src/hotspot/cpu/x86/templateTable_x86.cpp

*** 2440,2451 ****
  }
  
  void TemplateTable::if_acmp(Condition cc) {
    transition(atos, vtos);
    // assume branch is more often taken than not (loops use backward branches)
!   Label not_taken;
    __ pop_ptr(rdx);
    __ cmpoop(rdx, rax);
    __ jcc(j_not(cc), not_taken);
    branch(false, false);
    __ bind(not_taken);
    __ profile_not_taken_branch(rax);
--- 2440,2470 ----
  }
  
  void TemplateTable::if_acmp(Condition cc) {
    transition(atos, vtos);
    // assume branch is more often taken than not (loops use backward branches)
!   Label not_taken, is_null;
    __ pop_ptr(rdx);
+ 
+   if (UseNewAcmp) {
+     // TODO what about interpreter buffered values?
+     const int mask = Universe::oop_metadata_odd_mask();
+     __ testptr(rdx, rdx);
+     __ jcc(Assembler::zero, is_null);
+     __ movl(rbx, Address(rdx, oopDesc::klass_offset_in_bytes()));
+     __ andptr(rbx, mask);
+     // Check if a shift is required for perturbation to affect aligned bits
+     if (mask == KlassPtrEvenOddMask && ObjectAlignmentInBytes <= KlassAlignmentInBytes) {
+       assert((mask >> LogKlassAlignmentInBytes) == 1, "invalid shift");
+       __ shrptr(rbx, LogKlassAlignmentInBytes);
+     } else {
+       assert(mask < ObjectAlignmentInBytes, "invalid mask");
+     }
+     __ orptr(rdx, rbx);
+     __ bind(is_null);
+   }
+ 
    __ cmpoop(rdx, rax);
    __ jcc(j_not(cc), not_taken);
    branch(false, false);
    __ bind(not_taken);
    __ profile_not_taken_branch(rax);