Fix source position for stack traces with optimized top function.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 17448)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -518,6 +518,7 @@
   friend class DoubleToSmiInstr;
   friend class DoubleToDoubleInstr;
   friend class InvokeMathCFunctionInstr;
+  friend class FlowGraphOptimizer;
 
   intptr_t deopt_id_;
   intptr_t lifetime_position_;  // Position used by register allocator.
@@ -1397,7 +1398,7 @@
 
   intptr_t token_pos() const { return token_pos_; }
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -1418,7 +1419,7 @@
 
   intptr_t token_pos() const { return token_pos_; }
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -1895,7 +1896,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return false; }
 
@@ -1942,7 +1943,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return false; }
 
@@ -1984,7 +1985,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -2214,7 +2215,9 @@
 
 
 inline bool BranchInstr::CanDeoptimize() const {
-  return comparison()->CanDeoptimize();
+  // Branches need a deoptimization info in checked mode if they
+  // can throw a type check error.
+  return comparison()->CanDeoptimize() || is_checked();
 }
 
 
@@ -2862,7 +2865,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -2939,7 +2942,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -3156,7 +3159,7 @@
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return true; }
 
@@ -3305,7 +3308,7 @@
   DECLARE_INSTRUCTION(CloneContext)
   virtual RawAbstractType* CompileType() const;
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return false; }
 
@@ -3905,7 +3908,7 @@
 
   virtual intptr_t ArgumentCount() const { return 0; }
 
-  virtual bool CanDeoptimize() const { return false; }
+  virtual bool CanDeoptimize() const { return true; }
 
   virtual bool HasSideEffect() const { return false; }