diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index e5949c0ebec..378e0d80dba 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -992,125 +992,6 @@ Node* WasmGraphBuilder::MaskShiftCount64(Node* node) {
   return node;
 }
 
-Node* WasmGraphBuilder::BuildChangeEndianness(Node* node, MachineType memtype,
-                                              wasm::LocalType wasmtype) {
-  Node* result;
-  Node* value = node;
-  const Operator* shiftLeftOpcode;
-  const Operator* shiftRightOpcode;
-  const Operator* andOpcode;
-  const Operator* orOpcode;
-  MachineOperatorBuilder* m = jsgraph()->machine();
-  int valueSizeInBytes = 1 << ElementSizeLog2Of(memtype.representation());
-  int valueSizeInBits = 8 * valueSizeInBytes;
-  bool isFloat = false;
-
-  switch (memtype.representation()) {
-    case MachineRepresentation::kFloat64:
-      value = graph()->NewNode(m->BitcastFloat64ToInt64(), node);
-      isFloat = true;
-    case MachineRepresentation::kWord64:
-      shiftLeftOpcode = m->Word64Shl();
-      shiftRightOpcode = m->Word64Shr();
-      andOpcode = m->Word64And();
-      orOpcode = m->Word64Or();
-      result = jsgraph()->Int64Constant(0);
-      break;
-    case MachineRepresentation::kFloat32:
-      value = graph()->NewNode(m->BitcastFloat32ToInt32(), node);
-      isFloat = true;
-    case MachineRepresentation::kWord32:
-    case MachineRepresentation::kWord16:
-      shiftLeftOpcode = m->Word32Shl();
-      shiftRightOpcode = m->Word32Shr();
-      andOpcode = m->Word32And();
-      orOpcode = m->Word32Or();
-      result = jsgraph()->Int32Constant(0);
-      break;
-    case MachineRepresentation::kWord8:
-      // No need to change endianness for byte size, return original node
-      return node;
-      break;
-    default:
-      UNREACHABLE();
-      break;
-  }
-
-  int i;
-  uint32_t shiftCount;
-
-  for (i = 0, shiftCount = valueSizeInBits - 8; i < valueSizeInBits / 2;
-       i += 8, shiftCount -= 16) {
-    DCHECK(shiftCount > 0);
-    DCHECK((shiftCount + 8) % 16 == 0);
-
-    Node* shiftLower = graph()->NewNode(shiftLeftOpcode, value,
-                                        jsgraph()->Int32Constant(shiftCount));
-    Node* shiftHigher = graph()->NewNode(shiftRightOpcode, value,
-                                         jsgraph()->Int32Constant(shiftCount));
-
-    Node* lowerByte;
-    Node* higherByte;
-
-    if (valueSizeInBits > 32) {
-      lowerByte = graph()->NewNode(
-          andOpcode, shiftLower,
-          jsgraph()->Int64Constant(0xFFl << (valueSizeInBits - 8 - i)));
-      higherByte = graph()->NewNode(andOpcode, shiftHigher,
-                                    jsgraph()->Int64Constant(0xFFl << i));
-    } else {
-      lowerByte = graph()->NewNode(
-          andOpcode, shiftLower,
-          jsgraph()->Int32Constant(0xFF << (valueSizeInBits - 8 - i)));
-      higherByte = graph()->NewNode(andOpcode, shiftHigher,
-                                    jsgraph()->Int32Constant(0xFF << i));
-    }
-
-    result = graph()->NewNode(orOpcode, result, lowerByte);
-    result = graph()->NewNode(orOpcode, result, higherByte);
-  }
-
-  if (isFloat) {
-    switch (memtype.representation()) {
-      case MachineRepresentation::kFloat64:
-        result = graph()->NewNode(m->BitcastInt64ToFloat64(), result);
-        break;
-      case MachineRepresentation::kFloat32:
-        result = graph()->NewNode(m->BitcastInt32ToFloat32(), result);
-        break;
-      default:
-        UNREACHABLE();
-        break;
-    }
-  }
-
-  // We need to sign extend the value
-  if (memtype.IsSigned()) {
-    DCHECK(!isFloat);
-    if (valueSizeInBits < 32) {
-      Node* shiftBitCount;
-      // Perform sign extension using following trick
-      // result = (x << machine_width - type_width) >> (machine_width -
-      // type_width)
-      if (wasmtype == wasm::kAstI64) {
-        shiftBitCount = jsgraph()->Int32Constant(64 - valueSizeInBits);
-        result = graph()->NewNode(
-            m->Word64Sar(),
-            graph()->NewNode(m->Word64Shl(), result, shiftBitCount),
-            shiftBitCount);
-      } else if (wasmtype == wasm::kAstI32) {
-        shiftBitCount = jsgraph()->Int32Constant(32 - valueSizeInBits);
-        result = graph()->NewNode(
-            m->Word32Sar(),
-            graph()->NewNode(m->Word32Shl(), result, shiftBitCount),
-            shiftBitCount);
-      }
-    }
-  }
-
-  return result;
-}
-
 Node* WasmGraphBuilder::BuildF32Neg(Node* input) {
   Node* result =
       Unop(wasm::kExprF32ReinterpretI32,
@@ -2868,11 +2749,6 @@ Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
   } else {
     load = BuildUnalignedLoad(type, memtype, index, offset, alignment);
   }
-#if defined(V8_TARGET_BIG_ENDIAN)
-  // TODO(john.yan) Implement byte swap turbofan operator
-  // and use it if available for better performance
-  load = BuildChangeEndianness(load, memtype, type);
-#endif
 
