tree-ssa-structalias.c (struct variable_info): Add is_full_var flag.

2008-07-07  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-structalias.c (struct variable_info): Add is_full_var flag.
	(new_var_info): Set it to false.
	(solution_set_add): Correctly handle pointers outside a var and
	inside a field.
	(type_safe): Treat variables with is_full_var properly.
	(do_sd_constraint): Likewise.
	(do_ds_constraint): Likewise.
	(process_constraint): Remove zeroing offset for !use_field_sensitive.
	(get_constraint_for_ptr_offset): New function.
	(get_constraint_for_component_ref): For addresses at least include
	the last field of the variable.  Handle is_full_vars properly.
	(get_constraint_for_1): Factor common code, handle POINTER_PLUS_EXPR.
	(handle_ptr_arith): Remove.
	(find_func_aliases): Simplify assignment handling.
	(create_function_info_for): For parameter and result varinfos set
	is_full_var flag.
	(create_variable_info_for): Set is_full_var flag whenever we
	just created a single varinfo for a decl.
	(init_alias_vars): Initialize use_field_sensitive from
	max-fields-for-field-sensitive parameter.

	* gcc.dg/torture/pta-ptrarith-1.c: New testcase.
	* gcc.dg/torture/pta-ptrarith-2.c: Likewise.
	* gcc.dg/torture/ipa-pta-1.c: Likewise.

From-SVN: r137573

gcc/ChangeLog

 2008-07-07  Richard Guenther  <rguenther@suse.de>
 
+	* tree-ssa-structalias.c (struct variable_info): Add is_full_var flag.
+	(new_var_info): Set it to false.
+	(solution_set_add): Correctly handle pointers outside a var and
+	inside a field.
+	(type_safe): Treat variables with is_full_var properly.
+	(do_sd_constraint): Likewise.
+	(do_ds_constraint): Likewise.
+	(process_constraint): Remove zeroing offset for !use_field_sensitive.
+	(get_constraint_for_ptr_offset): New function.
+	(get_constraint_for_component_ref): For addresses at least include
+	the last field of the variable.  Handle is_full_vars properly.
+	(get_constraint_for_1): Factor common code, handle POINTER_PLUS_EXPR.
+	(handle_ptr_arith): Remove.
+	(find_func_aliases): Simplify assignment handling.
+	(create_function_info_for): For parameter and result varinfos set
+	is_full_var flag.
+	(create_variable_info_for): Set is_full_var flag whenever we
+	just created a single varinfo for a decl.
+	(init_alias_vars): Initialize use_field_sensitive from
+	max-fields-for-field-sensitive parameter.
+
+2008-07-07  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/36713
 	* tree-flow-inline.h (is_call_used): New function.
 	* tree-nrv.c (dest_safe_for_nrv_p): Use it.

gcc/testsuite/ChangeLog

+2008-07-07  Richard Guenther  <rguenther@suse.de>
+
+	* gcc.dg/torture/pta-ptrarith-1.c: New testcase.
+	* gcc.dg/torture/pta-ptrarith-2.c: Likewise.
+	* gcc.dg/torture/ipa-pta-1.c: Likewise.
+
 2008-07-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/36726

gcc/testsuite/gcc.dg/torture/ipa-pta-1.c

+/* { dg-do compile } */
+/* { dg-options "-fipa-pta -fdump-ipa-pta" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+struct X { char x; char y; };
+
+void bar (char *p);
+
+void test1 (char a, char b, char c, char d, char e, char f, char g, char h)
+{
+  char *p = &a;
+  p++;
+  bar (p);
+}
+
+void test2 (struct X a, char b, char c, char d, char e, char f, char g, char h)
+{
+  char *p = &a.x;
+  p++;
+  bar (p);
+}
+
+void test3 (struct X a, char b, char c, char d, char e, char f, char g, char h)
+{
+  char *p = &a.y;
+  bar (p);
+}
+
+void test4 (int a, char b, char c, char d, char e, char f, char g, char h)
+{
+  char *p = (char *)&a;
+  p++;
+  p++;
+  p++;
+  p++;
+  bar (p);
+}
+
+/* { dg-final { scan-ipa-dump "bar.arg0 = { test4.arg0 test3.arg0 test2.arg0 test1.arg0 }" "pta" } } */
+/* { dg-final { cleanup-ipa-dump "pta" } } */

