Use emplace() for associative containers.

* HACKING: Adjust requirements.  g++4.8 is now OK
for all our targets.
* iface/dve2/dve2.cc, src/dstarparse/dstarparse.yy
src/dstarparse/nsa2tgba.cc, src/graph/ngraph.hh,
src/ltlast/atomic_prop.cc, src/ltlast/binop.cc, src/ltlast/bunop.cc,
src/ltlast/multop.cc, src/ltlast/unop.cc, src/ltlvisit/mark.cc,
src/ltlvisit/relabel.cc, src/taalgos/emptinessta.cc,
src/taalgos/tgba2ta.cc, src/tgba/tgbaexplicit.hh, src/tgba/tgbagraph.hh,
src/tgba/tgbasafracomplement.cc, src/tgba/tgbatba.cc,
src/tgbaalgos/cycles.cc, src/tgbaalgos/degen.cc,
src/tgbaalgos/dtbasat.cc, src/tgbaalgos/dtgbasat.cc,
src/tgbaalgos/emptiness.cc, src/tgbaalgos/gtec/gtec.cc,
src/tgbaalgos/ltl2tgba_fm.cc, src/tgbaalgos/magic.cc,
src/tgbaalgos/ndfs_result.hxx, src/tgbaalgos/reachiter.cc,
src/tgbaalgos/scc.cc, src/tgbaalgos/sccfilter.cc, src/tgbaalgos/se05.cc,
src/tgbaalgos/simulation.cc, src/tgbaalgos/tau03.cc,
src/tgbaalgos/tau03opt.cc, src/tgbaalgos/weight.cc: Use emplace()
instead of insert(make_pair(...)) or insert(...::value_type(...)).

HACKING

@@ -229,25 +229,12 @@ C++11
 -----
 
   Spot uses some C++11 features, and therefore requires a C++11
-  compiler.  However (1) fully C++11-compliant compilers are
+  compiler.  The code relies on features that are not available in
-  not yet well deployed, and (2) development tools have yet
+  version of g++ older than 4.8, so this is our minimum requirement
-  to be updated to provide suitable C++11 support.  For instance
+  for now.  Avoid features that require 4.9.
-  Swig 2.0, which we use for the Python bindings, does not
-  understand C++11.  The upcoming release of Swig 3 has better
-  support for C++11, we should switch to it as soon as possible.
 
-  In the meantime, try to keep the C++11-specific syntax in the *.cc
+  Reasonably recent versions of clang should work as well.  Our
-  files as much as possible.
+  build farm has clang++ 3.5.
-
-  Use only C++11 features that are available in clang 3.1 and g++ 4.6:
-   - http://gcc.gnu.org/projects/cxx0x.html
-   - http://clang.llvm.org/cxx_status.html
-
-  Library interfaces that should not be used:
-   - emplace() is not implemented for associative containers
-     (std::map, std::set, and their unordered ffriends) is
-     before g++ 4.8.  Use
-       x.insert(std::make_pair(...)) instead of x.emplace(...)
 
 Encoding
 --------

iface/dve2/dve2.cc

@@ -353,9 +353,7 @@ namespace spot
 	{
 	  int enum_count = d->get_state_variable_type_value_count(i);
 	  for (int j = 0; j < enum_count; ++j)
-	    enum_map[i]
+	    enum_map[i].emplace(d->get_state_variable_type_value(i, j), j);
-	      .insert(std::make_pair(d->get_state_variable_type_value(i, j),
-				     j));
 	}
 
       for (ltl::atomic_prop_set::const_iterator ap = aps->begin();

src/dstarparse/dstarparse.yy

@@ -259,7 +259,7 @@ transitions:
   | transitions NUMBER opt_eols
   {
     std::pair<map_t::iterator, bool> i =
-      result.dest_map.insert(std::make_pair($2, *result.cur_guard));
+      result.dest_map.emplace($2, *result.cur_guard);
     if (!i.second)
       i.first->second |= *result.cur_guard;
     ++result.cur_guard;

src/dstarparse/nsa2tgba.cc

@@ -175,8 +175,7 @@ namespace spot
 	    build_state d(dlabel, pend);
             // Have we already seen this destination?
             int dest;
-	    std::pair<bs2num_map::iterator, bool> dres =
+	    auto dres = bs2num.emplace(d, 0);
-	      bs2num.insert(bs2num_map::value_type(d, 0));
             if (!dres.second)
               {
                 dest = dres.first->second;
@@ -199,8 +198,7 @@ namespace spot
 		build_state d(label(a, i->current_state()), pend);
 		// Have we already seen this destination?
 		int dest;
-		std::pair<bs2num_map::iterator, bool> dres =
+		auto dres = bs2num.emplace(d, 0);
-		  bs2num.insert(bs2num_map::value_type(d, 0));
 		if (!dres.second)
 		  {
 		    dest = dres.first->second;

