8342941: IGV: Add various new graph dumps during loop opts

Reviewed-by: chagedorn, dlunden

Author: Saranya Natarajan

src/hotspot/share/opto/loopTransform.cpp

@@ -862,7 +862,7 @@ bool IdealLoopTree::policy_maximally_unroll(PhaseIdealLoop* phase) const {
 
   uint trip_count = cl->trip_count();
   // Note, max_juint is used to indicate unknown trip count.
-  assert(trip_count > 1, "one iteration loop should be optimized out already");
+  assert(trip_count > 1, "one-iteration loop should be optimized out already");
   assert(trip_count < max_juint, "exact trip_count should be less than max_juint.");
 
   // If nodes are depleted, some transform has miscalculated its needs.
@@ -1399,6 +1399,7 @@ void PhaseIdealLoop::insert_pre_post_loops(IdealLoopTree *loop, Node_List &old_n
   CountedLoopNode *post_head = nullptr;
   Node* post_incr = incr;
   Node* main_exit = insert_post_loop(loop, old_new, main_head, main_end, post_incr, limit, post_head);
+  C->print_method(PHASE_AFTER_POST_LOOP, 4, post_head);
 
   //------------------------------
   // Step B: Create Pre-Loop.
@@ -1613,8 +1614,10 @@ void PhaseIdealLoop::insert_vector_post_loop(IdealLoopTree *loop, Node_List &old
   Node *limit = main_end->limit();
 
   // In this case we throw away the result as we are not using it to connect anything else.
+  C->print_method(PHASE_BEFORE_POST_LOOP, 4, main_head);
   CountedLoopNode *post_head = nullptr;
   insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_head);
+  C->print_method(PHASE_AFTER_POST_LOOP, 4, post_head);
 
   // It's difficult to be precise about the trip-counts
   // for post loops.  They are usually very short,
@@ -3077,6 +3080,7 @@ bool IdealLoopTree::do_remove_empty_loop(PhaseIdealLoop *phase) {
       return false;
     }
   }
+  phase->C->print_method(PHASE_BEFORE_REMOVE_EMPTY_LOOP, 4, cl);
   if (cl->is_pre_loop()) {
     // If the loop we are removing is a pre-loop then the main and post loop
     // can be removed as well.
@@ -3179,6 +3183,7 @@ bool IdealLoopTree::do_remove_empty_loop(PhaseIdealLoop *phase) {
   phase->_igvn.replace_input_of(cl->loopexit(), CountedLoopEndNode::TestValue, zero);
 
   phase->C->set_major_progress();
+  phase->C->print_method(PHASE_AFTER_REMOVE_EMPTY_LOOP, 4, final_iv);
   return true;
 }
 
@@ -3314,7 +3319,7 @@ void IdealLoopTree::collect_loop_core_nodes(PhaseIdealLoop* phase, Unique_Node_L
 }
 
 //------------------------------do_one_iteration_loop--------------------------
-// Convert one iteration loop into normal code.
+// Convert one-iteration loop into normal code.
 bool IdealLoopTree::do_one_iteration_loop(PhaseIdealLoop *phase) {
   if (!_head->as_Loop()->is_valid_counted_loop(T_INT)) {
     return false; // Only for counted loop
@@ -3331,6 +3336,7 @@ bool IdealLoopTree::do_one_iteration_loop(PhaseIdealLoop *phase) {
   }
 #endif
 
+  phase->C->print_method(PHASE_BEFORE_ONE_ITERATION_LOOP, 4, cl);
   Node *init_n = cl->init_trip();
   // Loop boundaries should be constant since trip count is exact.
   assert((cl->stride_con() > 0 && init_n->get_int() + cl->stride_con() >= cl->limit()->get_int()) ||
@@ -3340,6 +3346,7 @@ bool IdealLoopTree::do_one_iteration_loop(PhaseIdealLoop *phase) {
   // and all loop-invariant uses of the exit values will be correct.
   phase->_igvn.replace_node(cl->phi(), cl->init_trip());
   phase->C->set_major_progress();
+  phase->C->print_method(PHASE_AFTER_ONE_ITERATION_LOOP, 4, init_n);
   return true;
 }
 
@@ -3354,7 +3361,7 @@ bool IdealLoopTree::iteration_split_impl(PhaseIdealLoop *phase, Node_List &old_n
   // Compute loop trip count if possible.
   compute_trip_count(phase);
 
-  // Convert one iteration loop into normal code.
+  // Convert one-iteration loop into normal code.
   if (do_one_iteration_loop(phase)) {
     return true;
   }

src/hotspot/share/opto/loopnode.hpp

@@ -742,7 +742,7 @@ class IdealLoopTree : public ResourceObj {
   // Micro-benchmark spamming.  Remove empty loops.
   bool do_remove_empty_loop( PhaseIdealLoop *phase );
 
-  // Convert one iteration loop into normal code.
+  // Convert one-iteration loop into normal code.
   bool do_one_iteration_loop( PhaseIdealLoop *phase );
 
   // Return TRUE or FALSE if the loop should be peeled or not. Peel if we can

src/hotspot/share/opto/loopopts.cpp

@@ -4338,6 +4338,7 @@ bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old
       }
     }
   }
+  C->print_method(PHASE_BEFORE_DUPLICATE_LOOP_BACKEDGE, 4, head);
 