gcc/testsuite/gcc.dg/torture/pta-ptrarith-1.c

+/* { dg-do run } */
+/* { dg-options "-fdump-tree-alias" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+struct Foo {
+  int *p;
+};
+
+void __attribute__((noinline))
+foo (void *p)
+{
+  struct Foo *f = (struct Foo *)p - 1;
+  *f->p = 0;
+}
+
+int bar (void)
+{
+  struct Foo f;
+  int i = 1;
+  f.p = &i;
+  foo (&f + 1);
+  return i;
+}
+extern void abort (void);
+int main()
+{
+  if (bar () != 0)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "ESCAPED = { ESCAPED NONLOCAL f .* i }" "alias" } } */
+/* { dg-final { cleanup-tree-dump "alias" } } */

gcc/testsuite/gcc.dg/torture/pta-ptrarith-2.c

+/* { dg-do run } */
+/* { dg-options "-fdump-tree-alias" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+
+struct Foo {
+  int **p;
+  int **q;
+};
+
+int __attribute__((noinline))
+bar (void)
+{
+  struct Foo f;
+  int j, i = 1;
+  char *p;
+  int *x = &i;
+  int *y = &j;
+  f.p = &y;
+  f.q = &x;
+  p = (char *)&f;
+  for (j = 0; j < sizeof (int *); ++j)
+    p++;
+  return ***(int ***)p;
+}
+extern void abort (void);
+int main()
+{
+  if (bar () != 1)
+    abort ();
+  return 0;
+}
+
+/* In theory = { i } is the correct solution.  But it's not easy to scan
+   for that reliably, so just use what we create now.  */
+/* { dg-final { scan-tree-dump "= { i j }" "alias" } } */
+/* { dg-final { cleanup-tree-dump "alias" } } */

gcc/tree-ssa-structalias.c

@@ -220,6 +220,9 @@ struct variable_info
   /* True for variables whose size is not known or variable.  */
   unsigned int is_unknown_size_var:1;
 
+  /* True for (sub-)fields that represent a whole variable.  */
+  unsigned int is_full_var : 1;
+
   /* True if this is a heap variable.  */
   unsigned int is_heap_var:1;
 
@@ -373,6 +376,7 @@ new_var_info (tree t, unsigned int id, const char *name)
   ret->is_heap_var = false;
   ret->is_special_var = false;
   ret->is_unknown_size_var = false;
+  ret->is_full_var = false;
   var = t;
   if (TREE_CODE (var) == SSA_NAME)
     var = SSA_NAME_VAR (var);
@@ -752,22 +756,32 @@ solution_set_add (bitmap set, unsigned HOST_WIDE_INT offset)
 
   EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi)
     {
-      /* If this is a properly sized variable, only add offset if it's
-	 less than end.  Otherwise, it is globbed to a single
-	 variable.  */
+      varinfo_t vi = get_varinfo (i);
 
-      if ((get_varinfo (i)->offset + offset) < get_varinfo (i)->fullsize)
+      /* If this is a variable with just one field just set its bit
+         in the result.  */
+      if (vi->is_artificial_var
+	  || vi->is_unknown_size_var
+	  || vi->is_full_var)
+	bitmap_set_bit (result, i);
+      else
 	{
-	  unsigned HOST_WIDE_INT fieldoffset = get_varinfo (i)->offset + offset;
-	  varinfo_t v = first_vi_for_offset (get_varinfo (i), fieldoffset);
+	  unsigned HOST_WIDE_INT fieldoffset = vi->offset + offset;
+	  varinfo_t v = first_vi_for_offset (vi, fieldoffset);
+	  /* If the result is outside of the variable use the last field.  */
 	  if (!v)
-	    continue;
+	    {
+	      v = vi;
+	      while (v->next != NULL)
+		v = v->next;
+	    }
 	  bitmap_set_bit (result, v->id);
-	}
-      else if (get_varinfo (i)->is_artificial_var
-	       || get_varinfo (i)->is_unknown_size_var)
-	{
-	  bitmap_set_bit (result, i);
+	  /* If the result is not exactly at fieldoffset include the next
+	     field as well.  See get_constraint_for_ptr_offset for more
+	     rationale.  */
+	  if (v->offset != fieldoffset
+	      && v->next != NULL)
+	    bitmap_set_bit (result, v->next->id);
 	}
     }
 