src/graph/ngraph.hh

@@ -64,7 +64,7 @@ namespace spot
     template <typename... Args>
     state new_state(name n, Args&&... args)
     {
-      auto p = name_to_state.insert(std::make_pair(n, 0U));
+      auto p = name_to_state.emplace(n, 0U);
       if (p.second)
 	{
 	  unsigned s = g_.new_state(std::forward<Args>(args)...);
@@ -81,7 +81,7 @@ namespace spot
     /// \return true iff the newname was already used.
     bool alias_state(state s, name newname)
     {
-      return !name_to_state.insert(std::make_pair(newname, s)).second;
+      return !name_to_state.emplace(newname, s).second;
     }
 
     state get_state(name n) const

src/ltlast/atomic_prop.cc

@@ -91,7 +91,7 @@ namespace spot
     atomic_prop::instance(const std::string& name, environment& env)
     {
       const atomic_prop* ap;
-      auto ires = instances.insert(std::make_pair(key(name, &env), nullptr));
+      auto ires = instances.emplace(key(name, &env), nullptr);
       if (!ires.second)
 	ap = ires.first->second;
       else

src/ltlast/binop.cc

@@ -504,8 +504,7 @@ namespace spot
 	}
 
       const binop* res;
-      auto ires = instances.insert(std::make_pair(key(op, first, second),
+      auto ires = instances.emplace(key(op, first, second), nullptr);
-						  nullptr));
       if (!ires.second)
 	{
 	  // This instance already exists.

src/ltlast/bunop.cc

@@ -237,8 +237,7 @@ namespace spot
 	}
 
       const formula* res;
-      auto ires = instances.insert(std::make_pair(key(op, child, min, max),
+      auto ires = instances.emplace(key(op, child, min, max), nullptr);
-						  nullptr));
       if (!ires.second)
 	{
 	  // This instance already exists.

src/ltlast/multop.cc

@@ -595,7 +595,7 @@ namespace spot
       const multop* res;
       // Insert the key with the dummy nullptr just
       // to check if p already exists.
-      auto ires = instances.insert(std::make_pair(key(op, v), nullptr));
+      auto ires = instances.emplace(key(op, v), nullptr);
       if (!ires.second)
 	{
 	  // The instance did already exists.  Free v.

src/ltlast/unop.cc

@@ -300,7 +300,7 @@ namespace spot
 	}
 
       const unop* res;
-      auto ires = instances.insert(std::make_pair(key(op, child), nullptr));
+      auto ires = instances.emplace(key(op, child), nullptr);
       if (!ires.second)
 	{
 	  // This instance already exists.

src/ltlvisit/mark.cc

@@ -114,8 +114,7 @@ namespace spot
 			switch (bo->op())
 			  {
 			  case binop::EConcatMarked:
-			    empairs.insert(std::make_pair(bo->first(),
+			    empairs.emplace(bo->first(), bo->second());
-							  bo->second()));
 			    // fall through
 			  case binop::Xor:
 			  case binop::Implies:

src/ltlvisit/relabel.cc

@@ -110,8 +110,7 @@ namespace spot
 
 	const formula* rename(const formula* old)
 	{
-	  std::pair<map::iterator, bool> r =
+	  auto r = newname.emplace(old, nullptr);
-	    newname.insert(map::value_type(old, 0));
 	  if (!r.second)
 	    {
 	      return r.first->second->clone();
@@ -327,9 +326,7 @@ namespace spot
 	void
 	recurse(const formula* f)
 	{
-	  std::pair<fgraph::iterator, bool> i =
+	  auto i = g.emplace(f, succ_vec());
-	    g.insert(fgraph::value_type(f, succ_vec()));
-
 	  if (!s.empty())
 	    {
 	      const formula* top = s.top();
@@ -356,6 +353,10 @@ namespace spot
       {
 	unsigned num; // serial number, in pre-order
 	unsigned low; // lowest number accessible via unstacked descendants
+	data_entry(unsigned num = 0, unsigned low = 0)
+	  : num(num), low(low)
+	{
+	}
       };
       typedef std::unordered_map<const formula*, data_entry,
 				 const formula_ptr_hash> fmap_t;
@@ -410,9 +411,9 @@ namespace spot
 		// std::cerr << "  grand parent is "
 		// 	  << to_string(e.grand_parent)
 		// 	  << "\n  child is " << to_string(child) << '\n';
-		data_entry d = { num, num };
+		auto i = data.emplace(std::piecewise_construct,
-		std::pair<fmap_t::iterator, bool> i =
+				      std::forward_as_tuple(child),
-		  data.insert(fmap_t::value_type(child, d));
+				      std::forward_as_tuple(num, num));
 		if (i.second)	// New destination.
 		  {
 		    ++num;

