# HG changeset patch
# User Max Brister <max@2bass.com>
# Date 1339091000 18000
# Node ID bab44e3ee2912d9d083f69c8832f5ceb1184b57f
# Parent  78e1457c5bf55393f9b80f8d335f8e1a0f7fc33c
Adding basic error support to JIT

diff --git a/src/pt-jit.cc b/src/pt-jit.cc
--- a/src/pt-jit.cc
+++ b/src/pt-jit.cc
@@ -301,6 +301,12 @@
   casts.resize (next_id + 1);
   identities.resize (next_id + 1, 0);
 
+  // bind global variables
+  lerror_state = new llvm::GlobalVariable (*module, bool_t, false,
+                                           llvm::GlobalValue::ExternalLinkage,
+                                           0, "error_state");
+  engine->addGlobalMapping (lerror_state, reinterpret_cast<void *> (&error_state));
+
   // any with anything is an any op
   llvm::Function *fn;
   llvm::Type *binary_op_type
@@ -334,10 +340,7 @@
                                                  fn->arg_begin (),
                                                  ++fn->arg_begin ());
       builder.CreateRet (ret);
-
-      jit_function::overload overload (fn, true, any, any, any);
-      for (octave_idx_type i = 0; i < next_id; ++i)
-        binary_ops[op].add_overload (overload);
+      binary_ops[op].add_overload (fn, true, true, any, any, any);
     }
 
   llvm::Type *void_t = llvm::Type::getVoidTy (context);
@@ -635,6 +638,12 @@
   return identities[id];
 }
 
+llvm::Value *
+jit_typeinfo::do_insert_error_check (void)
+{
+  return builder.CreateLoad (lerror_state);
+}
+
 jit_type *
 jit_typeinfo::do_type_of (const octave_value &ov) const
 {
@@ -679,10 +688,7 @@
     {
       jit_instruction *user = use_head->user ();
       size_t idx = use_head->index ();
-      if (idx < user->argument_count ())
-        user->stash_argument (idx, value);
-      else
-        user->stash_tag (0);
+      user->stash_argument (idx, value);
     }
 }
 
@@ -710,20 +716,6 @@
     mparent->remove (mlocation);
 }
 
-void
-jit_instruction::push_variable (void)
-{
-  if (tag ())
-    tag ()->push (this);
-}
-
-void
-jit_instruction::pop_variable (void)
-{
-  if (tag ())
-    tag ()->pop ();
-}
-
 llvm::BasicBlock *
 jit_instruction::parent_llvm (void) const
 {
@@ -735,24 +727,7 @@
 {
   if (type ())
     jit_print (os, type ()) << ": ";
-
-  if (tag ())
-    os << tag ()->name () << "." << id;
-  else
-    os << "#" << id;
-  return os;
-}
-
-jit_variable *
-jit_instruction::tag (void) const
-{
-  return reinterpret_cast<jit_variable *> (mtag.value ());
-}
-
-void
-jit_instruction::stash_tag (jit_variable *atag)
-{
-  mtag.stash_value (atag, this);
+  return os << "#" << mid;
 }
 
 // -------------------- jit_block --------------------
@@ -967,13 +942,25 @@
   for (size_t i = 0; i < pred_count (); ++i)
     changed = pred (i)->update_idom (visit_count) || changed;
 
+  if (! idom)
+    {
+      // one of our predecessors may have an idom of us, so if idom_intersect
+      // is called we need to have an idom. Assign idom to the pred with the
+      // lowest rpo id, as this prevents an infinite loop in idom_intersect
+      // FIXME: Textbook algorithm doesn't do this, ensure this is correct
+      size_t lowest_rpo = 0;
+      for (size_t i = 1; i < pred_count (); ++i)
+        if (pred (i)->id () < pred (lowest_rpo)->id ())
+          lowest_rpo = i;
+      idom = pred (lowest_rpo);
+      changed = true;
+    }
+
   jit_block *new_idom = pred (0);
   for (size_t i = 1; i < pred_count (); ++i)
     {
       jit_block *pidom = pred (i)->idom;
-      if (! new_idom)
-        new_idom = pidom;
-      else if (pidom)
+      if (pidom)
         new_idom = pidom->idom_intersect (new_idom);
     }
 
@@ -1077,6 +1064,7 @@
   jit_instruction::reset_ids ();
 
   entry_block = create<jit_block> ("body");
+  final_block = create<jit_block> ("final");
   blocks.push_back (entry_block);
   block = entry_block;
   visit (tee);
@@ -1086,7 +1074,9 @@
   assert (breaks.empty ());
   assert (continues.empty ());
 