@@ -1375,7 +1389,8 @@ type_safe (unsigned int n, unsigned HOST_WIDE_INT *offset)
      0.  */
   if (ninfo->is_special_var
       || ninfo->is_artificial_var
-      || ninfo->is_unknown_size_var)
+      || ninfo->is_unknown_size_var
+      || ninfo->is_full_var)
     {
       *offset = 0;
       return true;
@@ -1415,7 +1430,11 @@ do_sd_constraint (constraint_graph_t graph, constraint_t c,
          sub-fields off.  This avoids quadratic behavior.  */
       EXECUTE_IF_SET_IN_BITMAP (delta, 0, j, bi)
 	{
-	  varinfo_t v = lookup_vi_for_tree (get_varinfo (j)->decl);
+	  varinfo_t v = get_varinfo (j);
+	  if (v->is_full_var)
+	    continue;
+
+	  v = lookup_vi_for_tree (v->decl);
 	  if (v->next != NULL)
 	    {
 	      if (vars == NULL)
@@ -1455,6 +1474,7 @@ do_sd_constraint (constraint_graph_t graph, constraint_t c,
 	  unsigned int t;
 
 	  v = first_vi_for_offset (get_varinfo (j), fieldoffset);
+	  /* If the access is outside of the variable we can ignore it.  */
 	  if (!v)
 	    continue;
 	  t = find (v->id);
@@ -1507,9 +1527,14 @@ do_ds_constraint (constraint_t c, bitmap delta)
 	 unsigned HOST_WIDE_INT fieldoffset = jvi->offset + loff;
 	 varinfo_t v;
 
-	 v = first_vi_for_offset (get_varinfo (j), fieldoffset);
-	 if (!v)
-	   continue;
+	 v = get_varinfo (j);
+	 if (!v->is_full_var)
+	   {
+	     v = first_vi_for_offset (v, fieldoffset);
+	     /* If the access is outside of the variable we can ignore it.  */
+	     if (!v)
+	       continue;
+	   }
 	 t = find (v->id);
 
 	 if (bitmap_set_bit (get_varinfo (t)->solution, anything_id)
@@ -1535,6 +1560,7 @@ do_ds_constraint (constraint_t c, bitmap delta)
 	  bitmap tmp;
 
 	  v = first_vi_for_offset (get_varinfo (j), fieldoffset);
+	  /* If the access is outside of the variable we can ignore it.  */
 	  if (!v)
 	    continue;
 	  t = find (v->id);
@@ -2597,12 +2623,6 @@ process_constraint (constraint_t t)
   gcc_assert (rhs.var < VEC_length (varinfo_t, varmap));
   gcc_assert (lhs.var < VEC_length (varinfo_t, varmap));
 
-  if (!use_field_sensitive)
-    {
-      t->rhs.offset = 0;
-      t->lhs.offset = 0;
-    }
-
   /* ANYTHING == ANYTHING is pointless.  */
   if (lhs.var == anything_id && rhs.var == anything_id)
     return;
@@ -2678,6 +2698,119 @@ bitpos_of_field (const tree fdecl)
 }
 