src/taalgos/emptinessta.cc

@@ -106,7 +106,7 @@ namespace spot
         state_ta_product* init = new state_ta_product(
             (ta_init_it_->current_state()), kripke_init_state->clone());
 
-        if (!h.insert(std::make_pair(init, num + 1)).second)
+        if (!h.emplace(init, num + 1).second)
 	  {
 	    init->destroy();
 	    continue;
@@ -216,7 +216,7 @@ namespace spot
             // We do not need SUCC from now on.
 
             // Are we going to a new state?
-	    auto p = h.insert(std::make_pair(dest, num + 1));
+	    auto p = h.emplace(dest, num + 1);
             if (p.second)
               {
                 // Number it, stack it, and register its successors
@@ -427,7 +427,7 @@ namespace spot
             state* init = ta_init_it_.front();
             ta_init_it_.pop();
 
-	    if (!h.insert(std::make_pair(init, num + 1)).second)
+	    if (!h.emplace(init, num + 1).second)
 	      {
 		init->destroy();
 		continue;

src/taalgos/tgba2ta.cc

@@ -193,7 +193,7 @@ namespace spot
 	      down_cast<state_ta_explicit*> (init_set.top());
 	    init_set.pop();
 
-	    if (!h.insert(std::make_pair(init, num + 1)).second)
+	    if (!h.emplace(init, num + 1).second)
 	      {
 		init->destroy();
 		continue;

src/tgba/tgbaexplicit.hh

@@ -431,7 +431,7 @@ namespace spot
 		  last_dest = dest;
 		  dmi = dm.find(dest);
 		  if (dmi == dm.end())
-		    dmi = dm.insert(std::make_pair(dest, acc_map())).first;
+		    dmi = dm.emplace(dest, acc_map()).first;
 		}
 	      int acc = t1->acceptance_conditions.id();
 	      typename acc_map::iterator it = dmi->second.find(acc);
@@ -460,8 +460,7 @@ namespace spot
 	  if (j != alias_.end())
 	    return j->second;
 
-	  State* res =
+	  State* res = &(ls_.emplace(name, State(name)).first->second);
-	    &(ls_.insert(std::make_pair(name, State(name))).first->second);
 	  sl_[res] = name;
 	  // The first state we add is the initial state.
 	  // It can also be overridden with set_init_state().

src/tgba/tgbagraph.hh

@@ -386,7 +386,7 @@ namespace spot
 		}
 
 	      key_t k(t->dst, t->acc.id());
-	      auto p = trmap.insert(make_pair(k, t.trans()));
+	      auto p = trmap.emplace(k, t.trans());
 	      if (!p.second)
 		{
 		  // A previous transitions exist for k, merge the

src/tgba/tgbasafracomplement.cc

@@ -1184,8 +1184,8 @@ namespace spot
 							p.second, false);
 	    state_complement* s2 = new state_complement(e->clone(), e->clone(),
 							p.second, true);
-	    succ_list.insert(std::make_pair(p.first, s1));
+	    succ_list.emplace(p.first, s1);
-	    succ_list.insert(std::make_pair(p.first, s2));
+	    succ_list.emplace(p.first, s2);
 	  }
       }
     else
@@ -1210,7 +1210,7 @@ namespace spot
 	      {
 		st = new state_complement(e->clone(), e->clone(),
 					  p.second, true);
-		succ_list.insert(std::make_pair(p.first, st));
+		succ_list.emplace(p.first, st);
 	      }
 	    condition = the_acceptance_cond_;
 	  }
@@ -1219,7 +1219,7 @@ namespace spot
 	    for (auto& p: tr->second)
 	      {
 		st = new state_complement(newI, newJ, p.second, true);
-		succ_list.insert(std::make_pair(p.first, st));
+		succ_list.emplace(p.first, st);
 	      }
 	  }
 	delete newI;
@@ -1234,7 +1234,7 @@ namespace spot
 	  {
 	    st = new state_complement(pending->clone(), e->clone(),
 				      p.second, true);
-	    succ_list.insert(std::make_pair(p.first, st));
+	    succ_list.emplace(p.first, st);
 	  }
 	delete pending;
 

