From a2c163ca9e7d3569cc2d58bc188fcd466dfe2ff7 Mon Sep 17 00:00:00 2001
From: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org>
Date: Wed, 12 Oct 2016 13:48:07 +1100
Subject: [PATCH 1/3] Add-nonnull-to-pointer-from-VRP

---
 gcc/tree-ssa-alias.c       |  4 ++--
 gcc/tree-ssa-alias.h       |  2 +-
 gcc/tree-ssa-ccp.c         |  2 +-
 gcc/tree-ssa-structalias.c | 13 ++++++++-----
 gcc/tree-ssanames.c        | 22 ++++++++++++++++++++++
 gcc/tree-ssanames.h        |  2 ++
 gcc/tree-vrp.c             | 44 +++++++++++++++++++++++++++++---------------
 7 files changed, 65 insertions(+), 24 deletions(-)

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 01bef17..dff11b1 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -515,8 +515,8 @@ dump_points_to_solution (FILE *file, struct pt_solution *pt)
   if (pt->ipa_escaped)
     fprintf (file, ", points-to unit escaped");
 
-  if (pt->null)
-    fprintf (file, ", points-to NULL");
+  if (!pt->null)
+    fprintf (file, ", points-to non NULL");
 
   if (pt->vars)
     {
diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
index 6680cc0..27a06fc 100644
--- a/gcc/tree-ssa-alias.h
+++ b/gcc/tree-ssa-alias.h
@@ -146,7 +146,7 @@ extern void dump_alias_stats (FILE *);
 /* In tree-ssa-structalias.c  */
 extern unsigned int compute_may_aliases (void);
 extern bool pt_solution_empty_p (struct pt_solution *);
-extern bool pt_solution_singleton_p (struct pt_solution *, unsigned *);
+extern bool pt_solution_singleton_or_null_p (struct pt_solution *, unsigned *);
 extern bool pt_solution_includes_global (struct pt_solution *);
 extern bool pt_solution_includes (struct pt_solution *, const_tree);
 extern bool pt_solutions_intersect (struct pt_solution *, struct pt_solution *);
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index fe9a313..61754d8 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -2135,7 +2135,7 @@ fold_builtin_alloca_with_align (gimple *stmt)
       {
 	bool singleton_p;
 	unsigned uid;
-	singleton_p = pt_solution_singleton_p (&pi->pt, &uid);
+	singleton_p = pt_solution_singleton_or_null_p (&pi->pt, &uid);
 	gcc_assert (singleton_p);
 	SET_DECL_PT_UID (var, uid);
       }
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 2a4ab2f..d451ba2 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -6382,6 +6382,8 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi)
 
   *slot = pt = XOBNEW (&final_solutions_obstack, struct pt_solution);
   memset (pt, 0, sizeof (struct pt_solution));
+  /* Conservatively set to NULL from PTA (to true). */
+  pt->null = 1;
 
   /* Translate artificial variables into SSA_NAME_PTR_INFO
      attributes.  */
@@ -6391,9 +6393,7 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi)
 
       if (vi->is_artificial_var)
 	{
-	  if (vi->id == nothing_id)
-	    pt->null = 1;
-	  else if (vi->id == escaped_id)
+	  if (vi->id == escaped_id)
 	    {
 	      if (in_ipa_mode)
 		pt->ipa_escaped = 1;
@@ -6451,6 +6451,7 @@ find_what_p_points_to (tree fndecl, tree p)
   struct ptr_info_def *pi;
   tree lookup_p = p;
   varinfo_t vi;
+  bool nonnull = get_ptr_nonnull (p);
 
   /* For parameters, get at the points-to set for the actual parm
      decl.  */
@@ -6466,6 +6467,8 @@ find_what_p_points_to (tree fndecl, tree p)
 
   pi = get_ptr_info (p);
   pi->pt = find_what_var_points_to (fndecl, vi);
+  if (nonnull)
+    set_ptr_nonnull (p);
 }
 
 
@@ -6599,10 +6602,10 @@ pt_solution_empty_p (struct pt_solution *pt)
    return the var uid in *UID.  */
 
 bool
-pt_solution_singleton_p (struct pt_solution *pt, unsigned *uid)
+pt_solution_singleton_or_null_p (struct pt_solution *pt, unsigned *uid)
 {
   if (pt->anything || pt->nonlocal || pt->escaped || pt->ipa_escaped
-      || pt->null || pt->vars == NULL
+      || pt->vars == NULL
       || !bitmap_single_bit_set_p (pt->vars))
     return false;
 
diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c
index 64ab13a..1d2ec01 100644
--- a/gcc/tree-ssanames.c
+++ b/gcc/tree-ssanames.c
@@ -374,6 +374,28 @@ get_range_info (const_tree name, wide_int *min, wide_int *max)
   return SSA_NAME_RANGE_TYPE (name);
 }
 
