scanner to find adjacent
+	 fields.  See add_vars_for_offset for details.  */
+      if (TREE_CODE (mp_p->var) == STRUCT_FIELD_TAG
+	  && SFT_UNPARTITIONABLE_P (mp_p->var))
+	continue;
+
       mpt = find_partition_for (mp_p);
       estimate_vop_reduction (mem_ref_stats, mp_p, mpt);
     }
@@ -3774,7 +3790,8 @@ get_or_create_used_part_for (size_t uid)
 
 static tree
 create_sft (tree var, tree field, unsigned HOST_WIDE_INT offset,
-	    unsigned HOST_WIDE_INT size, alias_set_type alias_set)
+	    unsigned HOST_WIDE_INT size, alias_set_type alias_set,
+	    unsigned nesting_level)
 {
   tree subvar = create_tag_raw (STRUCT_FIELD_TAG, field, "SFT");
 
@@ -3794,6 +3811,8 @@ create_sft (tree var, tree field, unsigned HOST_WIDE_INT offset,
   SFT_OFFSET (subvar) = offset;
   SFT_SIZE (subvar) = size;
   SFT_ALIAS_SET (subvar) = alias_set;
+  SFT_NESTING_LEVEL (subvar) = nesting_level;
+
   return subvar;
 }
 
@@ -3814,7 +3833,7 @@ create_overlap_variables_for (tree var)
     return;
 
   push_fields_onto_fieldstack (TREE_TYPE (var), &fieldstack, 0, NULL,
-			       TREE_TYPE (var));
+			       TREE_TYPE (var), 0);
   if (VEC_length (fieldoff_s, fieldstack) != 0)
     {
       subvar_t *subvars;
@@ -3897,7 +3916,6 @@ create_overlap_variables_for (tree var)
 	     field, skip it.  Note that we always need the field at
 	     offset 0 so we can properly handle pointers to the
 	     structure.  */
-
 	  if ((fo->offset != 0
 	       && ((fo->offset <= up->minused
 		    && fo->offset + fosize <= up->minused)
@@ -3906,8 +3924,9 @@ create_overlap_variables_for (tree var)
 		  && fosize == lastfosize
 		  && currfotype == lastfotype))
 	    continue;
-	  subvar = create_sft (var, fo->type, fo->offset,
-			       fosize, fo->alias_set);
+
+	  subvar = create_sft (var, fo->type, fo->offset, fosize,
+			       fo->alias_set, fo->nesting_level);
 	  VEC_quick_push (tree, *subvars, subvar);
 
 	  if (dump_file)
@@ -3918,7 +3937,8 @@ create_overlap_variables_for (tree var)
 		       SFT_OFFSET (subvar));
 	      fprintf (dump_file, " size " HOST_WIDE_INT_PRINT_DEC,
 		       SFT_SIZE (subvar));
-	      fprintf (dump_file, "\n");
+	      fprintf (dump_file, " nesting level %d\n",
+		       SFT_NESTING_LEVEL (subvar));
 	    }
 	  
 	  lastfotype = currfotype;