Index: lra-coalesce.c
===================================================================
--- lra-coalesce.c	(revision 198077)
+++ lra-coalesce.c	(working copy)
@@ -201,24 +201,14 @@ update_live_info (bitmap lr_bitmap)
     }
 }
 
-/* Return true if pseudo REGNO can be potentially coalesced.  Use
-   SPLIT_PSEUDO_BITMAP to find pseudos whose live ranges were
-   split.  */
+/* Return true if pseudo REGNO can be potentially coalesced.  */
 static bool
-coalescable_pseudo_p (int regno, bitmap split_origin_bitmap)
+coalescable_pseudo_p (int regno)
 {
   lra_assert (regno >= FIRST_PSEUDO_REGISTER);
-  /* Don't coalesce inheritance pseudos because spilled inheritance
-     pseudos will be removed in subsequent 'undo inheritance'
-     pass.  */
-  return (lra_reg_info[regno].restore_regno < 0
-	  /* We undo splits for spilled pseudos whose live ranges were
-	     split.  So don't coalesce them, it is not necessary and
-	     the undo transformations would be wrong.  */
-	  && ! bitmap_bit_p (split_origin_bitmap, regno)
-	  /* We don't want to coalesce regnos with equivalences, at
+  return (/* We don't want to coalesce regnos with equivalences, at
 	     least without updating this info.  */
-	  && ira_reg_equiv[regno].constant == NULL_RTX
+	  ira_reg_equiv[regno].constant == NULL_RTX
 	  && ira_reg_equiv[regno].memory == NULL_RTX
 	  && ira_reg_equiv[regno].invariant == NULL_RTX);
 }
@@ -230,12 +220,10 @@ lra_coalesce (void)
 {
   basic_block bb;
   rtx mv, set, insn, next, *sorted_moves;
-  int i, mv_num, sregno, dregno, restore_regno;
-  unsigned int regno;
+  int i, mv_num, sregno, dregno;
   int coalesced_moves;
   int max_regno = max_reg_num ();
-  bitmap_head involved_insns_bitmap, split_origin_bitmap;
-  bitmap_iterator bi;
+  bitmap_head involved_insns_bitmap;
 
   timevar_push (TV_LRA_COALESCE);
 
