diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 4284456..2a44803 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -996,10 +996,10 @@
     // Unhandled operand.  Halt "fast" selection and bail.
     return false;
 
-  // First issue a copy to GR16_ or GR32_.
+  // First issue a copy to GR16_ABCD or GR32_ABCD.
   unsigned CopyOpc = (SrcVT == MVT::i16) ? X86::MOV16rr : X86::MOV32rr;
   const TargetRegisterClass *CopyRC = (SrcVT == MVT::i16)
-    ? X86::GR16_RegisterClass : X86::GR32_RegisterClass;
+    ? X86::GR16_ABCDRegisterClass : X86::GR32_ABCDRegisterClass;
   unsigned CopyReg = createResultReg(CopyRC);
   BuildMI(MBB, DL, TII.get(CopyOpc), CopyReg).addReg(InputReg);
 
diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index 3084e1c..715eb00 100644
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -1594,18 +1594,18 @@
           (SUBREG_TO_REG
             (i64 0),
             (MOVZX32_NOREXrr8
-              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR64:$src, GR64_),
+              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR64:$src, GR64_ABCD),
                               x86_subreg_8bit_hi)),
             x86_subreg_32bit)>;
 def : Pat<(and (srl_su GR32:$src, (i8 8)), (i32 255)),
           (MOVZX32_NOREXrr8
-            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                             x86_subreg_8bit_hi))>,
       Requires<[In64BitMode]>;
 def : Pat<(srl_su GR16:$src, (i8 8)),
           (EXTRACT_SUBREG
             (MOVZX32_NOREXrr8
-              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                               x86_subreg_8bit_hi)),
             x86_subreg_16bit)>,
       Requires<[In64BitMode]>;
@@ -1614,18 +1614,18 @@
 def : Pat<(store (i8 (trunc_su (srl_su GR64:$src, (i8 8)))), addr:$dst),
           (MOV8mr_NOREX
             addr:$dst,
-            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR64:$src, GR64_),
+            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR64:$src, GR64_ABCD),
                             x86_subreg_8bit_hi))>;
 def : Pat<(store (i8 (trunc_su (srl_su GR32:$src, (i8 8)))), addr:$dst),
           (MOV8mr_NOREX
             addr:$dst,
-            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                             x86_subreg_8bit_hi))>,
       Requires<[In64BitMode]>;
 def : Pat<(store (i8 (trunc_su (srl_su GR16:$src, (i8 8)))), addr:$dst),
           (MOV8mr_NOREX
             addr:$dst,
-            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                             x86_subreg_8bit_hi))>,
       Requires<[In64BitMode]>;
 
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index d8c0833..e748e11 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -1681,13 +1681,13 @@
         Opc = X86::MOV8rr_NOREX;
       else
         Opc = X86::MOV8rr;
-    } else if (CommonRC == &X86::GR64_RegClass) {
+    } else if (CommonRC == &X86::GR64_ABCDRegClass) {
       Opc = X86::MOV64rr;
-    } else if (CommonRC == &X86::GR32_RegClass) {
+    } else if (CommonRC == &X86::GR32_ABCDRegClass) {
       Opc = X86::MOV32rr;
-    } else if (CommonRC == &X86::GR16_RegClass) {
+    } else if (CommonRC == &X86::GR16_ABCDRegClass) {
       Opc = X86::MOV16rr;
-    } else if (CommonRC == &X86::GR8_RegClass) {
+    } else if (CommonRC == &X86::GR8_ABCDRegClass) {
       Opc = X86::MOV8rr;
     } else if (CommonRC == &X86::GR64_NOREXRegClass) {
       Opc = X86::MOV64rr;
@@ -1802,13 +1802,13 @@
     Opc = X86::MOV16mr;
   } else if (RC == &X86::GR8RegClass) {
     Opc = X86::MOV8mr;
-  } else if (RC == &X86::GR64_RegClass) {
+  } else if (RC == &X86::GR64_ABCDRegClass) {
     Opc = X86::MOV64mr;
-  } else if (RC == &X86::GR32_RegClass) {
+  } else if (RC == &X86::GR32_ABCDRegClass) {
     Opc = X86::MOV32mr;
-  } else if (RC == &X86::GR16_RegClass) {
+  } else if (RC == &X86::GR16_ABCDRegClass) {
     Opc = X86::MOV16mr;
-  } else if (RC == &X86::GR8_RegClass) {
+  } else if (RC == &X86::GR8_ABCDRegClass) {
     Opc = X86::MOV8mr;
   } else if (RC == &X86::GR64_NOREXRegClass) {
     Opc = X86::MOV64mr;
@@ -1882,13 +1882,13 @@
     Opc = X86::MOV16rm;
   } else if (RC == &X86::GR8RegClass) {
     Opc = X86::MOV8rm;
-  } else if (RC == &X86::GR64_RegClass) {
+  } else if (RC == &X86::GR64_ABCDRegClass) {
     Opc = X86::MOV64rm;
-  } else if (RC == &X86::GR32_RegClass) {
+  } else if (RC == &X86::GR32_ABCDRegClass) {
     Opc = X86::MOV32rm;
-  } else if (RC == &X86::GR16_RegClass) {
+  } else if (RC == &X86::GR16_ABCDRegClass) {
     Opc = X86::MOV16rm;
-  } else if (RC == &X86::GR8_RegClass) {
+  } else if (RC == &X86::GR8_ABCDRegClass) {
     Opc = X86::MOV8rm;
   } else if (RC == &X86::GR64_NOREXRegClass) {
     Opc = X86::MOV64rm;
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index c8f986a..b01807a 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -3372,12 +3372,12 @@
           (MOVZX32rr16 (EXTRACT_SUBREG GR32:$src1, x86_subreg_16bit))>;
 // r & (2^8-1) ==> movz
 def : Pat<(and GR32:$src1, 0xff),
-          (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src1, GR32_),
+          (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src1, GR32_ABCD),
                                       x86_subreg_8bit))>,
       Requires<[In32BitMode]>;
 // r & (2^8-1) ==> movz
 def : Pat<(and GR16:$src1, 0xff),
-          (MOVZX16rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src1, GR16_),
+          (MOVZX16rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src1, GR16_ABCD),
                                       x86_subreg_8bit))>,
       Requires<[In32BitMode]>;
 
