src/cpu/aarch64/vm/c1_LIRAssembler_aarch64.cpp

rev 13098 : 8182161: aarch64: combine andr+cbnz into tbnz when possible
Summary: Combine andr+cbnz into tbnz when possible to save one instruction
Reviewed-by: aph

*** 2738,2749 ****
          __ andr(rscratch1, tmp, TypeEntries::type_klass_mask);
          // klass seen before, nothing to do. The unknown bit may have been
          // set already but no need to check.
          __ cbz(rscratch1, next);
  
!         __ andr(rscratch1, tmp, TypeEntries::type_unknown);
!         __ cbnz(rscratch1, next); // already unknown. Nothing to do anymore.
  
          if (TypeEntries::is_type_none(current_klass)) {
            __ cbz(rscratch2, none);
            __ cmp(rscratch2, TypeEntries::null_seen);
            __ br(Assembler::EQ, none);
--- 2738,2748 ----
          __ andr(rscratch1, tmp, TypeEntries::type_klass_mask);
          // klass seen before, nothing to do. The unknown bit may have been
          // set already but no need to check.
          __ cbz(rscratch1, next);
  
!         __ tbnz(tmp, exact_log2(TypeEntries::type_unknown), next); // already unknown. Nothing to do anymore.
  
          if (TypeEntries::is_type_none(current_klass)) {
            __ cbz(rscratch2, none);
            __ cmp(rscratch2, TypeEntries::null_seen);
            __ br(Assembler::EQ, none);
*** 2759,2770 ****
        } else {
          assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
                 ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "conflict only");
  
          __ ldr(tmp, mdo_addr);
!         __ andr(rscratch1, tmp, TypeEntries::type_unknown);
!         __ cbnz(rscratch1, next); // already unknown. Nothing to do anymore.
        }
  
        // different than before. Cannot keep accurate profile.
        __ ldr(rscratch2, mdo_addr);
        __ orr(rscratch2, rscratch2, TypeEntries::type_unknown);
--- 2758,2768 ----
        } else {
          assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
                 ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "conflict only");
  
          __ ldr(tmp, mdo_addr);
!         __ tbnz(tmp, exact_log2(TypeEntries::type_unknown), next); // already unknown. Nothing to do anymore.
        }
  
        // different than before. Cannot keep accurate profile.
        __ ldr(rscratch2, mdo_addr);
        __ orr(rscratch2, rscratch2, TypeEntries::type_unknown);
*** 2810,2821 ****
        } else {
          assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
                 ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "inconsistent");
  
          __ ldr(tmp, mdo_addr);
!         __ andr(rscratch1, tmp, TypeEntries::type_unknown);
!         __ cbnz(rscratch1, next); // already unknown. Nothing to do anymore.
  
          __ orr(tmp, tmp, TypeEntries::type_unknown);
          __ str(tmp, mdo_addr);
          // FIXME: Write barrier needed here?
        }
--- 2808,2818 ----
        } else {
          assert(ciTypeEntries::valid_ciklass(current_klass) != NULL &&
                 ciTypeEntries::valid_ciklass(current_klass) != exact_klass, "inconsistent");
  
          __ ldr(tmp, mdo_addr);
!         __ tbnz(tmp, exact_log2(TypeEntries::type_unknown), next); // already unknown. Nothing to do anymore.
  
          __ orr(tmp, tmp, TypeEntries::type_unknown);
          __ str(tmp, mdo_addr);
          // FIXME: Write barrier needed here?
        }