[compiler] [wasm] Introduce Word32/64ReverseBytes as TF Optional Opcode

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index e9045d114499ef3e45b9dba8e439105ecfe4a688..32791ac7764fce02b4fcafce278d1fec773d8958 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -121,13 +121,17 @@ class MachineOperatorBuilder final : public ZoneObject {
     kWord64ReverseBits = 1u << 21,
     kFloat32Neg = 1u << 22,
     kFloat64Neg = 1u << 23,
+    kWord16ReverseBytes = 1u << 24,
+    kWord32ReverseBytes = 1u << 25,
+    kWord64ReverseBytes = 1u << 26,
     kAllOptionalOps =
         kFloat32Max | kFloat32Min | kFloat64Max | kFloat64Min |
         kFloat32RoundDown | kFloat64RoundDown | kFloat32RoundUp |
         kFloat64RoundUp | kFloat32RoundTruncate | kFloat64RoundTruncate |
         kFloat64RoundTiesAway | kFloat32RoundTiesEven | kFloat64RoundTiesEven |
         kWord32Ctz | kWord64Ctz | kWord32Popcnt | kWord64Popcnt |
-        kWord32ReverseBits | kWord64ReverseBits | kFloat32Neg | kFloat64Neg
+        kWord32ReverseBits | kWord64ReverseBits | kFloat32Neg | kFloat64Neg |
+        kWord16ReverseBytes | kWord32ReverseBytes | kWord64ReverseBytes
   };
   typedef base::Flags<Flag, unsigned> Flags;
 
@@ -217,6 +221,9 @@ class MachineOperatorBuilder final : public ZoneObject {
   const OptionalOperator Word64Popcnt();
   const OptionalOperator Word32ReverseBits();
   const OptionalOperator Word64ReverseBits();
+  const OptionalOperator Word16ReverseBytes();
+  const OptionalOperator Word32ReverseBytes();
+  const OptionalOperator Word64ReverseBytes();
   bool Word32ShiftIsSafe() const { return flags_ & kWord32ShiftIsSafe; }
 
   const Operator* Word64And();
@@ -620,6 +627,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   const Operator* AtomicStore(MachineRepresentation rep);
 
   // Target machine word-size assumed by this builder.
+  bool Is16() const { return word() == MachineRepresentation::kWord16; }

[ahaas, 2016/07/27 01:31:15]

The introduction of Is16() worries me. Is a word size of 16 actually supported
in V8? At several places in the code there is the assumption that "Is32() ==
(!Is64())". It seems that the introduction of Is16() violates this assumption.

[john.yan, 2016/07/27 18:18:19]

Ok, I agree. Word16ReverseBytes Opcode is now removed.

   bool Is32() const { return word() == MachineRepresentation::kWord32; }
   bool Is64() const { return word() == MachineRepresentation::kWord64; }
   MachineRepresentation word() const { return word_; }
@@ -636,6 +644,17 @@ class MachineOperatorBuilder final : public ZoneObject {
                                                              alignment);
   }
 
+  bool ReverseBytesSupported(const MachineType& machineType) {

[ahaas, 2016/07/27 01:31:15]

Why is the machineType passed in if it is not used?

[john.yan, 2016/07/27 18:18:19]

Thanks for pointing out. This is my mistake.

+    if (Is16())
+      return Word16ReverseBytes().IsSupported();
+    else if (Is32())
+      return Word32ReverseBytes().IsSupported();
+    else if (Is64())
+      return Word64ReverseBytes().IsSupported();
+    else
+      return false;
+  }
+
 // Pseudo operators that translate to 32/64-bit operators depending on the
 // word-size of the target machine assumed by this builder.
 #define PSEUDO_OP_LIST(V) \