src/tgba/tgbatba.cc

@@ -315,8 +315,8 @@ namespace spot
 	    transmap_t::iterator id = transmap_.find(key);
 	    if (id == transmap_.end()) // No
 	      {
-		mapit_t pos = transmap_
+		mapit_t pos =
-		  .insert(std::make_pair(key, it->current_condition())).first;
+		  transmap_.emplace(key, it->current_condition()).first;
 		// Keep the order of the transitions in the
 		// degeneralized automaton related to the order of the
 		// transitions in the input automaton: in the past we

src/tgbaalgos/cycles.cc

@@ -66,8 +66,7 @@ namespace spot
   enumerate_cycles::tagged_state
   enumerate_cycles::tag_state(const state* s)
   {
-    std::pair<tagged_state, bool> p =
+    auto p = tags_.emplace(s, state_info());
-      tags_.insert(std::make_pair(s, state_info()));
     if (!p.second)
       s->destroy();
     return p.first;

src/tgbaalgos/degen.cc

@@ -103,7 +103,7 @@ namespace spot
             union_ |= set;
           }
         cache_entry e(common, union_);
-        return cache_.insert(std::make_pair(s, e)).first;
+        return cache_.emplace(s, e).first;
       }
 
       // Intersection of all outgoing acceptance sets
@@ -144,8 +144,7 @@ namespace spot
 
       bool check(const state* s)
       {
-	std::pair<cache_t::iterator, bool> p =
+	auto p = cache_.emplace(s, false);
-	  cache_.insert(std::make_pair(s, false));
 	if (p.second)
 	  {
 	    bdd all = a_->all_acceptance_conditions();
@@ -569,9 +568,7 @@ namespace spot
 
 		if (use_lvl_cache)
 		  {
-		    std::pair<lvl_cache_t::iterator, bool> res =
+		    auto res = lvl_cache.emplace(d.first, d.second);
-		      lvl_cache.insert(lvl_cache_t::value_type(d.first,
-							       d.second));
 
 		    if (!res.second)
 		      {

src/tgbaalgos/dtbasat.cc

@@ -312,10 +312,10 @@ namespace spot
 
 		    transition t(i, one, j);
 		    d.transid[t] = ++d.nvars;
-		    d.revtransid.insert(dict::rev_map::value_type(d.nvars, t));
+		    d.revtransid.emplace(d.nvars, t);
 		    int ta = d.transacc[t] =
 		      state_based_ ? transacc : ++d.nvars;
-		    d.revtransacc.insert(dict::rev_map::value_type(ta, t));
+		    d.revtransacc.emplace(ta, t);
 		  }
 	      }
 	  }

src/tgbaalgos/dtgbasat.cc

@@ -411,8 +411,7 @@ namespace spot
 
 		      transition t(i, one, j);
 		      d.transid[t] = ++d.nvars;
-		      d.revtransid.insert(dict::rev_map::
+		      d.revtransid.emplace(d.nvars, t);
-					  value_type(d.nvars, t));
 
 		      // Create the variable for the accepting transition
 		      // immediately afterwards.  It helps parsing the
@@ -421,8 +420,7 @@ namespace spot
 			{
 			  transition_acc ta(i, one, d.cand_acc[n], j);
 			  d.transaccid[ta] = ++d.nvars;
-			  d.revtransaccid.insert(dict::rev_acc_map::
+			  d.revtransaccid.emplace(d.nvars, ta);
-						 value_type(d.nvars, ta));
 			}
 		    }
 		}
@@ -443,8 +441,7 @@ namespace spot
 
 			  transition_acc ta(i, one, d.cand_acc[n], j);
 			  d.transaccid[ta] = d.nvars;
-			  d.revtransaccid.insert(dict::rev_acc_map::
+			  d.revtransaccid.emplace(d.nvars, ta);
-						 value_type(d.nvars, ta));
 			}
 		    }
 		}
@@ -459,8 +456,7 @@ namespace spot
 
 		      transition t(i, one, j);
 		      d.transid[t] = ++d.nvars;
-		      d.revtransid.insert(dict::rev_map::
+		      d.revtransid.emplace(d.nvars, t);
-					  value_type(d.nvars, t));
 		    }
 		}
 	  }

src/tgbaalgos/emptiness.cc

@@ -308,7 +308,7 @@ namespace spot
 
     assert(s->compare(i->s) == 0);
     src = res->new_state();
-    seen.insert(std::make_pair(i->s, src));
+    seen.emplace(i->s, src);
 
     for (; i != l->end();)
       {
@@ -355,7 +355,7 @@ namespace spot
 	s = the_next;
 