   if (type == wasm::kAstI64 &&
       ElementSizeLog2Of(memtype.representation()) < 3) {
@@ -2993,12 +2869,6 @@ Node* WasmGraphBuilder::StoreMem(MachineType memtype, Node* index,
   bool aligned = static_cast<int>(alignment) >=
                  ElementSizeLog2Of(memtype.representation());
 
-#if defined(V8_TARGET_BIG_ENDIAN)
-  // TODO(john.yan) Implement byte swap turbofan operator
-  // and use it if available for better performance
-  val = BuildChangeEndianness(val, memtype);
-#endif
-
   if (aligned ||
       jsgraph()->machine()->UnalignedStoreSupported(memtype, alignment)) {
     StoreRepresentation rep(memtype.representation(), kNoWriteBarrier);
diff --git a/src/compiler/wasm-compiler.h b/src/compiler/wasm-compiler.h
index 528cd87d42c..bd8080b0613 100644
--- a/src/compiler/wasm-compiler.h
+++ b/src/compiler/wasm-compiler.h
@@ -234,9 +234,6 @@ class WasmGraphBuilder {
   Node* BuildUnalignedStore(MachineType memtype, Node* index, uint32_t offset,
                             uint32_t alignment, Node* val);
 
-  Node* BuildChangeEndianness(Node* node, MachineType type,
-                              wasm::LocalType wasmtype = wasm::kAstStmt);
-
   Node* MaskShiftCount32(Node* node);
   Node* MaskShiftCount64(Node* node);
 
diff --git a/src/utils.h b/src/utils.h
index 2acc95ef3c0..9b94a2feb1d 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -1552,33 +1552,6 @@ static inline void WriteUnalignedUInt32(void* p, uint32_t value) {
   WriteUnalignedValue(p, value);
 }
 
-template <typename V>
-static inline V ReadLittleEndianValue(const void* p) {
-#if defined(V8_TARGET_LITTLE_ENDIAN)
-  return ReadUnalignedValue<V>(p);
-#elif defined(V8_TARGET_BIG_ENDIAN)
-  V ret = 0;
-  const byte* src = reinterpret_cast<const byte*>(p);
-  byte* dst = reinterpret_cast<byte*>(&ret);
-  for (size_t i = 0; i < sizeof(V); i++) {
-    dst[i] = src[sizeof(V) - i - 1];
-  }
-  return ret;
-#endif  // V8_TARGET_LITTLE_ENDIAN
-}
-
-template <typename V>
-static inline void WriteLittleEndianValue(void* p, V value) {
-#if defined(V8_TARGET_LITTLE_ENDIAN)
-  WriteUnalignedValue<V>(p, value);
-#elif defined(V8_TARGET_BIG_ENDIAN)
-  byte* src = reinterpret_cast<byte*>(&value);
-  byte* dst = reinterpret_cast<byte*>(p);
-  for (size_t i = 0; i < sizeof(V); i++) {
-    dst[i] = src[sizeof(V) - i - 1];
-  }
-#endif  // V8_TARGET_LITTLE_ENDIAN
-}
 }  // namespace internal
 }  // namespace v8
 
diff --git a/src/wasm/decoder.h b/src/wasm/decoder.h
index cc8024c82fe..9136fa511d4 100644
--- a/src/wasm/decoder.h
+++ b/src/wasm/decoder.h
@@ -26,6 +26,12 @@ namespace wasm {
 #define TRACE(...)
 #endif
 
