diff --git a/src/arch/arm/insts/branch64.hh b/src/arch/arm/insts/branch64.hh
index 6af5ffcae2..10483a6516 100644
--- a/src/arch/arm/insts/branch64.hh
+++ b/src/arch/arm/insts/branch64.hh
@@ -134,8 +134,7 @@ class BranchRetA64 : public BranchRegReg64
 {
   public:
     BranchRetA64(const char *mnem, ExtMachInst _machInst, OpClass __opClass) :
-        BranchRegReg64(mnem, _machInst, __opClass, INTREG_X30,
-                       makeSP(INTREG_SPX))
+        BranchRegReg64(mnem, _machInst, __opClass, INTREG_X30, INTREG_SPX)
     {}
 
     std::string generateDisassembly(
@@ -162,7 +161,7 @@ class BranchEretA64 : public ArmStaticInst
 
   public:
     BranchEretA64(const char *mnem, ExtMachInst _machInst, OpClass __opClass) :
-        ArmStaticInst(mnem, _machInst, __opClass), op1(makeSP(INTREG_SPX))
+        ArmStaticInst(mnem, _machInst, __opClass), op1(INTREG_SPX)
     {}
 
     std::string generateDisassembly(
diff --git a/src/arch/arm/isa/formats/aarch64.isa b/src/arch/arm/isa/formats/aarch64.isa
index afe0b9de11..a508b30c88 100644
--- a/src/arch/arm/isa/formats/aarch64.isa
+++ b/src/arch/arm/isa/formats/aarch64.isa
@@ -362,28 +362,28 @@ namespace Aarch64
                             switch (op2) {
                               case 0x0:
                                 return new Paciaz(machInst,
-                                         INTREG_X30, makeZero(INTREG_X31));
+                                         INTREG_X30, INTREG_ZERO);
                               case 0x1:
                                 return new Paciasp(machInst,
-                                         INTREG_X30, makeSP(INTREG_SPX));
+                                         INTREG_X30, INTREG_SPX);
                               case 0x2:
                                 return new Pacibz(machInst,
-                                         INTREG_X30, makeZero(INTREG_X31));
+                                         INTREG_X30, INTREG_ZERO);
                               case 0x3:
                                 return new Pacibsp(machInst,
-                                         INTREG_X30, makeSP(INTREG_SPX));
+                                         INTREG_X30, INTREG_SPX);
                               case 0x4:
                                 return new Autiaz(machInst,
-                                         INTREG_X30, makeZero(INTREG_X31));
+                                         INTREG_X30, INTREG_ZERO);
                               case 0x5:
                                 return new Autiasp(machInst,
-                                         INTREG_X30, makeSP(INTREG_SPX));
+                                         INTREG_X30, INTREG_SPX);
                               case 0x6:
                                 return new Autibz(machInst,
-                                         INTREG_X30, makeZero(INTREG_X31));
+                                         INTREG_X30, INTREG_ZERO);
                               case 0x7:
                                 return new Autibsp(machInst,
-                                         INTREG_X30, makeSP(INTREG_SPX));
+                                         INTREG_X30, INTREG_SPX);
                             }
                             break;
                           case 0x4:
@@ -2159,49 +2159,49 @@ namespace Aarch64
                             case 0x8:
                                 if (rn == 0x1f)
                                     return new Paciza(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0x9:
                                 if (rn == 0x1f)
                                     return new Pacizb(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xa:
                                 if (rn == 0x1f)
                                     return new Pacdza(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xb:
                                 if (rn == 0x1f)
                                     return new Pacdzb(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xc:
                                 if (rn == 0x1f)
                                     return new Autiza(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xd:
                                 if (rn == 0x1f)
                                     return new Autizb(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xe:
                                 if (rn == 0x1f)
                                     return new Autdza(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             case 0xf:
                                 if (rn == 0x1f)
                                     return new Autdzb(machInst, rd,
-                                                      makeZero(INTREG_X31));
+                                                      INTREG_ZERO);
                                 else
                                     return new Unknown64(machInst);
                             default: