[V8] Implement SIMD Boolean vector types to allow mask registers.

src/wasm/function-body-decoder-impl.h

Index: src/wasm/function-body-decoder-impl.h
diff --git a/src/wasm/function-body-decoder-impl.h b/src/wasm/function-body-decoder-impl.h
index f723ee0c3f310de7eae1200c115172e4b36e2375..bf0e8cb1e189ec0b37fcba008f457d3a985dd711 100644
--- a/src/wasm/function-body-decoder-impl.h
+++ b/src/wasm/function-body-decoder-impl.h
@@ -144,6 +144,15 @@ struct BlockTypeOperand {
       case kLocalS128:
         *result = kWasmS128;
         return true;
+      case kLocalS4:
+        *result = kWasmS4;

[bradnelson, 2017/02/16 23:18:30]

Maybe S1x4 for consistency?

Would using SB4/8/16 be better? Not sure.

[bbudge, 2017/02/17 23:39:56]

I like S1xN. I'm also going to change the MachineTypes kSimdBoolN to kSimd1xN to
match.

+        return true;
+      case kLocalS8:
+        *result = kWasmS8;
+        return true;
+      case kLocalS16:
+        *result = kWasmS16;
+        return true;
       default:
         *result = kWasmStmt;
         return false;