8358655: AArch64: Simplify Interpreter::profile_taken_branch

Author: chadrako

src/hotspot/cpu/aarch64/interp_masm_aarch64.cpp

@@ -1016,31 +1016,16 @@ void InterpreterMacroAssembler::update_mdp_for_ret(Register return_bci) {
 }
 
 
-void InterpreterMacroAssembler::profile_taken_branch(Register mdp,
-                                                     Register bumped_count) {
+void InterpreterMacroAssembler::profile_taken_branch(Register mdp) {
   if (ProfileInterpreter) {
     Label profile_continue;
 
     // If no method data exists, go to profile_continue.
-    // Otherwise, assign to mdp
     test_method_data_pointer(mdp, profile_continue);
 
     // We are taking a branch.  Increment the taken count.
-    // We inline increment_mdp_data_at to return bumped_count in a register
-    //increment_mdp_data_at(mdp, in_bytes(JumpData::taken_offset()));
-    Address data(mdp, in_bytes(JumpData::taken_offset()));
-    ldr(bumped_count, data);
-    assert(DataLayout::counter_increment == 1,
-            "flow-free idiom only works with 1");
-    // Intel does this to catch overflow
-    // addptr(bumped_count, DataLayout::counter_increment);
-    // sbbptr(bumped_count, 0);
-    // so we do this
-    adds(bumped_count, bumped_count, DataLayout::counter_increment);
-    Label L;
-    br(Assembler::CS, L);       // skip store if counter overflow
-    str(bumped_count, data);
-    bind(L);
+    increment_mdp_data_at(mdp, in_bytes(JumpData::taken_offset()));
+
     // The method data pointer needs to be updated to reflect the new target.
     update_mdp_by_offset(mdp, in_bytes(JumpData::displacement_offset()));
     bind(profile_continue);
@@ -1055,7 +1040,7 @@ void InterpreterMacroAssembler::profile_not_taken_branch(Register mdp) {
     // If no method data exists, go to profile_continue.
     test_method_data_pointer(mdp, profile_continue);
 
-    // We are taking a branch.  Increment the not taken count.
+    // We are not taking a branch.  Increment the not taken count.
     increment_mdp_data_at(mdp, in_bytes(BranchData::not_taken_offset()));
 
     // The method data pointer needs to be updated to correspond to

src/hotspot/cpu/aarch64/interp_masm_aarch64.hpp

@@ -276,7 +276,7 @@ class InterpreterMacroAssembler: public MacroAssembler {
   // narrow int return value
   void narrow(Register result);
 
-  void profile_taken_branch(Register mdp, Register bumped_count);
+  void profile_taken_branch(Register mdp);
   void profile_not_taken_branch(Register mdp);
   void profile_call(Register mdp);
   void profile_final_call(Register mdp);

src/hotspot/cpu/aarch64/templateTable_aarch64.cpp

@@ -1759,7 +1759,7 @@ void TemplateTable::float_cmp(bool is_float, int unordered_result)
 
 void TemplateTable::branch(bool is_jsr, bool is_wide)
 {
-  __ profile_taken_branch(r0, r1);
+  __ profile_taken_branch(r0);
   const ByteSize be_offset = MethodCounters::backedge_counter_offset() +
                              InvocationCounter::counter_offset();
   const ByteSize inv_offset = MethodCounters::invocation_counter_offset() +
@@ -1809,7 +1809,6 @@ void TemplateTable::branch(bool is_jsr, bool is_wide)
   if (UseLoopCounter) {
     // increment backedge counter for backward branches
     // r0: MDO
-    // w1: MDO bumped taken-count
     // r2: target offset
     __ cmp(r2, zr);
     __ br(Assembler::GT, dispatch); // count only if backward branch