3 files changed, 91 insertions, 3 deletions
diff --git a/gcc/testsuite/g++.dg/warn/pr80635-1.C b/gcc/testsuite/g++.dg/warn/pr80635-1.C
new file mode 100644
index 0000000..8478791
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr80635-1.C
@@ -0,0 +1,46 @@
+// PR tree-optimization/80635
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2 -Wmaybe-uninitialized" }
+
+using size_t = decltype (sizeof (1));
+inline void *operator new (size_t, void *p) { return p; }
+template<typename T>
+struct optional
+{
+  optional () : m_dummy (), live (false) {}
+  void emplace () { new (&m_item) T (); live = true; }
+  ~optional () { if (live) m_item.~T (); }
+
+  union
+  {
+    struct {} m_dummy;
+    T m_item;
+  };
+  bool live;
+};
+
+extern int get ();
+extern void set (int);
+
+struct A
+{
+  A () : m (get ()) {}
+  ~A () { set (m); }	// { dg-bogus "may be used uninitialized in this function" }
+
+  int m;
+};
+
+struct B
+{
+  B ();
+  ~B ();
+};
+
+void func ()
+{
+  optional<A> maybe_a;
+  optional<B> maybe_b;
+
+  maybe_a.emplace ();
+  maybe_b.emplace ();
+}
diff --git a/gcc/testsuite/g++.dg/warn/pr80635-2.C b/gcc/testsuite/g++.dg/warn/pr80635-2.C
new file mode 100644
index 0000000..9f57547
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/pr80635-2.C
@@ -0,0 +1,31 @@
+// PR tree-optimization/80635
+// { dg-do compile { target c++17 } }
+// { dg-options "-O2 -Wmaybe-uninitialized" }
+
+#include <optional>
+
+extern int get ();
+extern void set (int);
+
+struct A
+{
+  A () : m (get ()) {}
+  ~A () { set (m); }	// { dg-bogus "may be used uninitialized in this function" }
+
+  int m;
+};
+
+struct B
+{
+  B ();
+  ~B ();
+};
+
+void func ()
+{
+  std::optional<A> maybe_a;
+  std::optional<B> maybe_b;
+
+  maybe_a.emplace ();
+  maybe_b.emplace ();
+}
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 53eaf9c..8d638ae 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4390,11 +4390,22 @@ vrp_simplify_cond_using_ranges (vr_values *query, gcond *stmt)
       gimple *def_stmt = SSA_NAME_DEF_STMT (op0);
       tree innerop;
 
-      if (!is_gimple_assign (def_stmt)
-	  || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
+      if (!is_gimple_assign (def_stmt))
 	return;
 
-      innerop = gimple_assign_rhs1 (def_stmt);
+      switch (gimple_assign_rhs_code (def_stmt))
+	{
+	CASE_CONVERT:
+	  innerop = gimple_assign_rhs1 (def_stmt);
+	  break;
+	case VIEW_CONVERT_EXPR:
+	  innerop = TREE_OPERAND (gimple_assign_rhs1 (def_stmt), 0);
+	  if (!INTEGRAL_TYPE_P (TREE_TYPE (innerop)))
+	    return;
+	  break;
+	default:
+	  return;
+	}
 
       if (TREE_CODE (innerop) == SSA_NAME
 	  && !POINTER_TYPE_P (TREE_TYPE (innerop))