 
+/* Get constraint expressions for offsetting PTR by OFFSET.  Stores the
+   resulting constraint expressions in *RESULTS.  */
+
+static void
+get_constraint_for_ptr_offset (tree ptr, tree offset,
+			       VEC (ce_s, heap) **results)
+{
+  struct constraint_expr *c;
+  unsigned int j, n;
+  unsigned HOST_WIDE_INT rhsunitoffset, rhsoffset;
+
+  /* If we do not do field-sensitive PTA adding offsets to pointers
+     does not change the points-to solution.  */
+  if (!use_field_sensitive)
+    {
+      get_constraint_for (ptr, results);
+      return;
+    }
+
+  /* If the offset is not a non-negative integer constant that fits
+     in a HOST_WIDE_INT, we have to fall back to a conservative
+     solution which includes all sub-fields of all pointed-to
+     variables of ptr.
+     ???  As we do not have the ability to express this, fall back
+     to anything.  */
+  if (!host_integerp (offset, 1))
+    {
+      struct constraint_expr temp;
+      temp.var = anything_id;
+      temp.type = SCALAR;
+      temp.offset = 0;
+      VEC_safe_push (ce_s, heap, *results, &temp);
+      return;
+    }
+
+  /* Make sure the bit-offset also fits.  */
+  rhsunitoffset = TREE_INT_CST_LOW (offset);
+  rhsoffset = rhsunitoffset * BITS_PER_UNIT;
+  if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
+    {
+      struct constraint_expr temp;
+      temp.var = anything_id;
+      temp.type = SCALAR;
+      temp.offset = 0;
+      VEC_safe_push (ce_s, heap, *results, &temp);
+      return;
+    }
+
+  get_constraint_for (ptr, results);
+  if (rhsoffset == 0)
+    return;
+
+  /* As we are eventually appending to the solution do not use
+     VEC_iterate here.  */
+  n = VEC_length (ce_s, *results);
+  for (j = 0; j < n; j++)
+    {
+      varinfo_t curr;
+      c = VEC_index (ce_s, *results, j);
+      curr = get_varinfo (c->var);
+
+      if (c->type == ADDRESSOF
+	  && !curr->is_full_var)
+	{
+	  varinfo_t temp, curr = get_varinfo (c->var);
+
+	  /* Search the sub-field which overlaps with the
+	     pointed-to offset.  As we deal with positive offsets
+	     only, we can start the search from the current variable.  */
+	  temp = first_vi_for_offset (curr, curr->offset + rhsoffset);
+
+	  /* If the result is outside of the variable we have to provide
+	     a conservative result, as the variable is still reachable
+	     from the resulting pointer (even though it technically
+	     cannot point to anything).  The last sub-field is such
+	     a conservative result.
+	     ???  If we always had a sub-field for &object + 1 then
+	     we could represent this in a more precise way.  */
+	  if (temp == NULL)
+	    {
+	      temp = curr;
+	      while (temp->next != NULL)
+		temp = temp->next;
+	      continue;
+	    }
+
+	  /* If the found variable is not exactly at the pointed to
+	     result, we have to include the next variable in the
+	     solution as well.  Otherwise two increments by offset / 2
+	     do not result in the same or a conservative superset
+	     solution.  */
+	  if (temp->offset != curr->offset + rhsoffset
+	      && temp->next != NULL)
+	    {
+	      struct constraint_expr c2;
+	      c2.var = temp->next->id;
+	      c2.type = ADDRESSOF;
+	      c2.offset = 0;
+	      VEC_safe_push (ce_s, heap, *results, &c2);
+	    }
+	  c->var = temp->id;
+	  c->offset = 0;
+	}
+      else if (c->type == ADDRESSOF
+	       /* If this varinfo represents a full variable just use it.  */
+	       && curr->is_full_var)
+	c->offset = 0;
+      else
+	c->offset = rhsoffset;
+    }
+}
+
+
 /* Given a COMPONENT_REF T, return the constraint_expr vector for it.
    If address_p is true the result will be taken its address of.  */
 
@@ -2714,15 +2847,18 @@ get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
   /* Pretend to take the address of the base, we'll take care of
      adding the required subset of sub-fields below.  */
   get_constraint_for_1 (t, results, true);
-  result = VEC_last (ce_s, *results);
-
   gcc_assert (VEC_length (ce_s, *results) == 1);
+  result = VEC_last (ce_s, *results);
 
   /* This can also happen due to weird offsetof type macros.  */
   if (TREE_CODE (t) != ADDR_EXPR && result->type == ADDRESSOF)
     result->type = SCALAR;
 