 
-	auto p = seen.insert(std::make_pair(next, 0));
+	auto p = seen.emplace(next, 0);
 	if (p.second)
 	  p.first->second = res->new_state();
 	dst = p.first->second;

src/tgbaalgos/gtec/gtec.cc

@@ -215,7 +215,7 @@ namespace spot
 	// We do not need SUCC from now on.
 
 	// Are we going to a new state?
-	auto p = ecs_->h.insert(std::make_pair(dest, num + 1));
+	auto p = ecs_->h.emplace(dest, num + 1);
 	if (p.second)
 	  {
 	    // Yes.  Bump number, stack the stack, and register its

src/tgbaalgos/ltl2tgba_fm.cc

@@ -1749,7 +1749,7 @@ namespace spot
 	}
 
       f->clone();
-      return ltl_bdd_.insert(std::make_pair(ff, t)).first->second;
+      return ltl_bdd_.emplace(ff, t).first->second;
     }
 
 
@@ -1974,7 +1974,7 @@ namespace spot
 	if (b2f_.find(t.symbolic) == b2f_.end())
 	  b2f_[t.symbolic] = f;
 
-	return f2b_.insert(std::make_pair(f->clone(), t)).first->second;
+	return f2b_.emplace(f->clone(), t).first->second;
       }
 
       const formula*

src/tgbaalgos/magic.cc

@@ -484,7 +484,7 @@ namespace spot
       void add_new_state(const state* s, color c)
         {
           assert(h.find(s) == h.end());
-          h.insert(std::make_pair(s, c));
+          h.emplace(s, c);
         }
 
       void pop_notify(const state*) const

src/tgbaalgos/ndfs_result.hxx

@@ -557,7 +557,7 @@ namespace spot
 	    {
 	      ndfsr_trace << a_->format_state(i->source) << " (-> "
 			  << a_->format_state(i->dest) << ") ";
-	      target.insert(std::make_pair(i->source, *i));
+	      target.emplace(i->source, *i);
 	    }
 	}
       ndfsr_trace << std::endl;
@@ -605,7 +605,7 @@ namespace spot
 		      << a_->format_state(begin) << std::endl;
 	  transition tmp;
 	  tmp.source = tmp.dest = 0; // Initialize to please GCC 4.0.1 (Darwin).
-	  target.insert(std::make_pair(begin, tmp));
+	  target.emplace(begin, tmp);
 	  min_path<true> s(this, a_, target, h_);
 	  const state* res = s.search(current.dest->clone(), run->cycle);
 	  assert(res);
@@ -623,7 +623,7 @@ namespace spot
       // Register all states from the cycle as target of the BFS.
       for (tgba_run::steps::const_iterator i = run->cycle.begin();
 	   i != run->cycle.end(); ++i)
-        target.insert(std::make_pair(i->s, tmp));
+        target.emplace(i->s, tmp);
 
       const state* prefix_start = a_->get_init_state();
       // There are two cases: either the initial state is already on

src/tgbaalgos/reachiter.cc

@@ -203,8 +203,7 @@ namespace spot
 	  }
 
 	dst = si->current_state();
-	std::pair<seen_map::iterator, bool> res =
+	auto res = seen.emplace(dst, n);
-	  seen.insert(std::make_pair(dst, n));
 	if (!res.second)
 	  {
 	    // The state has already been seen.