+/* Set nonnull attribute to pointer NAME.  */
+
+void
+set_ptr_nonnull (tree name)
+{
+  gcc_assert (POINTER_TYPE_P (TREE_TYPE (name)));
+  struct ptr_info_def *pi = get_ptr_info (name);
+  pi->pt.null = 0;
+}
+
+/* Return nonnull attribute of pointer NAME.  */
+bool
+get_ptr_nonnull (const_tree name)
+{
+  gcc_assert (POINTER_TYPE_P (TREE_TYPE (name)));
+  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);
+  if (pi == NULL
+      || pi->pt.anything)
+    return false;
+  return !pi->pt.null;
+}
+
 /* Change non-zero bits bitmask of NAME.  */
 
 void
diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h
index 4496e1d..d39cc9d 100644
--- a/gcc/tree-ssanames.h
+++ b/gcc/tree-ssanames.h
@@ -88,6 +88,8 @@ extern void set_ptr_info_alignment (struct ptr_info_def *, unsigned int,
 extern void adjust_ptr_info_misalignment (struct ptr_info_def *,
 					  unsigned int);
 extern struct ptr_info_def *get_ptr_info (tree);
+extern void set_ptr_nonnull (tree);
+extern bool get_ptr_nonnull (const_tree);
 
 extern tree copy_ssa_name_fn (struct function *, tree, gimple *);
 extern void duplicate_ssa_name_ptr_info (tree, struct ptr_info_def *);
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 8a129c6..7e4f947 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -10603,18 +10603,24 @@ vrp_finalize (bool warn_array_bounds_p)
       {
 	tree name = ssa_name (i);
 
-      if (!name
-	  || POINTER_TYPE_P (TREE_TYPE (name))
-	  || (vr_value[i]->type == VR_VARYING)
-	  || (vr_value[i]->type == VR_UNDEFINED))
-	continue;
+	if (!name
+	    || (vr_value[i]->type == VR_VARYING)
+	    || (vr_value[i]->type == VR_UNDEFINED)
+	    || (TREE_CODE (vr_value[i]->min) != INTEGER_CST)
+	    || (TREE_CODE (vr_value[i]->max) != INTEGER_CST))
+	  continue;
 
-      if ((TREE_CODE (vr_value[i]->min) == INTEGER_CST)
-	  && (TREE_CODE (vr_value[i]->max) == INTEGER_CST)
-	  && (vr_value[i]->type == VR_RANGE
-	      || vr_value[i]->type == VR_ANTI_RANGE))
-	set_range_info (name, vr_value[i]->type, vr_value[i]->min,
-			vr_value[i]->max);
+	if (POINTER_TYPE_P (TREE_TYPE (name))
+	    && ((vr_value[i]->type == VR_RANGE
+		 && range_includes_zero_p (vr_value[i]->min,
+					   vr_value[i]->max) == 0)
+		|| (vr_value[i]->type == VR_ANTI_RANGE
+		    && range_includes_zero_p (vr_value[i]->min,
+					      vr_value[i]->max) == 1)))
+	  set_ptr_nonnull (name);
+	else if (!POINTER_TYPE_P (TREE_TYPE (name)))
+	  set_range_info (name, vr_value[i]->type, vr_value[i]->min,
+			  vr_value[i]->max);
       }
 
   substitute_and_fold (op_with_constant_singleton_value_range,
@@ -10817,17 +10823,25 @@ evrp_dom_walker::before_dom_children (basic_block bb)
 	  def_operand_p def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF);
 	  /* Set the SSA with the value range.  */
 	  if (def_p
-	      && TREE_CODE (DEF_FROM_PTR (def_p)) == SSA_NAME
-	      && INTEGRAL_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p))))
+	      && TREE_CODE (DEF_FROM_PTR (def_p)) == SSA_NAME)
 	    {
 	      tree def = DEF_FROM_PTR (def_p);
 	      value_range *vr = get_value_range (def);
 
-	      if ((vr->type == VR_RANGE
-		   || vr->type == VR_ANTI_RANGE)
+	      if (INTEGRAL_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p)))
+		  && (vr->type == VR_RANGE
+		      || vr->type == VR_ANTI_RANGE)
 		  && (TREE_CODE (vr->min) == INTEGER_CST)
 		  && (TREE_CODE (vr->max) == INTEGER_CST))
 		set_range_info (def, vr->type, vr->min, vr->max);
+	      else if (POINTER_TYPE_P (TREE_TYPE (DEF_FROM_PTR (def_p)))
+		       && ((vr->type == VR_RANGE
+			    && range_includes_zero_p (vr->min,
+						      vr->max) == 0)
+			   || (vr->type == VR_ANTI_RANGE
+			       && range_includes_zero_p (vr->min,
+							 vr->max) == 1)))
+		set_ptr_nonnull (def);
 	    }
 	}
       else
-- 
2.7.4