-  if (result->type == SCALAR)
+  if (result->type == SCALAR
+      && get_varinfo (result->var)->is_full_var)
+    /* For single-field vars do not bother about the offset.  */
+    result->offset = 0;
+  else if (result->type == SCALAR)
     {
       /* In languages like C, you can access one past the end of an
 	 array.  You aren't allowed to dereference it, so we can
@@ -2751,12 +2887,25 @@ get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
 		    break;
 		}
 	    }
-	  /* assert that we found *some* field there. The user couldn't be
-	     accessing *only* padding.  */
-	  /* Still the user could access one past the end of an array
-	     embedded in a struct resulting in accessing *only* padding.  */
-	  gcc_assert (VEC_length (ce_s, *results) >= 1
-		      || ref_contains_array_ref (orig_t));
+	  /* If we are going to take the address of this field then
+	     to be able to compute reachability correctly add at least
+	     the last field of the variable.  */
+	  if (address_p
+	      && VEC_length (ce_s, *results) == 0)
+	    {
+	      curr = get_varinfo (cexpr.var);
+	      while (curr->next != NULL)
+		curr = curr->next;
+	      cexpr.var = curr->id;
+	      VEC_safe_push (ce_s, heap, *results, &cexpr);
+	    }
+	  else
+	    /* Assert that we found *some* field there. The user couldn't be
+	       accessing *only* padding.  */
+	    /* Still the user could access one past the end of an array
+	       embedded in a struct resulting in accessing *only* padding.  */
+	    gcc_assert (VEC_length (ce_s, *results) >= 1
+			|| ref_contains_array_ref (orig_t));
 	}
       else if (bitmaxsize == 0)
 	{
@@ -2900,24 +3049,10 @@ get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
 		VEC_safe_push (ce_s, heap, *results, &temp);
 		return;
 	      }
-	    else
-	      {
-		temp.var = anything_id;
-		temp.type = SCALAR;
-		temp.offset = 0;
-		VEC_safe_push (ce_s, heap, *results, &temp);
-		return;
-	      }
 	    break;
-	  default:
-	    {
-	      temp.type = ADDRESSOF;
-	      temp.var = anything_id;
-	      temp.offset = 0;
-	      VEC_safe_push (ce_s, heap, *results, &temp);
-	      return;
-	    }
+	  default:;
 	  }
+	break;
       }
     case tcc_reference:
       {
@@ -2934,15 +3069,9 @@ get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
 	  case COMPONENT_REF:
 	    get_constraint_for_component_ref (t, results, address_p);
 	    return;
-	  default:
-	    {
-	      temp.type = ADDRESSOF;
-	      temp.var = anything_id;
-	      temp.offset = 0;
-	      VEC_safe_push (ce_s, heap, *results, &temp);
-	      return;
-	    }
+	  default:;
 	  }
+	break;
       }
     case tcc_unary:
       {
@@ -2963,15 +3092,19 @@ get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
 
 	      /* FALLTHRU  */
 	    }
-	  default:
-	    {
-	      temp.type = ADDRESSOF;
-	      temp.var = anything_id;
-	      temp.offset = 0;
-	      VEC_safe_push (ce_s, heap, *results, &temp);
-	      return;
-	    }
+	  default:;
 	  }
+	break;
+      }
+    case tcc_binary:
+      {
+	if (TREE_CODE (t) == POINTER_PLUS_EXPR)
+	  {
+	    get_constraint_for_ptr_offset (TREE_OPERAND (t, 0),
+					   TREE_OPERAND (t, 1), results);
+	    return;
+	  }
+	break;
       }
     case tcc_exceptional:
       {
@@ -2982,37 +3115,28 @@ get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
 	      get_constraint_for_1 (PHI_RESULT (t), results, address_p);
 	      return;
 	    }
-	    break;
 	  case SSA_NAME:
 	    {
 	      get_constraint_for_ssa_var (t, results, address_p);
 	      return;
 	    }
-	    break;
-	  default:
-	    {
-	      temp.type = ADDRESSOF;
-	      temp.var = anything_id;
-	      temp.offset = 0;
-	      VEC_safe_push (ce_s, heap, *results, &temp);
-	      return;
-	    }
+	  default:;
 	  }
+	break;
       }
     case tcc_declaration:
       {
 	get_constraint_for_ssa_var (t, results, address_p);
 	return;
       }
-    default:
-      {
-	temp.type = ADDRESSOF;
-	temp.var = anything_id;
-	temp.offset = 0;
-	VEC_safe_push (ce_s, heap, *results, &temp);
-	return;
-      }
+    default:;
     }
+
+  /* The default fallback is a constraint from anything.  */
+  temp.type = ADDRESSOF;
+  temp.var = anything_id;
+  temp.offset = 0;
+  VEC_safe_push (ce_s, heap, *results, &temp);
 }
 
 /* Given a gimple tree T, return the constraint expression vector for it.  */
@@ -3298,80 +3422,6 @@ do_structure_copy (tree lhsop, tree rhsop)
     }
 }
 