-  jit_block *final_block = block;
+  block->append (create<jit_break> (final_block));
+  blocks.push_back (final_block);
+  
   for (vmap_t::iterator iter = vmap.begin (); iter != vmap.end (); ++iter)
        
     {
@@ -1096,9 +1086,7 @@
         final_block->append (create<jit_store_argument> (var));
     }
 
-  print_blocks ("octave jit ir");
-
-  construct_ssa (final_block);
+  construct_ssa ();
 
   // initialize the worklist to instructions derived from constants
   for (std::list<jit_value *>::iterator iter = constants.begin ();
@@ -1176,6 +1164,11 @@
 
   const jit_function& fn = jit_typeinfo::binary_op (be.op_type ());
   result = block->append (create<jit_call> (fn, lhsv, rhsv));
+
+  jit_block *normal = create<jit_block> (block->name () + "a");
+  block->append (create<jit_check_error> (normal, final_block));
+  blocks.push_back (normal);
+  block = normal;
 }
 
 void
@@ -1241,10 +1234,9 @@
 void
 jit_convert::visit_simple_for_command (tree_simple_for_command& cmd)
 {
-  // how a for statement is compiled. Note we do an initial check
-  // to see if the loop will run atleast once. This allows us to get
-  // better type inference bounds on variables defined and used only
-  // inside the for loop (e.g. the index variable)
+  // Note we do an initial check to see if the loop will run atleast once.
+  // This allows us to get better type inference bounds on variables defined
+  // and used only inside the for loop (e.g. the index variable)
 
   // If we are a nested for loop we need to store the previous breaks
   assert (! breaking);
@@ -1275,8 +1267,8 @@
   // do control expression, iter init, and condition check in prev_block (block)
   jit_value *control = visit (cmd.control_expr ());
   jit_call *init_iter = create<jit_call> (jit_typeinfo::for_init, control);
-  init_iter->stash_tag (iterator);
   block->append (init_iter);
+  block->append (create<jit_assign> (iterator, init_iter));
   
   jit_value *check = block->append (create<jit_call> (jit_typeinfo::for_check,
                                                       control, iterator));
@@ -1316,8 +1308,8 @@
   block->append (one);
 
   jit_call *iter_inc = create<jit_call> (add_fn, iterator, one);
-  iter_inc->stash_tag (iterator);
   block->append (iter_inc);
+  block->append (create<jit_assign> (iterator, iter_inc));
   check = block->append (create<jit_call> (jit_typeinfo::for_check, control,
                                            iterator));
   block->append (create<jit_cond_break> (check, body, tail));
@@ -1389,41 +1381,6 @@
 void
 jit_convert::visit_if_command_list (tree_if_command_list& lst)
 {
-  // Example code:
-  // if a == 1
-  //  c = c + 1;
-  // elseif b == 1
-  //  c = c + 2;
-  // else
-  //  c = c + 3;
-  // endif
-
-  // ********************
-  // FIXME: Documentation no longer reflects current version
-  // ********************
-
-  // Generates:
-  // prev_block0: % pred - ?
-  //   #temp.0 = call binary== (a.0, 1)
-  //   cond_break #temp.0, if_body1, ifelse_cond2
-  // if_body1:
-  //   c.1 = call binary+ (c.0, 1)
-  //   break if_tail5
-  // ifelse_cond2:
-  //   #temp.1 = call binary== (b.0, 1)
-  //   cond_break #temp.1, ifelse_body3, else4
-  // ifelse_body3:
-  //   c.2 = call binary+ (c.0, 2)
-  //   break if_tail5
-  // else4:
-  //   c.3 = call binary+ (c.0, 3)
-  //   break if_tail5
-  // if_tail5:
-  //   c.4 = phi | if_body1 -> c.1
-  //             | ifelse_body3 -> c.2
-  //             | else4 -> c.3
-
-
   tree_if_clause *last = lst.back ();
   size_t last_else = static_cast<size_t> (last->is_else_clause ());
 
