[JIT] Backport 8255120: C2: assert(outer->outcnt() >= phis + 2 && out…

…er->outcnt() <= phis + 2 + stores + 1) failed: only phis

src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp

@@ -45,6 +45,8 @@ bool ShenandoahBarrierC2Support::expand(Compile* C, PhaseIterGVN& igvn) {
   ShenandoahBarrierSetC2State* state = ShenandoahBarrierSetC2::bsc2()->state();
   if ((state->iu_barriers_count() +
        state->load_reference_barriers_count()) > 0) {
+    assert(C->post_loop_opts_phase(), "no loop opts allowed");
+    C->reset_post_loop_opts_phase(); // ... but we know what we are doing
     bool attempt_more_loopopts = ShenandoahLoopOptsAfterExpansion;
     C->clear_major_progress();
     PhaseIdealLoop ideal_loop(igvn, LoopOptsShenandoahExpand);
@@ -58,7 +60,10 @@ bool ShenandoahBarrierC2Support::expand(Compile* C, PhaseIterGVN& igvn) {
         return false;
       }
       C->clear_major_progress();
+
+      C->process_for_post_loop_opts_igvn(igvn);
     }
+    C->set_post_loop_opts_phase(); // now for real!
   }
   return true;
 }

src/hotspot/share/opto/compile.cpp

@@ -1989,16 +1989,21 @@ void Compile::remove_from_post_loop_opts_igvn(Node* n) {
 }
 
 void Compile::process_for_post_loop_opts_igvn(PhaseIterGVN& igvn) {
-  if (_for_post_loop_igvn.length() == 0) {
-    return; // no work to do
-  }
-  while (_for_post_loop_igvn.length() > 0) {
-    Node* n = _for_post_loop_igvn.pop();
-    n->remove_flag(Node::Flag_for_post_loop_opts_igvn);
-    igvn._worklist.push(n);
+  // Verify that all previous optimizations produced a valid graph
+  // at least to this point, even if no loop optimizations were done.
+  PhaseIdealLoop::verify(igvn);
+
+  C->set_post_loop_opts_phase(); // no more loop opts allowed
+
+  if (_for_post_loop_igvn.length() > 0) {
+    while (_for_post_loop_igvn.length() > 0) {
+      Node* n = _for_post_loop_igvn.pop();
+      n->remove_flag(Node::Flag_for_post_loop_opts_igvn);
+      igvn._worklist.push(n);
+    }
+    igvn.optimize();
+    assert(_for_post_loop_igvn.length() == 0, "no more delayed nodes allowed");
   }
-  igvn.optimize();
-  assert(_for_post_loop_igvn.length() == 0, "no more delayed nodes allowed");
 }
 
 // StringOpts and late inlining of string methods
@@ -2369,7 +2374,6 @@ void Compile::Optimize() {
     }
     if (!failing()) {
       // Verify that last round of loop opts produced a valid graph
-      TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
       PhaseIdealLoop::verify(igvn);
     }
   }
@@ -2405,15 +2409,9 @@ void Compile::Optimize() {
 
   if (failing())  return;
 
-  // Ensure that major progress is now clear
-  C->clear_major_progress();
+  C->clear_major_progress(); // ensure that major progress is now clear
 
-  {
-    // Verify that all previous optimizations produced a valid graph
-    // at least to this point, even if no loop optimizations were done.
-    TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
-    PhaseIdealLoop::verify(igvn);
-  }
+  process_for_post_loop_opts_igvn(igvn);
 
 #ifdef ASSERT
   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
@@ -2440,10 +2438,6 @@ void Compile::Optimize() {
   }
 #endif
 
-  C->set_post_loop_opts_phase(); // no more loop opts allowed
-
-  process_for_post_loop_opts_igvn(igvn);
-
   if (C->max_vector_size() > 0) {
     C->optimize_logic_cones(igvn);
     igvn.optimize();

src/hotspot/share/opto/compile.hpp

@@ -861,8 +861,9 @@ class Compile : public Phase {
   void remove_coarsened_lock(Node* n);
   bool coarsened_locks_consistent();
 
-  bool     post_loop_opts_phase() { return _post_loop_opts_phase; }
-  void set_post_loop_opts_phase() { _post_loop_opts_phase = true; }
+  bool       post_loop_opts_phase() { return _post_loop_opts_phase;  }
+  void   set_post_loop_opts_phase() { _post_loop_opts_phase = true;  }
+  void reset_post_loop_opts_phase() { _post_loop_opts_phase = false; }
 
   void record_for_post_loop_opts_igvn(Node* n);
   void remove_from_post_loop_opts_igvn(Node* n);

src/hotspot/share/opto/loopnode.hpp

@@ -1024,6 +1024,8 @@ class PhaseIdealLoop : public PhaseTransform {
   // is useful to verify that all inputs properly dominate their uses.
   static void verify(PhaseIterGVN& igvn) {
 #ifdef ASSERT
+    ResourceMark rm;
+    Compile::TracePhase tp("idealLoopVerify", &timers[_t_idealLoopVerify]);
     PhaseIdealLoop v(igvn);
 #endif
   }