+#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
+#define UNALIGNED_ACCESS_OK 1
+#else
+#define UNALIGNED_ACCESS_OK 0
+#endif
+
 // A helper utility to decode bytes, integers, fields, varints, etc, from
 // a buffer of bytes.
 class Decoder {
@@ -116,19 +122,47 @@ class Decoder {
   // Reads a single 16-bit unsigned integer (little endian).
   inline uint16_t read_u16(const byte* ptr) {
     DCHECK(ptr >= start_ && (ptr + 2) <= end_);
-    return ReadLittleEndianValue<uint16_t>(ptr);
+#if V8_TARGET_LITTLE_ENDIAN && UNALIGNED_ACCESS_OK
+    return *reinterpret_cast<const uint16_t*>(ptr);
+#else
+    uint16_t b0 = ptr[0];
+    uint16_t b1 = ptr[1];
+    return (b1 << 8) | b0;
+#endif
   }
 
   // Reads a single 32-bit unsigned integer (little endian).
   inline uint32_t read_u32(const byte* ptr) {
     DCHECK(ptr >= start_ && (ptr + 4) <= end_);
-    return ReadLittleEndianValue<uint32_t>(ptr);
+#if V8_TARGET_LITTLE_ENDIAN && UNALIGNED_ACCESS_OK
+    return *reinterpret_cast<const uint32_t*>(ptr);
+#else
+    uint32_t b0 = ptr[0];
+    uint32_t b1 = ptr[1];
+    uint32_t b2 = ptr[2];
+    uint32_t b3 = ptr[3];
+    return (b3 << 24) | (b2 << 16) | (b1 << 8) | b0;
+#endif
   }
 
   // Reads a single 64-bit unsigned integer (little endian).
   inline uint64_t read_u64(const byte* ptr) {
     DCHECK(ptr >= start_ && (ptr + 8) <= end_);
-    return ReadLittleEndianValue<uint64_t>(ptr);
+#if V8_TARGET_LITTLE_ENDIAN && UNALIGNED_ACCESS_OK
+    return *reinterpret_cast<const uint64_t*>(ptr);
+#else
+    uint32_t b0 = ptr[0];
+    uint32_t b1 = ptr[1];
+    uint32_t b2 = ptr[2];
+    uint32_t b3 = ptr[3];
+    uint32_t low = (b3 << 24) | (b2 << 16) | (b1 << 8) | b0;
+    uint32_t b4 = ptr[4];
+    uint32_t b5 = ptr[5];
+    uint32_t b6 = ptr[6];
+    uint32_t b7 = ptr[7];
+    uint64_t high = (b7 << 24) | (b6 << 16) | (b5 << 8) | b4;
+    return (high << 32) | low;
+#endif
   }
 
   // Reads a 8-bit unsigned integer (byte) and advances {pc_}.
diff --git a/src/wasm/encoder.h b/src/wasm/encoder.h
index ea4dbe0d424..19fc39703d6 100644
--- a/src/wasm/encoder.h
+++ b/src/wasm/encoder.h
@@ -36,13 +36,25 @@ class ZoneBuffer : public ZoneObject {
 
   void write_u16(uint16_t x) {
     EnsureSpace(2);
-    WriteLittleEndianValue<uint16_t>(pos_, x);
+#if V8_TARGET_LITTLE_ENDIAN
+    WriteUnalignedUInt16(pos_, x);
+#else
+    pos_[0] = x & 0xff;
+    pos_[1] = (x >> 8) & 0xff;
+#endif
     pos_ += 2;
   }
 
   void write_u32(uint32_t x) {
     EnsureSpace(4);
-    WriteLittleEndianValue<uint32_t>(pos_, x);
+#if V8_TARGET_LITTLE_ENDIAN
+    WriteUnalignedUInt32(pos_, x);
+#else
+    pos_[0] = x & 0xff;
+    pos_[1] = (x >> 8) & 0xff;
+    pos_[2] = (x >> 16) & 0xff;
+    pos_[3] = (x >> 24) & 0xff;
+#endif
     pos_ += 4;
   }
 
diff --git a/src/wasm/wasm-interpreter.cc b/src/wasm/wasm-interpreter.cc
index c5cedefa343..fc727801b98 100644
--- a/src/wasm/wasm-interpreter.cc
+++ b/src/wasm/wasm-interpreter.cc
@@ -1437,20 +1437,20 @@ class ThreadImpl : public WasmInterpreter::Thread {
           break;
         }
 