-
-/* Handle pointer arithmetic EXPR when creating aliasing constraints.
-   Expressions of the type PTR + CST can be handled in two ways:
-
-   1- If the constraint for PTR is ADDRESSOF for a non-structure
-      variable, then we can use it directly because adding or
-      subtracting a constant may not alter the original ADDRESSOF
-      constraint (i.e., pointer arithmetic may not legally go outside
-      an object's boundaries).
-
-   2- If the constraint for PTR is ADDRESSOF for a structure variable,
-      then if CST is a compile-time constant that can be used as an
-      offset, we can determine which sub-variable will be pointed-to
-      by the expression.
-
-   Return true if the expression is handled.  For any other kind of
-   expression, return false so that each operand can be added as a
-   separate constraint by the caller.  */
-
-static bool
-handle_ptr_arith (VEC (ce_s, heap) *lhsc, tree expr)
-{
-  tree op0, op1;
-  struct constraint_expr *c, *c2;
-  unsigned int i = 0;
-  unsigned int j = 0;
-  VEC (ce_s, heap) *temp = NULL;
-  unsigned HOST_WIDE_INT rhsunitoffset, rhsoffset;
-
-  if (TREE_CODE (expr) != POINTER_PLUS_EXPR)
-    return false;
-
-  op0 = TREE_OPERAND (expr, 0);
-  op1 = TREE_OPERAND (expr, 1);
-  gcc_assert (POINTER_TYPE_P (TREE_TYPE (op0)));
-
-  /* If the offset is not a non-negative integer constant that fits
-     in a HOST_WIDE_INT, we cannot handle it here.  */
-  if (!host_integerp (op1, 1))
-    return false;
-
-  /* Make sure the bit-offset also fits.  */
-  rhsunitoffset = TREE_INT_CST_LOW (op1);
-  rhsoffset = rhsunitoffset * BITS_PER_UNIT;
-  if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
-    return false;
-
-  get_constraint_for (op0, &temp);
-
-  for (i = 0; VEC_iterate (ce_s, lhsc, i, c); i++)
-    for (j = 0; VEC_iterate (ce_s, temp, j, c2); j++)
-      {
-	if (c2->type == ADDRESSOF && rhsoffset != 0)
-	  {
-	    varinfo_t temp = get_varinfo (c2->var);
-
-	    /* An access one after the end of an array is valid,
-	       so simply punt on accesses we cannot resolve.  */
-	    temp = first_vi_for_offset (temp, rhsoffset);
-	    if (temp == NULL)
-	      continue;
-	    c2->var = temp->id;
-	    c2->offset = 0;
-	  }
-	else
-	  c2->offset = rhsoffset;
-	process_constraint (new_constraint (*c, *c2));
-      }
-
-  VEC_free (ce_s, heap, temp);
-
-  return true;
-}
-
 /* Create a constraint ID = OP.  */
 
 static void
@@ -3771,89 +3821,29 @@ find_func_aliases (tree origt)
 	    }
 	}
     }
-  /* Otherwise, just a regular assignment statement.  */
-  else if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
+  /* Otherwise, just a regular assignment statement.  Only care about
+     operations with pointer result, others are dealt with as escape
+     points if they have pointer operands.  */
+  else if (TREE_CODE (t) == GIMPLE_MODIFY_STMT
+	   && could_have_pointers (GIMPLE_STMT_OPERAND (t, 0)))
     {
       tree lhsop = GIMPLE_STMT_OPERAND (t, 0);
       tree rhsop = GIMPLE_STMT_OPERAND (t, 1);
-      int i;
 
-      if (AGGREGATE_TYPE_P (TREE_TYPE (lhsop))
-	  && AGGREGATE_TYPE_P (TREE_TYPE (rhsop)))
-	{
-	  do_structure_copy (lhsop, rhsop);
-	}
+      if (AGGREGATE_TYPE_P (TREE_TYPE (lhsop)))
+	do_structure_copy (lhsop, rhsop);
       else
 	{
-	  /* Only care about operations with pointers, structures
-	     containing pointers, dereferences, and call expressions.  */
-	  if (could_have_pointers (lhsop)
-	      || TREE_CODE (rhsop) == CALL_EXPR)
+	  unsigned int j;
+	  get_constraint_for (lhsop, &lhsc);
+	  get_constraint_for (rhsop, &rhsc);
+	  for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
 	    {
-	      get_constraint_for (lhsop, &lhsc);
-	      switch (TREE_CODE_CLASS (TREE_CODE (rhsop)))
-		{
-		  /* RHS that consist of unary operations,
-		     exceptional types, or bare decls/constants, get
-		     handled directly by get_constraint_for.  */
-		  case tcc_reference:
-		  case tcc_declaration:
-		  case tcc_constant:
-		  case tcc_exceptional:
-		  case tcc_expression:
-		  case tcc_vl_exp:
-		  case tcc_unary:
-		      {
-			unsigned int j;
-
-			get_constraint_for (rhsop, &rhsc);
-			for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
-			  {
-			    struct constraint_expr *c2;
-			    unsigned int k;
-
-			    for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++)
-			      process_constraint (new_constraint (*c, *c2));
-			  }
-
-		      }
-		    break;
+	      struct constraint_expr *c2;
+	      unsigned int k;
 