@@ -1718,7 +1675,7 @@
                         bool print)
 {
   jit_variable *var = get_variable (lhs);
-  rhs->stash_tag (var);
+  block->append (create<jit_assign> (var, rhs));
 
   if (print)
     {
@@ -1742,7 +1699,7 @@
 }
 
 void
-jit_convert::construct_ssa (jit_block *final_block)
+jit_convert::construct_ssa (void)
 {
   final_block->label ();
   entry_block->compute_idom (final_block);
@@ -1784,6 +1741,7 @@
     }
 
   entry_block->visit_dom (&jit_convert::do_construct_ssa, &jit_block::pop_all);
+  print_dom ();
 }
 
 void
@@ -1795,7 +1753,8 @@
       jit_instruction *instr = *iter;
       if (! isa<jit_phi> (instr))
         {
-          for (size_t i = 0; i < instr->argument_count (); ++i)
+          for (size_t i = isa<jit_assign> (instr); i < instr->argument_count ();
+               ++i)
             {
               jit_value *arg = instr->argument (i);
               jit_variable *var = dynamic_cast<jit_variable *> (arg);
@@ -1814,11 +1773,22 @@
       size_t pred_idx = finish->pred_index (&block);
 
       for (jit_block::iterator iter = finish->begin (); iter != finish->end ()
-             && isa<jit_phi> (*iter); ++iter)
+             && isa<jit_phi> (*iter);)
         {
-          jit_instruction *phi = *iter;
-          jit_variable *var = phi->tag ();
-          phi->stash_argument (pred_idx, var->top ());
+          jit_phi *phi = dynamic_cast<jit_phi *> (*iter);
+          jit_variable *var = phi->dest ();
+          if (var->has_top ())
+            {
+              phi->stash_argument (pred_idx, var->top ());
+              ++iter;
+            }
+          else
+            {
+              // temporaries may have extranious phi nodes which can be removed
+              assert (! phi->use_count ());
+              assert (var->name ().size () && var->name ()[0] == '#');
+              iter = finish->remove (iter);
+            }
         }
     }
 }
@@ -1826,7 +1796,7 @@
 void
 jit_convert::place_releases (void)
 {
-  jit_convert::release_placer placer (*this);
+  release_placer placer (*this);
   entry_block->visit_dom (placer, &jit_block::pop_all);
 }
 
@@ -1848,24 +1818,22 @@
   for (jit_block::iterator iter = block.begin (); iter != block.end (); ++iter)
     {
       jit_instruction *instr = *iter;
+      instr->stash_last_use (instr);
+
       for (size_t i = 0; i < instr->argument_count (); ++i)
         {
-          jit_value *varg = instr->argument (i);
-          jit_instruction *arg = dynamic_cast<jit_instruction *> (varg);
-          if (arg && arg->tag ())
-            {
-              jit_variable *tag = arg->tag ();
-              tag->stash_last_use (instr);
-            }
+          jit_value *arg = instr->argument (i);
+          assert (arg);
+          arg->stash_last_use (instr);
         }
 
-      jit_variable *tag = instr->tag ();
-      if (tag && ! (isa<jit_phi> (instr) || isa<jit_store_argument> (instr))
-          && tag->has_top ())
+      jit_assign *assign = dynamic_cast<jit_assign *> (instr);
+      if (assign && assign->dest ()->has_top ())
         {
-          jit_instruction *last_use = tag->last_use ();
+          jit_variable *var = assign->dest ();
+          jit_instruction *last_use = var->last_use ();
           jit_call *release = convert.create<jit_call> (jit_typeinfo::release,
-                                                        tag->top ());
+                                                        var->top ());
           release->infer ();
           if (last_use && last_use->parent () == &block
               && ! isa<jit_phi> (last_use))
@@ -1953,7 +1921,7 @@
   jit_block *pblock = phi->parent ();
   llvm::PHINode *llvm_phi = llvm::cast<llvm::PHINode> (phi->to_llvm ());
 
-  bool can_remove = llvm_phi->use_empty ();
+  bool can_remove = ! phi->use_count ();
   if (! can_remove && llvm_phi->hasOneUse () && phi->use_count () == 1)
     {
       jit_instruction *user = phi->first_use ()->user ();
@@ -2000,9 +1968,7 @@
         {
           llvm::BasicBlock *pred = pblock->pred_llvm (i);
           if (phi->argument_type (i) == phi->type ())
-            {
-              llvm_phi->addIncoming (phi->argument_llvm (i), pred);
-            }
+            llvm_phi->addIncoming (phi->argument_llvm (i), pred);
           else
             {
               // add cast right before pred terminator
@@ -2152,6 +2118,19 @@
   fail ("ERROR: SSA construction should remove all variables");
 }
 