-#define LOAD_CASE(name, ctype, mtype)                                       \
-  case kExpr##name: {                                                       \
-    MemoryAccessOperand operand(&decoder, code->at(pc));                    \
-    uint32_t index = Pop().to<uint32_t>();                                  \
-    size_t effective_mem_size = instance()->mem_size - sizeof(mtype);       \
-    if (operand.offset > effective_mem_size ||                              \
-        index > (effective_mem_size - operand.offset)) {                    \
-      return DoTrap(kTrapMemOutOfBounds, pc);                               \
-    }                                                                       \
-    byte* addr = instance()->mem_start + operand.offset + index;            \
-    WasmVal result(static_cast<ctype>(ReadLittleEndianValue<mtype>(addr))); \
-    Push(pc, result);                                                       \
-    len = 1 + operand.length;                                               \
-    break;                                                                  \
+#define LOAD_CASE(name, ctype, mtype)                                    \
+  case kExpr##name: {                                                    \
+    MemoryAccessOperand operand(&decoder, code->at(pc));                 \
+    uint32_t index = Pop().to<uint32_t>();                               \
+    size_t effective_mem_size = instance()->mem_size - sizeof(mtype);    \
+    if (operand.offset > effective_mem_size ||                           \
+        index > (effective_mem_size - operand.offset)) {                 \
+      return DoTrap(kTrapMemOutOfBounds, pc);                            \
+    }                                                                    \
+    byte* addr = instance()->mem_start + operand.offset + index;         \
+    WasmVal result(static_cast<ctype>(ReadUnalignedValue<mtype>(addr))); \
+    Push(pc, result);                                                    \
+    len = 1 + operand.length;                                            \
+    break;                                                               \
   }
 
           LOAD_CASE(I32LoadMem8S, int32_t, int8_t);
@@ -1469,21 +1469,21 @@ class ThreadImpl : public WasmInterpreter::Thread {
           LOAD_CASE(F64LoadMem, double, double);
 #undef LOAD_CASE
 
-#define STORE_CASE(name, ctype, mtype)                                        \
-  case kExpr##name: {                                                         \
-    MemoryAccessOperand operand(&decoder, code->at(pc));                      \
-    WasmVal val = Pop();                                                      \
-    uint32_t index = Pop().to<uint32_t>();                                    \
-    size_t effective_mem_size = instance()->mem_size - sizeof(mtype);         \
-    if (operand.offset > effective_mem_size ||                                \
-        index > (effective_mem_size - operand.offset)) {                      \
-      return DoTrap(kTrapMemOutOfBounds, pc);                                 \
-    }                                                                         \
-    byte* addr = instance()->mem_start + operand.offset + index;              \
-    WriteLittleEndianValue<mtype>(addr, static_cast<mtype>(val.to<ctype>())); \
-    Push(pc, val);                                                            \
-    len = 1 + operand.length;                                                 \
-    break;                                                                    \
+#define STORE_CASE(name, ctype, mtype)                                     \
+  case kExpr##name: {                                                      \
+    MemoryAccessOperand operand(&decoder, code->at(pc));                   \
+    WasmVal val = Pop();                                                   \
+    uint32_t index = Pop().to<uint32_t>();                                 \
+    size_t effective_mem_size = instance()->mem_size - sizeof(mtype);      \
+    if (operand.offset > effective_mem_size ||                             \
+        index > (effective_mem_size - operand.offset)) {                   \
+      return DoTrap(kTrapMemOutOfBounds, pc);                              \
+    }                                                                      \
+    byte* addr = instance()->mem_start + operand.offset + index;           \
+    WriteUnalignedValue<mtype>(addr, static_cast<mtype>(val.to<ctype>())); \
+    Push(pc, val);                                                         \
+    len = 1 + operand.length;                                              \
+    break;                                                                 \
   }
 
           STORE_CASE(I32StoreMem8, int32_t, int8_t);
diff --git a/test/cctest/cctest.status b/test/cctest/cctest.status
index b1569365a2e..a73271eadff 100644
--- a/test/cctest/cctest.status
+++ b/test/cctest/cctest.status
@@ -294,6 +294,25 @@
   'test-cpu-profiler/JsNative1JsNative2JsSample': [SKIP],
 }],  # 'system == windows'
 
