src/share/vm/opto/parse2.cpp

rev 7387 : 8063137: Never-taken branches should be pruned when GWT LambdaForms are shared
Reviewed-by: ?

*** 35,44 ****
--- 35,45 ----
  #include "opto/divnode.hpp"
  #include "opto/idealGraphPrinter.hpp"
  #include "opto/matcher.hpp"
  #include "opto/memnode.hpp"
  #include "opto/mulnode.hpp"
+ #include "opto/opaquenode.hpp"
  #include "opto/parse.hpp"
  #include "opto/runtime.hpp"
  #include "runtime/deoptimization.hpp"
  #include "runtime/sharedRuntime.hpp"
  
*** 765,796 ****
  
  //--------------------------dynamic_branch_prediction--------------------------
  // Try to gather dynamic branch prediction behavior.  Return a probability
  // of the branch being taken and set the "cnt" field.  Returns a -1.0
  // if we need to use static prediction for some reason.
! float Parse::dynamic_branch_prediction(float &cnt) {
    ResourceMark rm;
  
    cnt  = COUNT_UNKNOWN;
  
    // Use MethodData information if it is available
    // FIXME: free the ProfileData structure
    ciMethodData* methodData = method()->method_data();
    if (!methodData->is_mature())  return PROB_UNKNOWN;
    ciProfileData* data = methodData->bci_to_data(bci());
    if (!data->is_JumpData())  return PROB_UNKNOWN;
  
    // get taken and not taken values
!   int     taken = data->as_JumpData()->taken();
!   int not_taken = 0;
    if (data->is_BranchData()) {
      not_taken = data->as_BranchData()->not_taken();
    }
  
    // scale the counts to be commensurate with invocation counts:
    taken = method()->scale_count(taken);
    not_taken = method()->scale_count(not_taken);
  
    // Give up if too few (or too many, in which case the sum will overflow) counts to be meaningful.
    // We also check that individual counters are positive first, overwise the sum can become positive.
    if (taken < 0 || not_taken < 0 || taken + not_taken < 40) {
      if (C->log() != NULL) {
--- 766,814 ----
  
  //--------------------------dynamic_branch_prediction--------------------------
  // Try to gather dynamic branch prediction behavior.  Return a probability
  // of the branch being taken and set the "cnt" field.  Returns a -1.0
  // if we need to use static prediction for some reason.
! float Parse::dynamic_branch_prediction(float &cnt, BoolTest::mask btest, Node* test) {
    ResourceMark rm;
  
    cnt  = COUNT_UNKNOWN;
  
+   int     taken = 0;
+   int not_taken = 0;
+ 
+   if (method()->ignore_profile()) {
+     if (btest == BoolTest::eq && test->is_Cmp() && test->in(1)->Opcode() == Op_Opaque4) {
+       Opaque4Node* opq = (Opaque4Node*)test->in(1);
+       taken = opq->taken();
+       not_taken = opq->not_taken();
+       opq->consume();
+     } else {
+       // No profile info. Be conservative.
+       int cnt = method()->interpreter_invocation_count();
+       taken = cnt / 2;
+       not_taken = cnt - taken;
+     }
+   } else {
      // Use MethodData information if it is available
      // FIXME: free the ProfileData structure
      ciMethodData* methodData = method()->method_data();
      if (!methodData->is_mature())  return PROB_UNKNOWN;
      ciProfileData* data = methodData->bci_to_data(bci());
      if (!data->is_JumpData())  return PROB_UNKNOWN;
  
      // get taken and not taken values
!     taken = data->as_JumpData()->taken();
!     not_taken = 0;
      if (data->is_BranchData()) {
        not_taken = data->as_BranchData()->not_taken();
      }
  
      // scale the counts to be commensurate with invocation counts:
      taken = method()->scale_count(taken);
      not_taken = method()->scale_count(not_taken);
+   }
  
    // Give up if too few (or too many, in which case the sum will overflow) counts to be meaningful.
    // We also check that individual counters are positive first, overwise the sum can become positive.
    if (taken < 0 || not_taken < 0 || taken + not_taken < 40) {
      if (C->log() != NULL) {
*** 839,850 ****
  }
  
  //-----------------------------branch_prediction-------------------------------
  float Parse::branch_prediction(float& cnt,
                                 BoolTest::mask btest,
!                                int target_bci) {
!   float prob = dynamic_branch_prediction(cnt);
    // If prob is unknown, switch to static prediction
    if (prob != PROB_UNKNOWN)  return prob;
  
    prob = PROB_FAIR;                   // Set default value
    if (btest == BoolTest::eq)          // Exactly equal test?
--- 857,869 ----
  }
  
  //-----------------------------branch_prediction-------------------------------
  float Parse::branch_prediction(float& cnt,
                                 BoolTest::mask btest,
!                                int target_bci,
!                                Node* test) {
!   float prob = dynamic_branch_prediction(cnt, btest, test);
    // If prob is unknown, switch to static prediction
    if (prob != PROB_UNKNOWN)  return prob;
  
    prob = PROB_FAIR;                   // Set default value
    if (btest == BoolTest::eq)          // Exactly equal test?
*** 930,940 ****
  
    Block* branch_block = successor_for_bci(target_bci);
    Block* next_block   = successor_for_bci(iter().next_bci());
  
    float cnt;
!   float prob = branch_prediction(cnt, btest, target_bci);
    if (prob == PROB_UNKNOWN) {
      // (An earlier version of do_ifnull omitted this trap for OSR methods.)
  #ifndef PRODUCT
      if (PrintOpto && Verbose)
        tty->print_cr("Never-taken edge stops compilation at bci %d",bci());
--- 949,959 ----
  
    Block* branch_block = successor_for_bci(target_bci);
    Block* next_block   = successor_for_bci(iter().next_bci());
  
    float cnt;
!   float prob = branch_prediction(cnt, btest, target_bci, c);
    if (prob == PROB_UNKNOWN) {
      // (An earlier version of do_ifnull omitted this trap for OSR methods.)
  #ifndef PRODUCT
      if (PrintOpto && Verbose)
        tty->print_cr("Never-taken edge stops compilation at bci %d",bci());
*** 1011,1021 ****
  
    Block* branch_block = successor_for_bci(target_bci);
    Block* next_block   = successor_for_bci(iter().next_bci());
  
    float cnt;
!   float prob = branch_prediction(cnt, btest, target_bci);
    float untaken_prob = 1.0 - prob;
  
    if (prob == PROB_UNKNOWN) {
  #ifndef PRODUCT
      if (PrintOpto && Verbose)
--- 1030,1040 ----
  
    Block* branch_block = successor_for_bci(target_bci);
    Block* next_block   = successor_for_bci(iter().next_bci());
  
    float cnt;
!   float prob = branch_prediction(cnt, btest, target_bci, c);
    float untaken_prob = 1.0 - prob;
  
    if (prob == PROB_UNKNOWN) {
  #ifndef PRODUCT
      if (PrintOpto && Verbose)