src/cpu/aarch64/vm/aarch64.ad

rev 10232 : 8150038: aarch64: make use of CBZ and CBNZ when comparing narrow pointer with zero
Summary: aarch64: c2 make use of CBZ and CBNZ when comparing narrow pointer with zero
Reviewed-by: duke
Contributed-by: felix.yang@linaro.org

*** 14317,14326 ****
--- 14317,14345 ----
        __ cbnz($op1$$Register, *L);
    %}
    ins_pipe(pipe_cmp_branch);
  %}
  
+ instruct cmpN_imm0_branch(cmpOp cmp, iRegN op1, immN0 op2, label labl, rFlagsReg cr) %{
+   match(If cmp (CmpN op1 op2));
+   predicate(n->in(1)->as_Bool()->_test._test == BoolTest::ne
+             || n->in(1)->as_Bool()->_test._test == BoolTest::eq);
+   effect(USE labl);
+ 
+   ins_cost(BRANCH_COST);
+   format %{ "cbw$cmp   $op1, $labl" %}
+   ins_encode %{
+     Label* L = $labl$$label;
+     Assembler::Condition cond = (Assembler::Condition)$cmp$$cmpcode;
+     if (cond == Assembler::EQ)
+       __ cbzw($op1$$Register, *L);
+     else
+       __ cbnzw($op1$$Register, *L);
+   %}
+   ins_pipe(pipe_cmp_branch);
+ %}
+ 
  instruct cmpP_narrowOop_imm0_branch(cmpOp cmp, iRegN oop, immP0 zero, label labl, rFlagsReg cr) %{
    match(If cmp (CmpP (DecodeN oop) zero));
    predicate(n->in(1)->as_Bool()->_test._test == BoolTest::ne
              || n->in(1)->as_Bool()->_test._test == BoolTest::eq);
    effect(USE labl);