+##############################################################################
+['byteorder == big', {
+  # TODO(mips-team): Fix Wasm for big-endian.
+  'test-run-wasm-module/Run_WasmModule_CallAdd': [SKIP],
+  'test-run-wasm-module/Run_WasmModule_CallMain_recursive': [SKIP],
+  'test-run-wasm-module/Run_WasmModule_ReadLoadedDataSegment': [SKIP],
+  'test-run-wasm-module/Run_WasmModule_Return114': [SKIP],
+  'test-run-wasm-module/Run_WasmModule_CheckMemoryIsZero': [SKIP],
+  'test-run-wasm-module/Run_WasmModule_Global': [SKIP],
+  'test-run-wasm/RunWasmCompiled_Int32LoadInt16_signext': [SKIP],
+  'test-run-wasm/RunWasmCompiled_Int32LoadInt16_zeroext': [SKIP],
+  'test-run-wasm/RunWasmCompiled_MixedGlobals': [SKIP],
+  'test-run-wasm-64/RunWasmCompiled_I64*': [SKIP],
+  'test-run-wasm-64/RunWasmCompiled_LoadStoreI64_sx': [SKIP],
+  'test-run-wasm-64/Run_TestI64WasmRunner': [SKIP],
+  'test-run-wasm-64/RunWasmCompiled_Call_Int64Sub': [SKIP],
+  'test-run-wasm-64/RunWasmCompiled_MemI64_Sum': [SKIP],
+}],  # 'byteorder == big'
+
 ##############################################################################
 ['arch == arm', {
 
diff --git a/test/cctest/wasm/test-run-wasm-64.cc b/test/cctest/wasm/test-run-wasm-64.cc
index 404960abf04..af8749864e8 100644
--- a/test/cctest/wasm/test-run-wasm-64.cc
+++ b/test/cctest/wasm/test-run-wasm-64.cc
@@ -1245,7 +1245,7 @@ WASM_EXEC_TEST(I64ReinterpretF64) {
 
   FOR_INT32_INPUTS(i) {
     int64_t expected = static_cast<int64_t>(*i) * 0x300010001;
-    module.WriteMemory(&memory[0], expected);
+    memory[0] = expected;
     CHECK_EQ(expected, r.Call());
   }
 }
@@ -1264,7 +1264,7 @@ WASM_EXEC_TEST(F64ReinterpretI64) {
   FOR_INT32_INPUTS(i) {
     int64_t expected = static_cast<int64_t>(*i) * 0x300010001;
     CHECK_EQ(expected, r.Call(expected));
-    CHECK_EQ(expected, module.ReadMemory<int64_t>(&memory[0]));
+    CHECK_EQ(expected, memory[0]);
   }
 }
 
@@ -1277,13 +1277,13 @@ WASM_EXEC_TEST(LoadMemI64) {
 
   BUILD(r, WASM_LOAD_MEM(MachineType::Int64(), WASM_I8(0)));
 
-  module.WriteMemory<int64_t>(&memory[0], 0xaabbccdd00112233LL);
+  memory[0] = 0xaabbccdd00112233LL;
   CHECK_EQ(0xaabbccdd00112233LL, r.Call());
 
-  module.WriteMemory<int64_t>(&memory[0], 0x33aabbccdd001122LL);
+  memory[0] = 0x33aabbccdd001122LL;
   CHECK_EQ(0x33aabbccdd001122LL, r.Call());
 
-  module.WriteMemory<int64_t>(&memory[0], 77777777);
+  memory[0] = 77777777;
   CHECK_EQ(77777777, r.Call());
 }
 
@@ -1298,13 +1298,13 @@ WASM_EXEC_TEST(LoadMemI64_alignment) {
     BUILD(r,
           WASM_LOAD_MEM_ALIGNMENT(MachineType::Int64(), WASM_I8(0), alignment));
 
-    module.WriteMemory<int64_t>(&memory[0], 0xaabbccdd00112233LL);
+    memory[0] = 0xaabbccdd00112233LL;
     CHECK_EQ(0xaabbccdd00112233LL, r.Call());
 
