From 030a8e58de381a6f64d10848050e4106b51ea305 Mon Sep 17 00:00:00 2001
From: David Malcolm <dmalcolm@redhat.com>
Date: Fri, 5 Jun 2020 16:35:59 -0400
Subject: [PATCH 211/315] FIXME: folding of ops on 'unknown'

---
 gcc/analyzer/region-model2.cc | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/gcc/analyzer/region-model2.cc b/gcc/analyzer/region-model2.cc
index a281d26c514..c394756c27c 100644
--- a/gcc/analyzer/region-model2.cc
+++ b/gcc/analyzer/region-model2.cc
@@ -2975,6 +2975,10 @@ const svalue2 *
 region_model2_manager::maybe_fold_unaryop (tree type, enum tree_code op,
 					   const svalue2 *arg)
 {
+  /* Ops on "unknown" are also unknown.  */
+  if (arg->get_kind () == svalue2::SK_UNKNOWN)
+    return get_or_create_unknown_svalue2 (type);
+
   switch (op)
     {
     default: break;
@@ -3131,6 +3135,15 @@ region_model2_manager::maybe_fold_binop (tree type, enum tree_code op,
 				    binop->get_arg1 (), arg1));
 	  }
 
+  // TODO:
+#if 0
+  /* Ops on "unknown" are also unknown (unless we can use one of the
+     identities above).  */
+  if (arg0->get_kind () == svalue2::SK_UNKNOWN
+      || arg1->get_kind () == svalue2::SK_UNKNOWN)
+    return get_or_create_unknown_svalue2 (type);
+#endif
+
   // TODO
 
   return NULL;
@@ -9437,16 +9450,15 @@ test_state_merging ()
   /* Pointers: non-NULL ptrs to different globals: should be unknown.  */
   {
     region_model2 merged (&mgr);
-    /* x == &y vs x == &z in the input models.  */
+    /* x == &y vs x == &z in the input models; these are actually casts
+       of the ptrs to "int".  */
     const svalue2 *merged_x_sval;
     // TODO:
-#if 0
     assert_region_model2s_merge (x, addr_of_y, addr_of_z, &merged,
 				&merged_x_sval);
 
     /* We should get x == unknown in the merged model.  */
     ASSERT_EQ (merged_x_sval->get_kind (), svalue2::SK_UNKNOWN);
-#endif
   }
 
   /* Pointers: non-NULL and non-NULL: ptr to a heap region2.  */
-- 
2.26.2