ARM64: Improve IR_UREF code generation.

Thanks to Peter Cawley. #1070

1 files changed, 6 insertions, 8 deletions

diff --git a/src/lj_asm_arm64.h b/src/lj_asm_arm64.h
index c5ebd324..68749284 100644
--- a/src/lj_asm_arm64.h
+++ b/src/lj_asm_arm64.h
@@ -924,18 +924,16 @@ static void asm_uref(ASMState *as, IRIns *ir)
     MRef *v = &gcref(fn->l.uvptr[(ir->op2 >> 8)])->uv.v;
     emit_lsptr(as, A64I_LDRx, dest, v);
   } else {
-    Reg uv = ra_scratch(as, RSET_GPR);
-    Reg func = ra_alloc1(as, ir->op1, RSET_GPR);
     if (ir->o == IR_UREFC) {
-      asm_guardcc(as, CC_NE);
-      emit_n(as, (A64I_CMPx^A64I_K12) | A64F_U12(1), RID_TMP);
-      emit_opk(as, A64I_ADDx, dest, uv,
+      asm_guardcnb(as, A64I_CBZ, RID_TMP);
+      emit_opk(as, A64I_ADDx, dest, dest,
                (int32_t)offsetof(GCupval, tv), RSET_GPR);
-      emit_lso(as, A64I_LDRB, RID_TMP, uv, (int32_t)offsetof(GCupval, closed));
+      emit_lso(as, A64I_LDRB, RID_TMP, dest,
+               (int32_t)offsetof(GCupval, closed));
     } else {
-      emit_lso(as, A64I_LDRx, dest, uv, (int32_t)offsetof(GCupval, v));
+      emit_lso(as, A64I_LDRx, dest, dest, (int32_t)offsetof(GCupval, v));
     }
-    emit_lso(as, A64I_LDRx, uv, func,
+    emit_lso(as, A64I_LDRx, dest, ra_alloc1(as, ir->op1, RSET_GPR),
              (int32_t)offsetof(GCfuncL, uvptr) + 8*(int32_t)(ir->op2 >> 8));
   }
 }