-    module.WriteMemory<int64_t>(&memory[0], 0x33aabbccdd001122LL);
+    memory[0] = 0x33aabbccdd001122LL;
     CHECK_EQ(0x33aabbccdd001122LL, r.Call());
 
-    module.WriteMemory<int64_t>(&memory[0], 77777777);
+    memory[0] = 77777777;
     CHECK_EQ(77777777, r.Call());
   }
 }
@@ -1338,7 +1338,7 @@ WASM_EXEC_TEST(MemI64_Sum) {
     module.RandomizeMemory(i * 33);
     uint64_t expected = 0;
     for (size_t j = kNumElems - 1; j > 0; j--) {
-      expected += module.ReadMemory(&memory[j]);
+      expected += memory[j];
     }
     uint64_t result = r.Call(8 * (kNumElems - 1));
     CHECK_EQ(expected, result);
@@ -1355,10 +1355,10 @@ WASM_EXEC_TEST(StoreMemI64_alignment) {
     BUILD(r, WASM_STORE_MEM_ALIGNMENT(MachineType::Int64(), WASM_ZERO, i,
                                       WASM_GET_LOCAL(0)));
     module.RandomizeMemory(1111);
-    module.WriteMemory<int64_t>(&memory[0], 0);
+    memory[0] = 0;
 
     CHECK_EQ(kWritten, r.Call(kWritten));
-    CHECK_EQ(kWritten, module.ReadMemory(&memory[0]));
+    CHECK_EQ(kWritten, memory[0]);
   }
 }
 
@@ -1376,7 +1376,7 @@ WASM_EXEC_TEST(I64Global) {
                                   WASM_I64_SCONVERT_I32(WASM_GET_LOCAL(0)))),
               WASM_ZERO));
 
-  module.WriteMemory<int64_t>(global, 0xFFFFFFFFFFFFFFFFLL);
+  *global = 0xFFFFFFFFFFFFFFFFLL;
   for (int i = 9; i < 444444; i += 111111) {
     int64_t expected = *global & i;
     r.Call(i);
diff --git a/test/cctest/wasm/test-run-wasm.cc b/test/cctest/wasm/test-run-wasm.cc
index 55eb008ad01..f41a8b27229 100644
--- a/test/cctest/wasm/test-run-wasm.cc
+++ b/test/cctest/wasm/test-run-wasm.cc
@@ -987,7 +987,7 @@ WASM_EXEC_TEST(F32ReinterpretI32) {
 
   FOR_INT32_INPUTS(i) {
     int32_t expected = *i;
-    module.WriteMemory(&memory[0], expected);
+    memory[0] = expected;
     CHECK_EQ(expected, r.Call());
   }
 }
@@ -1005,7 +1005,7 @@ WASM_EXEC_TEST(I32ReinterpretF32) {
   FOR_INT32_INPUTS(i) {
     int32_t expected = *i;
     CHECK_EQ(107, r.Call(expected));
-    CHECK_EQ(expected, module.ReadMemory(&memory[0]));
+    CHECK_EQ(expected, memory[0]);
   }
 }
 
@@ -1019,7 +1019,7 @@ WASM_EXEC_TEST(ReturnStore) {
 
   FOR_INT32_INPUTS(i) {
     int32_t expected = *i;
-    module.WriteMemory(&memory[0], expected);
+    memory[0] = expected;
     CHECK_EQ(expected, r.Call());
   }
 }
@@ -1309,13 +1309,13 @@ WASM_EXEC_TEST(LoadMemI32) {
 
   BUILD(r, WASM_LOAD_MEM(MachineType::Int32(), WASM_I8(0)));
 
-  module.WriteMemory(&memory[0], 99999999);
+  memory[0] = 99999999;
   CHECK_EQ(99999999, r.Call(0));
 
-  module.WriteMemory(&memory[0], 88888888);
+  memory[0] = 88888888;
   CHECK_EQ(88888888, r.Call(0));
 
-  module.WriteMemory(&memory[0], 77777777);
+  memory[0] = 77777777;
   CHECK_EQ(77777777, r.Call(0));
 }
 
@@ -1329,14 +1329,14 @@ WASM_EXEC_TEST(LoadMemI32_alignment) {
     BUILD(r,
           WASM_LOAD_MEM_ALIGNMENT(MachineType::Int32(), WASM_I8(0), alignment));
 
-    module.WriteMemory(&memory[0], 0x1a2b3c4d);
+    memory[0] = 0x1a2b3c4d;
     CHECK_EQ(0x1a2b3c4d, r.Call(0));
 