-		  case tcc_binary:
-		      {
-			/* For pointer arithmetic of the form
-			   PTR + CST, we can simply use PTR's
-			   constraint because pointer arithmetic is
-			   not allowed to go out of bounds.  */
-			if (handle_ptr_arith (lhsc, rhsop))
-			  break;
-		      }
-		    /* FALLTHRU  */
-
-		  /* Otherwise, walk each operand.  Notice that we
-		     can't use the operand interface because we need
-		     to process expressions other than simple operands
-		     (e.g. INDIRECT_REF, ADDR_EXPR, CALL_EXPR).  */
-		  default:
-		    for (i = 0; i < TREE_OPERAND_LENGTH (rhsop); i++)
-		      {
-			tree op = TREE_OPERAND (rhsop, i);
-			unsigned int j;
-
-			gcc_assert (VEC_length (ce_s, rhsc) == 0);
-			get_constraint_for (op, &rhsc);
-			for (j = 0; VEC_iterate (ce_s, lhsc, j, c); j++)
-			  {
-			    struct constraint_expr *c2;
-			    while (VEC_length (ce_s, rhsc) > 0)
-			      {
-				c2 = VEC_last (ce_s, rhsc);
-				process_constraint (new_constraint (*c, *c2));
-				VEC_pop (ce_s, rhsc);
-			      }
-			  }
-		      }
-		}
+	      for (k = 0; VEC_iterate (ce_s, rhsc, k, c2); k++)
+		process_constraint (new_constraint (*c, *c2));
 	    }
 	}
     }
@@ -4222,8 +4212,7 @@ create_function_info_for (tree decl, const char *name)
   stats.total_vars++;
 
   /* If it's varargs, we don't know how many arguments it has, so we
-     can't do much.
-  */
+     can't do much.  */
   if (is_varargs)
     {
       vi->fullsize = ~0;
@@ -4257,6 +4246,7 @@ create_function_info_for (tree decl, const char *name)
       VEC_safe_push (varinfo_t, heap, varmap, argvi);
       argvi->offset = i;
       argvi->size = 1;
+      argvi->is_full_var = true;
       argvi->fullsize = vi->fullsize;
       insert_into_field_list_sorted (vi, argvi);
       stats.total_vars ++;
@@ -4293,6 +4283,7 @@ create_function_info_for (tree decl, const char *name)
       resultvi->offset = i;
       resultvi->size = 1;
       resultvi->fullsize = vi->fullsize;
+      resultvi->is_full_var = true;
       insert_into_field_list_sorted (vi, resultvi);
       stats.total_vars ++;
       if (DECL_RESULT (decl))
@@ -4411,6 +4402,7 @@ create_variable_info_for (tree decl, const char *name)
 	  vi->is_unknown_size_var = 1;
 	  vi->fullsize = ~0;
 	  vi->size = ~0;
+	  vi->is_full_var = true;
 	  VEC_free (fieldoff_s, heap, fieldstack);
 	  return index;
 	}
@@ -4447,6 +4439,8 @@ create_variable_info_for (tree decl, const char *name)
 	  stats.total_vars++;
 	}
     }
+  else
+    vi->is_full_var = true;
 
   VEC_free (fieldoff_s, heap, fieldstack);
 
@@ -5198,6 +5192,8 @@ init_base_vars (void)
 static void
 init_alias_vars (void)
 {
+  use_field_sensitive = (MAX_FIELDS_FOR_FIELD_SENSITIVE > 1);
+
   bitmap_obstack_initialize (&pta_obstack);
   bitmap_obstack_initialize (&oldpta_obstack);
   bitmap_obstack_initialize (&predbitmap_obstack);