[Tablegen] Bugfix and refactor VarLenCodeEmitter HwModes.

llvm/test/TableGen/VarLenEncoderHwModes.td

@@ -0,0 +1,98 @@
+// RUN: llvm-tblgen -gen-emitter -I %p/../../include %s | FileCheck %s
+
+// Verify VarLenCodeEmitterGen using EncodingInfos with different HwModes.
+
+include "llvm/Target/Target.td"
+
+def ArchInstrInfo : InstrInfo { }
+
+def Arch : Target {
+  let InstructionSet = ArchInstrInfo;
+}
+
+def Reg : Register<"reg">;
+
+def RegClass : RegisterClass<"foo", [i64], 0, (add Reg)>;
+
+def GR64 : RegisterOperand<RegClass>;
+
+def HasA : Predicate<"Subtarget->hasA()">;
+def HasB : Predicate<"Subtarget->hasB()">;
+
+def ModeA : HwMode<"+a", [HasA]>;
+def ModeB : HwMode<"+b", [HasB]>;
+
+def fooTypeEncA : InstructionEncoding {
+  dag Inst = (descend
+    (operand "$src", 4),
+    (operand "$dst", 4),
+    0b00000001
+  );
+}
+
+def fooTypeEncB : InstructionEncoding {
+  dag Inst = (descend
+    (operand "$dst", 4),
+    (operand "$src", 4),
+    0b00000010
+  );
+}
+
+def fooTypeEncC : InstructionEncoding {
+  dag Inst = (descend
+    (operand "$dst", 4),
+    (operand "$src", 4),
+    0b00000100
+  );
+}
+
+class VarLenInst : Instruction {
+  let AsmString = "foo $src, $dst";
+  let OutOperandList = (outs GR64:$dst);
+  let InOperandList  = (ins GR64:$src);
+}
+
+// Defined in both HwModes
+def foo : VarLenInst {
+  let EncodingInfos = EncodingByHwMode<
+    [ModeA, ModeB],
+    [fooTypeEncA, fooTypeEncB]
+  >;
+}
+
+// Same encoding in any HwMode
+def bar : VarLenInst {
+  dag Inst = (descend
+    (operand "$dst", 4),
+    (operand "$src", 4),
+    0b00000011
+  );
+}
+
+// Only defined in HwMode B.
+def baz : VarLenInst {
+  let EncodingInfos = EncodingByHwMode<
+    [ModeB],
+    [fooTypeEncC]
+  >;
+}
+
+// CHECK:   static const uint64_t InstBits_ModeA[] = {
+// CHECK:         UINT64_C(3),        // bar
+// CHECK:         UINT64_C(1),        // foo
+
+// CHECK:   static const uint64_t InstBits_ModeB[] = {
+// CHECK:         UINT64_C(3),        // bar
+// CHECK:         UINT64_C(4),        // baz
+// CHECK:         UINT64_C(2),        // foo
+
+// CHECK:     case ::bar: {
+// CHECK-NOT:      switch (Mode) {
+
+// CHECK:     case ::foo: {
+// CHECK:      switch (Mode) {
+
+// CHECK:     case ::baz: {
+// CHECK:      case 1: {
+// CHECK:      llvm_unreachable("Undefined encoding in this mode");
+// CHECK:      case 2: {