-    module.WriteMemory(&memory[0], 0x5e6f7a8b);
+    memory[0] = 0x5e6f7a8b;
     CHECK_EQ(0x5e6f7a8b, r.Call(0));
 
-    module.WriteMemory(&memory[0], 0x7ca0b1c2);
-    CHECK_EQ(0x7ca0b1c2, r.Call(0));
+    memory[0] = 0x9ca0b1c2;
+    CHECK_EQ(0x9ca0b1c2, r.Call(0));
   }
 }
 
@@ -1348,7 +1348,7 @@ WASM_EXEC_TEST(LoadMemI32_oob) {
 
   BUILD(r, WASM_LOAD_MEM(MachineType::Int32(), WASM_GET_LOCAL(0)));
 
-  module.WriteMemory(&memory[0], 88888888);
+  memory[0] = 88888888;
   CHECK_EQ(88888888, r.Call(0u));
   for (uint32_t offset = 29; offset < 40; ++offset) {
     CHECK_TRAP(r.Call(offset));
@@ -1393,18 +1393,18 @@ WASM_EXEC_TEST(LoadMemI32_offset) {
 
   BUILD(r, WASM_LOAD_MEM_OFFSET(MachineType::Int32(), 4, WASM_GET_LOCAL(0)));
 
-  module.WriteMemory(&memory[0], 66666666);
-  module.WriteMemory(&memory[1], 77777777);
-  module.WriteMemory(&memory[2], 88888888);
-  module.WriteMemory(&memory[3], 99999999);
+  memory[0] = 66666666;
+  memory[1] = 77777777;
+  memory[2] = 88888888;
+  memory[3] = 99999999;
   CHECK_EQ(77777777, r.Call(0));
   CHECK_EQ(88888888, r.Call(4));
   CHECK_EQ(99999999, r.Call(8));
 
-  module.WriteMemory(&memory[0], 11111111);
-  module.WriteMemory(&memory[1], 22222222);
-  module.WriteMemory(&memory[2], 33333333);
-  module.WriteMemory(&memory[3], 44444444);
+  memory[0] = 11111111;
+  memory[1] = 22222222;
+  memory[2] = 33333333;
+  memory[3] = 44444444;
   CHECK_EQ(22222222, r.Call(0));
   CHECK_EQ(33333333, r.Call(4));
   CHECK_EQ(44444444, r.Call(8));
@@ -1468,7 +1468,7 @@ WASM_EXEC_TEST(StoreMemI32_alignment) {
     memory[0] = 0;
 
     CHECK_EQ(kWritten, r.Call(kWritten));
-    CHECK_EQ(kWritten, module.ReadMemory(&memory[0]));
+    CHECK_EQ(kWritten, memory[0]);
   }
 }
 
@@ -1483,15 +1483,15 @@ WASM_EXEC_TEST(StoreMemI32_offset) {
 
   for (int i = 0; i < 2; ++i) {
     module.RandomizeMemory(1111);
-    module.WriteMemory(&memory[0], 66666666);
-    module.WriteMemory(&memory[1], 77777777);
-    module.WriteMemory(&memory[2], 88888888);
-    module.WriteMemory(&memory[3], 99999999);
+    memory[0] = 66666666;
+    memory[1] = 77777777;
+    memory[2] = 88888888;
+    memory[3] = 99999999;
     CHECK_EQ(kWritten, r.Call(i * 4));
-    CHECK_EQ(66666666, module.ReadMemory(&memory[0]));
-    CHECK_EQ(i == 0 ? kWritten : 77777777, module.ReadMemory(&memory[1]));
-    CHECK_EQ(i == 1 ? kWritten : 88888888, module.ReadMemory(&memory[2]));
-    CHECK_EQ(i == 2 ? kWritten : 99999999, module.ReadMemory(&memory[3]));
+    CHECK_EQ(66666666, memory[0]);
+    CHECK_EQ(i == 0 ? kWritten : 77777777, memory[1]);
+    CHECK_EQ(i == 1 ? kWritten : 88888888, memory[2]);
+    CHECK_EQ(i == 2 ? kWritten : 99999999, memory[3]);
   }
 }
 