   // Collect data nodes that need to be clones as well
   int dd = dom_depth(head);
@@ -4428,6 +4429,8 @@ bool PhaseIdealLoop::duplicate_loop_backedge(IdealLoopTree *loop, Node_List &old
 
   C->set_major_progress();
 
+  C->print_method(PHASE_AFTER_DUPLICATE_LOOP_BACKEDGE, 4, outer_head);
+
   return true;
 }
 

src/hotspot/share/opto/phasetype.hpp

@@ -75,6 +75,14 @@
   flags(ITER_GVN_AFTER_ELIMINATION,     "Iter GVN after Eliminating Allocations and Locks") \
   flags(BEFORE_PRE_MAIN_POST,           "Before Pre/Main/Post Loops") \
   flags(AFTER_PRE_MAIN_POST,            "After Pre/Main/Post Loops") \
+  flags(BEFORE_POST_LOOP,               "Before Post Loop") \
+  flags(AFTER_POST_LOOP,                "After Post Loop") \
+  flags(BEFORE_REMOVE_EMPTY_LOOP,       "Before Remove Empty Loop") \
+  flags(AFTER_REMOVE_EMPTY_LOOP,        "After Remove Empty Loop") \
+  flags(BEFORE_ONE_ITERATION_LOOP,      "Before Replace One-Iteration Loop") \
+  flags(AFTER_ONE_ITERATION_LOOP,       "After Replace One-Iteration Loop") \
+  flags(BEFORE_DUPLICATE_LOOP_BACKEDGE, "Before Duplicate Loop Backedge") \
+  flags(AFTER_DUPLICATE_LOOP_BACKEDGE,  "After Duplicate Loop Backedge") \
   flags(BEFORE_LOOP_UNROLLING,          "Before Loop Unrolling") \
   flags(AFTER_LOOP_UNROLLING,           "After Loop Unrolling") \
   flags(PHASEIDEALLOOP1,                "PhaseIdealLoop 1") \

test/hotspot/jtreg/compiler/lib/ir_framework/CompilePhase.java

@@ -86,6 +86,14 @@ public enum CompilePhase {
     ITER_GVN_AFTER_ELIMINATION(     "Iter GVN after Eliminating Allocations and Locks"),
     BEFORE_PRE_MAIN_POST(           "Before Pre/Main/Post Loops"),
     AFTER_PRE_MAIN_POST(            "After Pre/Main/Post Loops"),
+    BEFORE_POST_LOOP(               "Before Post Loop"),
+    AFTER_POST_LOOP(                "After Post Loop"),
+    BEFORE_REMOVE_EMPTY_LOOP(       "Before Remove Empty Loop"),
+    AFTER_REMOVE_EMPTY_LOOP(        "After Remove Empty Loop"),
+    BEFORE_ONE_ITERATION_LOOP(      "Before Replacing One-Iteration Loop"),
+    AFTER_ONE_ITERATION_LOOP(       "After Replacing One-Iteration Loop"),
+    BEFORE_DUPLICATE_LOOP_BACKEDGE( "Before Duplicate Loop Backedge"),
+    AFTER_DUPLICATE_LOOP_BACKEDGE(  "After Duplicate Loop Backedge"),
     PHASEIDEALLOOP1(                "PhaseIdealLoop 1"),
     PHASEIDEALLOOP2(                "PhaseIdealLoop 2"),
     PHASEIDEALLOOP3(                "PhaseIdealLoop 3"),

test/hotspot/jtreg/compiler/predicates/assertion/TestTemplateWithoutOpaqueLoopNodes.java

@@ -24,15 +24,15 @@
 /*
  * @test id=Xcomp
  * @bug 8333252
- * @summary Test that no Template Assertion Predicate is created in Loop Prediction for one iteration loop.
+ * @summary Test that no Template Assertion Predicate is created in Loop Prediction for one-iteration loop.
  * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,*TestTemplateWithoutOpaqueLoopNodes::test
  *                   compiler.predicates.assertion.TestTemplateWithoutOpaqueLoopNodes
  */
 
 /*
  * @test id=Xbatch
  * @bug 8333252
- * @summary Test that no Template Assertion Predicate is created in Loop Prediction for one iteration loop.
+ * @summary Test that no Template Assertion Predicate is created in Loop Prediction for one-iteration loop.
  * @run main/othervm -Xbatch -XX:CompileCommand=compileonly,*TestTemplateWithoutOpaqueLoopNodes::test
  *                   compiler.predicates.assertion.TestTemplateWithoutOpaqueLoopNodes
  */

test/hotspot/jtreg/compiler/splitif/TestSplitDivisionThroughPhi.java

@@ -140,7 +140,7 @@ static void testPushModLThruPhiForOuterLongLoop() {
    // the iv phi in one pass of Split If.
     static void testPushDivIThruPhiInChain() {
         for (int i = 10; i > 1; i -= 2) {
-            // Empty one iteration loop which is only removed after split if in first loop opts phase. This prevents
+            // Empty one-iteration loop which is only removed after split if in first loop opts phase. This prevents
             // that the Mul node is already split through the iv phi while the Div node cannot be split yet due to
             // the zero divisor check which can only be removed in the IGVN after the first loop opts pass.
             for (int j = 0; j < 1; j++) {