[llvm] [X86][MC] Support encoding/decoding for APX variant INC/DEC/ADCX/ADOX instructions (PR #76721)

[Phoebe Wang via llvm-commits]

================
@@ -184,52 +184,139 @@ def IMUL64rmi32 : IMulOpMI_R<Xi64, WriteIMul64Imm>;
 //===----------------------------------------------------------------------===//
 // INC and DEC Instructions
 //
-class IncOpR_RF<X86TypeInfo t> : UnaryOpR_RF<0xFF, MRM0r, "inc", t, null_frag> {
+class IncOpR_RF<X86TypeInfo t, bit ndd = 0> : UnaryOpR_RF<0xFF, MRM0r, "inc", t, null_frag, ndd> {
   let Pattern = [(set t.RegClass:$dst, EFLAGS,
                  (X86add_flag_nocf t.RegClass:$src1, 1))];
 }
-class DecOpR_RF<X86TypeInfo t> : UnaryOpR_RF<0xFF, MRM1r, "dec", t, null_frag> {
+class DecOpR_RF<X86TypeInfo t, bit ndd = 0> : UnaryOpR_RF<0xFF, MRM1r, "dec", t, null_frag, ndd> {
   let Pattern = [(set t.RegClass:$dst, EFLAGS,
                  (X86sub_flag_nocf t.RegClass:$src1, 1))];
 }
-class IncOpM_M<X86TypeInfo t> : UnaryOpM_MF<0xFF, MRM0m, "inc", t, null_frag> {
+class IncOpR_R<X86TypeInfo t, bit ndd = 0> : UnaryOpR_R<0xFF, MRM0r, "inc", t, null_frag, ndd>;
+class DecOpR_R<X86TypeInfo t, bit ndd = 0> : UnaryOpR_R<0xFF, MRM1r, "dec", t, null_frag, ndd>;
+class IncOpM_MF<X86TypeInfo t> : UnaryOpM_MF<0xFF, MRM0m, "inc", t, null_frag> {
   let Pattern = [(store (add (t.LoadNode addr:$src1), 1), addr:$src1),
                  (implicit EFLAGS)];
 }
-class DecOpM_M<X86TypeInfo t> : UnaryOpM_MF<0xFF, MRM1m, "dec", t, null_frag> {
+class DecOpM_MF<X86TypeInfo t> : UnaryOpM_MF<0xFF, MRM1m, "dec", t, null_frag> {
   let Pattern = [(store (add (t.LoadNode addr:$src1), -1), addr:$src1),
                  (implicit EFLAGS)];
 }
+class IncOpM_RF<X86TypeInfo t> : UnaryOpM_RF<0xFF, MRM0m, "inc", t, null_frag> {
+  let Pattern = [(set t.RegClass:$dst, EFLAGS, (add (t.LoadNode addr:$src1), 1))];
+}
+class DecOpM_RF<X86TypeInfo t> : UnaryOpM_RF<0xFF, MRM1m, "dec", t, null_frag> {
+  let Pattern = [(set t.RegClass:$dst, EFLAGS, (add (t.LoadNode addr:$src1), -1))];
+}
+class IncOpM_M<X86TypeInfo t> : UnaryOpM_M<0xFF, MRM0m, "inc", t, null_frag>;
+class DecOpM_M<X86TypeInfo t> : UnaryOpM_M<0xFF, MRM1m, "dec", t, null_frag>;
+class IncOpM_R<X86TypeInfo t> : UnaryOpM_R<0xFF, MRM0m, "inc", t, null_frag>;
+class DecOpM_R<X86TypeInfo t> : UnaryOpM_R<0xFF, MRM1m, "dec", t, null_frag>;
+
 // IncDec_Alt - Instructions like "inc reg" short forms.
 // Short forms only valid in 32-bit mode. Selected during MCInst lowering.
 class IncDec_Alt<bits<8> o, string m, X86TypeInfo t>
   : UnaryOpR_RF<o, AddRegFrm, m, t, null_frag>, Requires<[Not64BitMode]>;
 
 let isConvertibleToThreeAddress = 1 in {
-def INC16r_alt : IncDec_Alt<0x40, "inc", Xi16>, OpSize16;
-def INC32r_alt : IncDec_Alt<0x40, "inc", Xi32>, OpSize32;
-def DEC16r_alt : IncDec_Alt<0x48, "dec", Xi16>, OpSize16;
-def DEC32r_alt : IncDec_Alt<0x48, "dec", Xi32>, OpSize32;
-def INC8r  : IncOpR_RF<Xi8>;
-def INC16r : IncOpR_RF<Xi16>, OpSize16;
-def INC32r : IncOpR_RF<Xi32>, OpSize32;
-def INC64r : IncOpR_RF<Xi64>;
-def DEC8r  : DecOpR_RF<Xi8>;
-def DEC16r : DecOpR_RF<Xi16>, OpSize16;
-def DEC32r : DecOpR_RF<Xi32>, OpSize32;
-def DEC64r : DecOpR_RF<Xi64>;
+  def INC16r_alt : IncDec_Alt<0x40, "inc", Xi16>, OpSize16;
+  def INC32r_alt : IncDec_Alt<0x40, "inc", Xi32>, OpSize32;
+  def DEC16r_alt : IncDec_Alt<0x48, "dec", Xi16>, OpSize16;
+  def DEC32r_alt : IncDec_Alt<0x48, "dec", Xi32>, OpSize32;
+  let Predicates = [NoNDD] in {
+    def INC8r  : IncOpR_RF<Xi8>;
+    def INC16r : IncOpR_RF<Xi16>, OpSize16;
+    def INC32r : IncOpR_RF<Xi32>, OpSize32;
+    def INC64r : IncOpR_RF<Xi64>;
+    def DEC8r  : DecOpR_RF<Xi8>;
+    def DEC16r : DecOpR_RF<Xi16>, OpSize16;
+    def DEC32r : DecOpR_RF<Xi32>, OpSize32;
+    def DEC64r : DecOpR_RF<Xi64>;
+  }
+  let Predicates = [HasNDD, In64BitMode] in {
+    def INC8r_ND  : IncOpR_RF<Xi8, 1>;
+    def INC16r_ND : IncOpR_RF<Xi16, 1>, PD;
+    def INC32r_ND : IncOpR_RF<Xi32, 1>;
+    def INC64r_ND : IncOpR_RF<Xi64, 1>;
+    def DEC8r_ND  : DecOpR_RF<Xi8, 1>;
+    def DEC16r_ND : DecOpR_RF<Xi16, 1>, PD;
+    def DEC32r_ND : DecOpR_RF<Xi32, 1>;
+    def DEC64r_ND : DecOpR_RF<Xi64, 1>;
+  }
+  let Predicates = [In64BitMode], Pattern = [(null_frag)] in {
----------------
phoebewang wrote:

Why set `Pattern = [(null_frag)]` here given both `IncOpR_R` and `IncOpR_RF` already pass `null_frag` by default?

https://github.com/llvm/llvm-project/pull/76721