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

src/wasm/module-decoder.cc

Index: src/wasm/module-decoder.cc
diff --git a/src/wasm/module-decoder.cc b/src/wasm/module-decoder.cc
index e0b3bba1e1aecef26ff973feb4b71f5c7c68536a..23e41cd89258e782202d83d750026a92737c6ed1 100644
--- a/src/wasm/module-decoder.cc
+++ b/src/wasm/module-decoder.cc
@@ -1030,14 +1030,21 @@ class ModuleDecoder : public Decoder {
         return kWasmF32;
       case kLocalF64:
         return kWasmF64;
-      case kLocalS128:
+      default:
         if (origin_ != kAsmJsOrigin && FLAG_wasm_simd_prototype) {
-          return kWasmS128;
-        } else {
-          error(pc_ - 1, "invalid local type");
-          return kWasmStmt;
+          switch (t) {
+            case kLocalS128:
+              return kWasmS128;
+            case kLocalS4:
+              return kWasmS4;
+            case kLocalS8:
+              return kWasmS8;
+            case kLocalS16:
+              return kWasmS16;
+            default:
+              break;
+          }
         }
-      default:
         error(pc_ - 1, "invalid local type");
         return kWasmStmt;
     }