@@ -249,11 +237,6 @@ lra_coalesce (void)
     first_coalesced_pseudo[i] = next_coalesced_pseudo[i] = i;
   sorted_moves = XNEWVEC (rtx, get_max_uid ());
   mv_num = 0;
-  /* Collect pseudos whose live ranges were split.  */
-  bitmap_initialize (&split_origin_bitmap, &reg_obstack);
-  EXECUTE_IF_SET_IN_BITMAP (&lra_split_regs, 0, regno, bi)
-    if ((restore_regno = lra_reg_info[regno].restore_regno) >= 0)
-      bitmap_set_bit (&split_origin_bitmap, restore_regno);
   /* Collect moves.  */
   coalesced_moves = 0;
   FOR_EACH_BB (bb)
@@ -265,15 +248,13 @@ lra_coalesce (void)
 	    && (sregno = REGNO (SET_SRC (set))) >= FIRST_PSEUDO_REGISTER
 	    && (dregno = REGNO (SET_DEST (set))) >= FIRST_PSEUDO_REGISTER
 	    && mem_move_p (sregno, dregno)
-	    && coalescable_pseudo_p (sregno, &split_origin_bitmap)
-	    && coalescable_pseudo_p (dregno, &split_origin_bitmap)
+	    && coalescable_pseudo_p (sregno) && coalescable_pseudo_p (dregno)
 	    && ! side_effects_p (set)
 	    && !(lra_intersected_live_ranges_p
 		 (lra_reg_info[sregno].live_ranges,
 		  lra_reg_info[dregno].live_ranges)))
 	  sorted_moves[mv_num++] = insn;
     }
-  bitmap_clear (&split_origin_bitmap);
   qsort (sorted_moves, mv_num, sizeof (rtx), move_freq_compare_func);
   /* Coalesced copies, most frequently executed first.	*/
   bitmap_initialize (&coalesced_pseudos_bitmap, &reg_obstack);
Index: lra.c
===================================================================
--- lra.c	(revision 198077)
+++ lra.c	(working copy)
@@ -2295,11 +2295,20 @@ lra (FILE *f)
 	    lra_assign ();
 	  else
 	    {
-	      /* Do coalescing only for regular algorithms.  */
-	      if (! lra_assign () && lra_coalesce ())
-		live_p = false;
+	      bool spill_p = !lra_assign ();
+
 	      if (lra_undo_inheritance ())
 		live_p = false;
+	      if (spill_p)
+		{
+		  if (! live_p)
+		    {
+		      lra_create_live_ranges (true);
+		      live_p = true;
+		    }
+		  if (lra_coalesce ())
+		    live_p = false;
+		}
 	      if (! live_p)
 		lra_clear_live_ranges ();
 	    }
Index: testsuite/g++.dg/opt/pr56999.C
===================================================================
--- testsuite/g++.dg/opt/pr56999.C	(revision 0)
+++ testsuite/g++.dg/opt/pr56999.C	(working copy)
@@ -0,0 +1,188 @@
+// PR rtl-optimization/56999
+// { dg-do run }
+// { dg-options "-O2" }
+// { dg-additional-options "-fpic" { target fpic } }
+// { dg-additional-options "-march=i686 -mtune=atom" { target ia32 } }
+// { dg-require-visibility "" }
+
+extern "C" void abort (void);
+extern "C" void exit (int);
+volatile bool do_exit = true;
+struct JSScript;
+struct JITScript { int i; };
+#pragma GCC visibility push(hidden)
+typedef struct JSCompartment JSCompartment;
+typedef struct JSContext JSContext;
+namespace js
+{
+  struct ContextFriendFields
+  {
+    JSCompartment *compartment;
+  };
+  struct TempAllocPolicy
+  {
+  };
+  template <class T>
+  struct Vector
+  {
+    T *mBegin;
+    T *begin () { return mBegin; }
+    T & operator[] (unsigned i) { return begin ()[i]; }
+    template <class U>
+    __attribute__((noinline, noclone))
+    bool append (U) { asm volatile ("" : : : "memory"); if (do_exit) abort (); return false; }
+  };
+  namespace types
+  {
+    struct TypeCompartment;
+  }
+  namespace mjit
+  {
+  }
+  namespace ion
+  {
+    struct IonScript;
+  }
+  namespace types
+  {
+    struct CompilerOutput
+    {
+      enum Kind { MethodJIT, ParallelIon };
+      JSScript *script;
+      unsigned kindInt : 2;
+      bool constructing : 1;
+      bool barriers : 1;
+      bool pendingRecompilation : 1;
+      Kind kind () const { return static_cast <Kind> (kindInt); }
+      bool isValid () const;
+    };
+    struct RecompileInfo
+    {
+      unsigned outputIndex;
+      CompilerOutput *compilerOutput (TypeCompartment & types) const;
+      CompilerOutput *compilerOutput (JSContext *cx) const;
+    };
+    struct TypeCompartment
+    {
+      Vector <CompilerOutput> *constrainedOutputs;
+      Vector <RecompileInfo> *pendingRecompiles;
+      void addPendingRecompile (JSContext *cx, const RecompileInfo & info);
+    };
+  }
+}
+struct JSScript
+{
+  struct JITScriptHandle
+  {
+    static volatile JITScript *UNJITTABLE __attribute__((visibility ("default")));
+    JITScript *value;
+    bool isValid () { return value != UNJITTABLE; }
+    JITScript *getValid () { return value; }
+  };
+  struct JITScriptSet
+  {
+    JITScriptHandle jitHandleNormal, jitHandleNormalBarriered;
+    JITScriptHandle jitHandleCtor, jitHandleCtorBarriered;
+    JITScriptHandle jitNull1, jitNull2;
+  };
+  JITScriptSet *mJITInfo;
+  void *ion;
+  JITScriptHandle *jitHandle (bool constructing, bool barriers)
+  {
+    return constructing ? (barriers ? &mJITInfo->jitHandleCtorBarriered
+				    : &mJITInfo->jitHandleCtor)
+			: (barriers ? &mJITInfo->jitHandleNormalBarriered
+				    : &mJITInfo->jitHandleNormal);
+  }
+  JITScript *getJIT (bool constructing, bool barriers)
+  {
+    JITScriptHandle *jith = jitHandle (constructing, barriers);
+    return jith->isValid () ? jith->getValid () : __null;
+  }
+};
+struct JSContext : js::ContextFriendFields
+{
+};
+namespace js
+{
+  __attribute__((noinline, noclone))
+  void CancelOffThreadIonCompile (JSCompartment *, JSScript *)
+  {
+    if (do_exit)
+      exit (0);
+  }
+}
+struct JSCompartment
+{
+  js::types::TypeCompartment types;
+};
+namespace js
+{
+  namespace types
+  {
+    inline bool CompilerOutput::isValid () const
+    {
+      if (!script)
+	return false;
+      switch (kind ())
+	{
+	case MethodJIT:
+	  {
+	    JITScript *jit = script->getJIT (constructing, barriers);
+	    if (!jit)
+	      return false;
+	  }
+	case ParallelIon:
+	  return true;
+	}
+      return false;
+    }
+    inline CompilerOutput *RecompileInfo::compilerOutput (TypeCompartment & types) const
+    {
+      return &(*types.constrainedOutputs)[outputIndex];
+    }
+    inline CompilerOutput *RecompileInfo::compilerOutput (JSContext *cx) const
+    {
+      return compilerOutput (cx->compartment->types);
+    }
+  }
+}
+using namespace js::types;
+__attribute__((noinline, noclone)) void
+TypeCompartment::addPendingRecompile (JSContext *cx, const RecompileInfo & info)
+{
+  CompilerOutput *co = info.compilerOutput (cx);
+  if (co->pendingRecompilation)
+    if (co->isValid ())
+      CancelOffThreadIonCompile (cx->compartment, co->script);
+  if (co->isValid ())
+    pendingRecompiles->append (info);
+}
+volatile JITScript *JSScript::JITScriptHandle::UNJITTABLE;
+int
+main ()
+{
+  JSContext cx;
+  JSCompartment com;
+  RecompileInfo info;
+  cx.compartment = &com;
+  info.outputIndex = 0;
+  js::Vector<CompilerOutput> v;
+  JITScript js;
+  JSScript::JITScriptSet set;
+  __builtin_memset (&set, 0, sizeof set);
+  set.jitHandleCtor.value = &js;
+  JSScript s;
+  s.mJITInfo = &set;
+  CompilerOutput co;
+  co.kindInt = 0;
+  co.constructing = true;
+  co.barriers = false;
+  co.pendingRecompilation = true;
+  co.script = &s;
+  v.mBegin = &co;
+  com.types.constrainedOutputs = &v;
+  com.types.pendingRecompiles = __null;
+  com.types.addPendingRecompile (&cx, info);
+  abort ();
+}