src/tgbaalgos/scc.cc

@@ -146,7 +146,7 @@ namespace spot
       self_loops_ = 0;
       state* init = aut_->get_init_state();
       num_ = -1;
-      h_.insert(std::make_pair(init, num_));
+      h_.emplace(init, num_);
       root_.emplace_front(num_);
       arc_acc_.push(bddfalse);
       arc_cond_.push(bddfalse);
@@ -196,7 +196,7 @@ namespace spot
 		// Record the transition between the SCC being popped
 		// and the previous SCC.
 		if (!root_.empty())
-		  root_.front().succ.insert(std::make_pair(num, cond));
+		  root_.front().succ.emplace(num, cond);
 	      }
 
 	    aut_->release_iter(succ);
@@ -223,7 +223,7 @@ namespace spot
 	  {
 	    // Yes.  Number it, stack it, and register its successors
 	    // for later processing.
-	    h_.insert(std::make_pair(dest, --num_));
+	    h_.emplace(dest, --num_);
 	    root_.emplace_front(num_);
 	    arc_acc_.push(acc);
 	    arc_cond_.push(cond);
@@ -244,7 +244,7 @@ namespace spot
 	    // dest SCC labelled with cond.
 	    succ_type::iterator i = root_.front().succ.find(dest);
 	    if (i == root_.front().succ.end())
-	      root_.front().succ.insert(std::make_pair(dest, cond));
+	      root_.front().succ.emplace(dest, cond);
 	    else
 	      i->second |= cond;
 

src/tgbaalgos/sccfilter.cc

@@ -466,7 +466,7 @@ namespace spot
 	// turn makes sure we preserve the acceptance condition
 	// ordering (which matters for degeneralization).
 	for (BDD c = useful.id(); c != 1; c = bdd_low(c))
-	  remap_table[n].insert(std::make_pair(bdd_var(c), --num));
+	  remap_table[n].emplace(bdd_var(c), --num);
 
 	max_table[n] = max_num;
       }
@@ -854,7 +854,7 @@ namespace spot
 	    // turn makes sure we preserve the acceptance condition
 	    // ordering (which matters for degeneralization).
 	    for (BDD c = useful.id(); c != 1; c = bdd_low(c))
-	      remap_table[n].insert(std::make_pair(bdd_var(c), --num));
+	      remap_table[n].emplace(bdd_var(c), --num);
 
 	    max_table[n] = max_num;
 	  }

src/tgbaalgos/se05.cc

@@ -470,7 +470,7 @@ namespace spot
                 int i = phc->erase(ps);
                 assert(i == 1);
                 (void)i;
-                ph->insert(std::make_pair(ps, c));
+                ph->emplace(ps, c);
               }
             else
               {
@@ -540,7 +540,7 @@ namespace spot
           if (c == CYAN)
             hc.insert(s);
           else
-            h.insert(std::make_pair(s, c));
+            h.emplace(s, c);
         }
 
       void pop_notify(const state*) const

src/tgbaalgos/simulation.cc

@@ -141,9 +141,9 @@ namespace spot
                     map_constraint& feed_me)
     {
       for (auto& p: list)
-	feed_me.insert(std::make_pair(std::make_pair(std::get<0>(p),
+	feed_me.emplace(std::make_pair(std::get<0>(p),
 				       std::get<1>(p)),
-				      std::get<2>(p)));
+			std::get<2>(p));
     }
 
 

src/tgbaalgos/tau03.cc

@@ -347,7 +347,7 @@ namespace spot
       void add_new_state(const state* s, color c)
         {
           assert(h.find(s) == h.end());
-          h.insert(std::make_pair(s, std::make_pair(c, bddfalse)));
+          h.emplace(s, std::make_pair(c, bddfalse));
         }
 
       void pop_notify(const state*) const

src/tgbaalgos/tau03opt.cc

@@ -445,7 +445,7 @@ namespace spot
               {
                 assert(c != CYAN);
                 std::pair<hash_type::iterator, bool> p;
-                p = ph->insert(std::make_pair(ps, std::make_pair(c, *acc)));
+                p = ph->emplace(ps, std::make_pair(c, *acc));
                 assert(p.second);
                 acc = &(p.first->second.second);
                 int i = phc->erase(ps);
@@ -536,7 +536,9 @@ namespace spot
           assert(hc.find(s) == hc.end() && h.find(s) == h.end());
           assert(c == CYAN);
           (void)c;
-          hc.insert(std::make_pair(s, std::make_pair(w, bddfalse)));
+          hc.emplace(std::piecewise_construct,
+		     std::forward_as_tuple(s),
+		     std::forward_as_tuple(w, bddfalse));
         }
 
       void pop_notify(const state*) const

src/tgbaalgos/weight.cc

@@ -39,7 +39,7 @@ namespace spot
         {
           weight::weight_vector::iterator it = pm->find(v);
           if (it == pm->end())
-            pm->insert(std::make_pair(v, 1));
+            pm->emplace(v, 1);
           else
             ++(it->second);
 	  break;