+void
+jit_convert::convert_llvm::visit (jit_check_error& check)
+{
+  llvm::Value *cond = jit_typeinfo::insert_error_check ();
+  llvm::Value *br = builder.CreateCondBr (cond, check.sucessor_llvm (1),
+                                          check.sucessor_llvm (0));
+  check.stash_llvm (br);
+}
+
+void
+jit_convert::convert_llvm::visit (jit_assign&)
+{}
+
 // -------------------- tree_jit --------------------
 
 tree_jit::tree_jit (void) : module (0), engine (0)
diff --git a/src/pt-jit.h b/src/pt-jit.h
--- a/src/pt-jit.h
+++ b/src/pt-jit.h
@@ -84,6 +84,7 @@
   class LLVMContext;
   class Type;
   class Twine;
+  class GlobalVariable;
 }
 
 class octave_base_value;
@@ -356,6 +357,11 @@
   {
     return instance->do_cast (to, from);
   }
+
+  static llvm::Value *insert_error_check (void)
+  {
+    return instance->do_insert_error_check ();
+  }
 private:
   jit_typeinfo (llvm::Module *m, llvm::ExecutionEngine *e);
 
@@ -487,6 +493,8 @@
 
   llvm::Function *create_identity (jit_type *type);
 
+  llvm::Value *do_insert_error_check (void);
+
   static jit_typeinfo *instance;
 
   llvm::Module *module;
@@ -494,6 +502,7 @@
   int next_id;
 
   llvm::Type *ov_t;
+  llvm::GlobalVariable *lerror_state;
 
   std::vector<jit_type*> id_to_type;
   jit_type *any;
@@ -525,19 +534,21 @@
 // We convert the octave parse tree to this IR directly.
 
 #define JIT_VISIT_IR_NOTEMPLATE                 \
-  JIT_METH(block)                               \
-  JIT_METH(break)                               \
-  JIT_METH(cond_break)                          \
-  JIT_METH(call)                                \
-  JIT_METH(extract_argument)                    \
-  JIT_METH(store_argument)                      \
-  JIT_METH(phi)                                 \
-  JIT_METH(variable)
+  JIT_METH(block);                              \
+  JIT_METH(break);                              \
+  JIT_METH(cond_break);                         \
+  JIT_METH(call);                               \
+  JIT_METH(extract_argument);                   \
+  JIT_METH(store_argument);                     \
+  JIT_METH(phi);                                \
+  JIT_METH(variable);                           \
+  JIT_METH(check_error);                        \
+  JIT_METH(assign)
 
 #define JIT_VISIT_IR_CONST                      \
-  JIT_METH(const_scalar)                        \
-  JIT_METH(const_index)                         \
-  JIT_METH(const_string)                        \
+  JIT_METH(const_scalar);                       \
+  JIT_METH(const_index);                        \
+  JIT_METH(const_string);                       \
   JIT_METH(const_range)
 
 #define JIT_VISIT_IR_CLASSES                    \
@@ -576,7 +587,8 @@
 {
   friend class jit_use;
 public:
-  jit_value (void) : llvm_value (0), ty (0), use_head (0), myuse_count (0) {}
+  jit_value (void) : llvm_value (0), ty (0), use_head (0), myuse_count (0),
+                     mlast_use (0) {}
 
   virtual ~jit_value (void);
 
@@ -608,6 +620,13 @@
     return ss.str ();
   }
 
+  jit_instruction *last_use (void) const { return mlast_use; }
+
+  void stash_last_use (jit_instruction *alast_use)
+  {
+    mlast_use = alast_use;
+  }
+
   virtual std::ostream& print (std::ostream& os, size_t indent = 0) const = 0;
 
   virtual std::ostream& short_print (std::ostream& os) const
@@ -644,6 +663,7 @@
   jit_type *ty;
   jit_use *use_head;
   size_t myuse_count;
+  jit_instruction *mlast_use;
 };
 
 std::ostream& operator<< (std::ostream& os, const jit_value& value);
@@ -737,12 +757,12 @@
 {
 public:
   // FIXME: this code could be so much pretier with varadic templates...
-  jit_instruction (void) : id (next_id ()), mparent (0)
+  jit_instruction (void) : mid (next_id ()), mparent (0)
   {}
 
   jit_instruction (size_t nargs, jit_value *adefault = 0)
   : already_infered (nargs, reinterpret_cast<jit_type *>(0)), arguments (nargs),
-    id (next_id ()), mparent (0)
+    mid (next_id ()), mparent (0)
   {
     if (adefault)
       for (size_t i = 0; i < nargs; ++i)
@@ -751,14 +771,14 @@
 