@@ -3385,11 +3385,11 @@
 def : Pat<(sext_inreg GR32:$src, i16),
           (MOVSX32rr16 (EXTRACT_SUBREG GR32:$src, x86_subreg_16bit))>;
 def : Pat<(sext_inreg GR32:$src, i8),
-          (MOVSX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+          (MOVSX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                                       x86_subreg_8bit))>,
       Requires<[In32BitMode]>;
 def : Pat<(sext_inreg GR16:$src, i8),
-          (MOVSX16rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+          (MOVSX16rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                                       x86_subreg_8bit))>,
       Requires<[In32BitMode]>;
 
@@ -3397,32 +3397,32 @@
 def : Pat<(i16 (trunc GR32:$src)),
           (EXTRACT_SUBREG GR32:$src, x86_subreg_16bit)>;
 def : Pat<(i8 (trunc GR32:$src)),
-          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                           x86_subreg_8bit)>,
       Requires<[In32BitMode]>;
 def : Pat<(i8 (trunc GR16:$src)),
-          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                           x86_subreg_8bit)>,
       Requires<[In32BitMode]>;
 
 // h-register tricks
 def : Pat<(i8 (trunc (srl_su GR16:$src, (i8 8)))),
-          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                           x86_subreg_8bit_hi)>,
       Requires<[In32BitMode]>;
 def : Pat<(i8 (trunc (srl_su GR32:$src, (i8 8)))),
-          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+          (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                           x86_subreg_8bit_hi)>,
       Requires<[In32BitMode]>;
 def : Pat<(srl_su GR16:$src, (i8 8)),
           (EXTRACT_SUBREG
             (MOVZX32rr8
-              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_),
+              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                               x86_subreg_8bit_hi)),
             x86_subreg_16bit)>,
       Requires<[In32BitMode]>;
 def : Pat<(and (srl_su GR32:$src, (i8 8)), (i32 255)),
-          (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_),
+          (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                                       x86_subreg_8bit_hi))>,
       Requires<[In32BitMode]>;
 
diff --git a/lib/Target/X86/X86RegisterInfo.td b/lib/Target/X86/X86RegisterInfo.td
index a375868..773cba3 100644
--- a/lib/Target/X86/X86RegisterInfo.td
+++ b/lib/Target/X86/X86RegisterInfo.td
@@ -461,21 +461,21 @@
 }
 
 
-// GR8_, GR16_, GR32_, GR64_ - Subclasses of GR8, GR16, GR32, and GR64
-// which contain just the "a" "b", "c", and "d" registers. On x86-32,
-// GR16_ and GR32_ are classes for registers that support 8-bit subreg
-// operations. On x86-64, GR16_, GR32_, and GR64_ are classes for registers
-// that support 8-bit h-register operations.
-def GR8_ : RegisterClass<"X86", [i8], 8, [AL, CL, DL, BL]> {
+// GR8_ABCD, GR16_ABCD, GR32_ABCD, GR64_ABCD - Subclasses of GR8, GR16, GR32,
+// and GR64 which contain just the "a" "b", "c", and "d" registers. On x86-32,
+// GR16_ABCD and GR32_ABCD are classes for registers that support 8-bit subreg
+// operations. On x86-64, GR16_ABCD, GR32_ABCD, and GR64_ABCD are classes for
+// registers that support 8-bit h-register operations.
+def GR8_ABCD : RegisterClass<"X86", [i8], 8, [AL, CL, DL, BL]> {
 }
-def GR16_ : RegisterClass<"X86", [i16], 16, [AX, CX, DX, BX]> {
-  let SubRegClassList = [GR8_, GR8_];
+def GR16_ABCD : RegisterClass<"X86", [i16], 16, [AX, CX, DX, BX]> {
+  let SubRegClassList = [GR8_ABCD, GR8_ABCD];
 }
-def GR32_ : RegisterClass<"X86", [i32], 32, [EAX, ECX, EDX, EBX]> {
-  let SubRegClassList = [GR8_, GR8_, GR16_];
+def GR32_ABCD : RegisterClass<"X86", [i32], 32, [EAX, ECX, EDX, EBX]> {
+  let SubRegClassList = [GR8_ABCD, GR8_ABCD, GR16_ABCD];
 }
-def GR64_ : RegisterClass<"X86", [i64], 64, [RAX, RCX, RDX, RBX]> {
-  let SubRegClassList = [GR8_, GR8_, GR16_, GR32_];
+def GR64_ABCD : RegisterClass<"X86", [i64], 64, [RAX, RCX, RDX, RBX]> {
+  let SubRegClassList = [GR8_ABCD, GR8_ABCD, GR16_ABCD, GR32_ABCD];
 }
 
 // GR8_NOREX, GR16_NOREX, GR32_NOREX, GR64_NOREX - Subclasses of