   jit_instruction (jit_value *arg0)
     : already_infered (1, reinterpret_cast<jit_type *>(0)), arguments (1), 
-      id (next_id ()), mparent (0)
+      mid (next_id ()), mparent (0)
   {
     stash_argument (0, arg0);
   }
 
   jit_instruction (jit_value *arg0, jit_value *arg1)
     : already_infered (2, reinterpret_cast<jit_type *>(0)), arguments (2), 
-      id (next_id ()), mparent (0)
+      mid (next_id ()), mparent (0)
   {
     stash_argument (0, arg0);
     stash_argument (1, arg1);
@@ -766,7 +786,7 @@
 
   jit_instruction (jit_value *arg0, jit_value *arg1, jit_value *arg2)
     : already_infered (3, reinterpret_cast<jit_type *>(0)), arguments (3), 
-      id (next_id ()), mparent (0)
+      mid (next_id ()), mparent (0)
   {
     stash_argument (0, arg0);
     stash_argument (1, arg1);
@@ -776,7 +796,7 @@
   jit_instruction (jit_value *arg0, jit_value *arg1, jit_value *arg2,
                    jit_value *arg3)
     : already_infered (3, reinterpret_cast<jit_type *>(0)), arguments (4), 
-      id (next_id ()), mparent (0)
+      mid (next_id ()), mparent (0)
   {
     stash_argument (0, arg0);
     stash_argument (1, arg1);
@@ -847,14 +867,14 @@
 
   virtual bool almost_dead (void) const { return false; }
 
+  virtual void push_variable (void) {}
+
+  virtual void pop_variable (void) {}
+
   virtual bool infer (void) { return false; }
 
   void remove (void);
 
-  void push_variable (void);
-
-  void pop_variable (void);
-
   virtual std::ostream& short_print (std::ostream& os) const;
 
   jit_block *parent (void) const { return mparent; }
@@ -873,9 +893,7 @@
     mlocation = alocation;
   }
 
-  jit_variable *tag (void) const;
-
-  void stash_tag (jit_variable *atag);
+  size_t id (void) const { return mid; }
 protected:
   std::vector<jit_type *> already_infered;
 private:
@@ -890,9 +908,7 @@
 
   std::vector<jit_use> arguments;
 
-  jit_use mtag;
-
-  size_t id;
+  size_t mid;
   jit_block *mparent;
   std::list<jit_instruction *>::iterator mlocation;
 };
@@ -960,11 +976,12 @@
 
   jit_instruction *insert_after (iterator loc, jit_instruction *instr);
 
-  void remove (jit_block::iterator iter)
+  iterator remove (iterator iter)
   {
     jit_instruction *instr = *iter;
-    instructions.erase (iter);
+    iter = instructions.erase (iter);
     instr->stash_parent (0, instructions.end ());
+    return iter;
   }
 
   jit_terminator *terminator (void) const;
@@ -1046,8 +1063,7 @@
     for (size_t i = 0; i < pred_count (); ++i)
       pred (i)->label (visit_count, number);
 
-    mid = number;
-    ++number;
+    mid = number++;
   }
 
   // See for idom computation algorithm
@@ -1254,15 +1270,66 @@
 };
 
 class
-jit_phi : public jit_instruction
+jit_assign_base : public jit_instruction
+{
+public:
+  jit_assign_base (jit_variable *adest) : jit_instruction (), mdest (adest) {}
+
+  jit_assign_base (jit_variable *adest, size_t npred) : jit_instruction (npred),
+                                                        mdest (adest) {}
+
+  jit_assign_base (jit_variable *adest, jit_value *arg0, jit_value *arg1)
+    : jit_instruction (arg0, arg1), mdest (adest) {}
+
+  jit_variable *dest (void) const { return mdest; }
+
+  virtual void push_variable (void)
+  {
+    mdest->push (this);
+  }
+
+  virtual void pop_variable (void)
+  {
+    mdest->pop ();
+  }
+private:
+  jit_variable *mdest;
+};
+
+class
+jit_assign : public jit_assign_base
 {
 public:
-  jit_phi (jit_variable *avariable, size_t npred)
-    : jit_instruction (npred)
+  jit_assign (jit_variable *adest, jit_instruction *asrc)
+    : jit_assign_base (adest, adest, asrc) {}
+
+  jit_instruction *src (void) const
+  {
+    return static_cast<jit_instruction *> (argument (1));
+  }
+
+  virtual void push_variable (void)
+  {
+    dest ()->push (src ());
+  }
+
+  virtual std::ostream& print (std::ostream& os, size_t indent = 0) const
   {
-    stash_tag (avariable);
+    return print_indent (os, indent) << *dest () << " = " << *src ();
   }
 
+  JIT_VALUE_ACCEPT (assign);
+private:
+  jit_variable *mdest;
+};
+
+class
+jit_phi : public jit_assign_base
+{
+public:
+  jit_phi (jit_variable *adest, size_t npred) : jit_assign_base (adest, npred)
+  {}
+
   virtual bool dead (void) const
   {
     return use_count () == 0;
@@ -1314,6 +1381,15 @@
     return os;
   }
 
+  virtual std::ostream& short_print (std::ostream& os) const
+  {
+    if (type ())
+      jit_print (os, type ()) << ": ";
+
+    dest ()->short_print (os);
+    return os << "#" << id ();
+  }
+
   JIT_VALUE_ACCEPT (phi);
 };
 
@@ -1323,6 +1399,9 @@
 public:
   jit_terminator (jit_value *arg0) : jit_instruction (arg0) {}
 
+  jit_terminator (jit_value *arg0, jit_value *arg1)
+    : jit_instruction (arg0, arg1) {}
+
   jit_terminator (jit_value *arg0, jit_value *arg1, jit_value *arg2)
     : jit_instruction (arg0, arg1, arg2) {}
 
@@ -1451,7 +1530,7 @@
   {
     print_indent (os, indent);
 
-    if (use_count () || tag ())
+    if (use_count ())
       short_print (os) << " = ";
     os << "call " << mfunction.name () << " (";
 
@@ -1475,20 +1554,46 @@
   const jit_function& mfunction;
 };
 
+// FIXME: This is just ugly...
+// checks error_state, if error_state is false then goto the normal branche,
+// otherwise goto the error branch
 class
-jit_extract_argument : public jit_instruction
+jit_check_error : public jit_terminator
 {
 public:
-  jit_extract_argument (jit_type *atype, jit_variable *var)
-    : jit_instruction ()
+  jit_check_error (jit_block *normal, jit_block *error)
+    : jit_terminator (normal, error) {}
+
+  jit_block *sucessor (size_t idx) const
+  {
+    return static_cast<jit_block *> (argument (idx));
+  }
+
+  size_t sucessor_count (void) const { return 2; }
+
+  virtual std::ostream& print (std::ostream& os, size_t indent = 0) const
+  {
+    print_indent (os, indent) << "check_error: normal: ";
+    print_sucessor (os, 0) << " error: ";
+    return print_sucessor (os, 1);
+  }
+
+  JIT_VALUE_ACCEPT (jit_check_error)
+};
+
+class
+jit_extract_argument : public jit_assign_base
+{
+public:
+  jit_extract_argument (jit_type *atype, jit_variable *adest)
+    : jit_assign_base (adest)
   {
     stash_type (atype);
-    stash_tag (var);
   }
 
   const std::string& name (void) const
   {
-    return tag ()->name ();
+    return dest ()->name ();
   }
 
   const jit_function::overload& overload (void) const
@@ -1512,14 +1617,12 @@
 {
 public:
   jit_store_argument (jit_variable *var)
-    : jit_instruction (var)
-  {
-    stash_tag (var);
-  }
+  : jit_instruction (var), dest (var)
+  {}
 
   const std::string& name (void) const
   {
-    return tag ()->name ();
+    return dest->name ();
   }
 
   const jit_function::overload& overload (void) const
@@ -1546,11 +1649,20 @@
   {
     jit_value *res = result ();
     print_indent (os, indent) << "store ";
-    short_print (os) << " = ";
-    return res->short_print (os);
+    dest->short_print (os);
+
+    if (! isa<jit_variable> (res))
+      {
+        os << " = ";
+        res->short_print (os);
+      }
+
+    return os;
   }
 
   JIT_VALUE_ACCEPT (store_argument)
+private:
+  jit_variable *dest;
 };
 
 class
@@ -1735,6 +1847,8 @@
 
   jit_block *entry_block;
 
+  jit_block *final_block;
+
   jit_block *block;
 
   llvm::Function *function;
@@ -1774,7 +1888,7 @@
     all_values.push_back (value);
   }
 
-  void construct_ssa (jit_block *final_block);
+  void construct_ssa (void);
 
   static void do_construct_ssa (jit_block& block);