@@ -1534,7 +1534,7 @@ WASM_EXEC_TEST(LoadMemI32_P) {
   BUILD(r, WASM_LOAD_MEM(MachineType::Int32(), WASM_GET_LOCAL(0)));
 
   for (int i = 0; i < kNumElems; ++i) {
-    CHECK_EQ(module.ReadMemory(&memory[i]), r.Call(i * 4));
+    CHECK_EQ(memory[i], r.Call(i * 4));
   }
 }
 
@@ -1563,7 +1563,7 @@ WASM_EXEC_TEST(MemI32_Sum) {
     module.RandomizeMemory(i * 33);
     uint32_t expected = 0;
     for (size_t j = kNumElems - 1; j > 0; --j) {
-      expected += module.ReadMemory(&memory[j]);
+      expected += memory[j];
     }
     uint32_t result = r.Call(4 * (kNumElems - 1));
     CHECK_EQ(expected, result);
@@ -1590,11 +1590,11 @@ WASM_EXEC_TEST(MemF32_Sum) {
   TestingModule module(execution_mode);
   module.AddMemoryElems<float>(kSize);
   float* buffer = module.raw_mem_start<float>();
-  module.WriteMemory(&buffer[0], -99.25f);
-  module.WriteMemory(&buffer[1], -888.25f);
-  module.WriteMemory(&buffer[2], -77.25f);
-  module.WriteMemory(&buffer[3], 66666.25f);
-  module.WriteMemory(&buffer[4], 5555.25f);
+  buffer[0] = -99.25;
+  buffer[1] = -888.25;
+  buffer[2] = -77.25;
+  buffer[3] = 66666.25;
+  buffer[4] = 5555.25;
   WasmRunner<int32_t> r(&module, MachineType::Int32());
   const byte kSum = r.AllocateLocal(kAstF32);
 
@@ -1614,8 +1614,8 @@ WASM_EXEC_TEST(MemF32_Sum) {
                WASM_GET_LOCAL(0)));
 
   CHECK_EQ(0, r.Call(4 * (kSize - 1)));
-  CHECK_NE(-99.25f, module.ReadMemory(&buffer[0]));
-  CHECK_EQ(71256.0f, module.ReadMemory(&buffer[0]));
+  CHECK_NE(-99.25, buffer[0]);
+  CHECK_EQ(71256.0f, buffer[0]);
 }
 
 template <typename T>
@@ -1623,9 +1623,9 @@ T GenerateAndRunFold(WasmExecutionMode execution_mode, WasmOpcode binop,
                      T* buffer, uint32_t size, LocalType astType,
                      MachineType memType) {
   TestingModule module(execution_mode);
-  T* memory = module.AddMemoryElems<T>(size);
+  module.AddMemoryElems<T>(size);
   for (uint32_t i = 0; i < size; ++i) {
-    module.WriteMemory(&memory[i], buffer[i]);
+    module.raw_mem_start<T>()[i] = buffer[i];
   }
   WasmRunner<int32_t> r(&module, MachineType::Int32());
   const byte kAccum = r.AllocateLocal(astType);
@@ -1646,7 +1646,7 @@ T GenerateAndRunFold(WasmExecutionMode execution_mode, WasmOpcode binop,
           WASM_STORE_MEM(memType, WASM_ZERO, WASM_GET_LOCAL(kAccum)),
           WASM_GET_LOCAL(0)));
   r.Call(static_cast<int>(sizeof(T) * (size - 1)));
-  return module.ReadMemory(&memory[0]);
+  return module.raw_mem_at<double>(0);
 }
 
 WASM_EXEC_TEST(MemF64_Mul) {
@@ -2039,11 +2039,11 @@ WASM_EXEC_TEST(CallF64StackParameter) {
 WASM_EXEC_TEST(CallVoid) {
   const byte kMemOffset = 8;
   const int32_t kElemNum = kMemOffset / sizeof(int32_t);
-  const int32_t kExpected = 414444;
+  const int32_t kExpected = -414444;
   // Build the target function.
   TestSignatures sigs;
   TestingModule module(execution_mode);
-  int32_t* memory = module.AddMemoryElems<int32_t>(16 / sizeof(int32_t));
+  module.AddMemory(16);
   module.RandomizeMemory();
   WasmFunctionCompiler t(sigs.v_v(), &module);
   BUILD(t, WASM_STORE_MEM(MachineType::Int32(), WASM_I8(kMemOffset),
@@ -2057,8 +2057,7 @@ WASM_EXEC_TEST(CallVoid) {
 
   int32_t result = r.Call();
   CHECK_EQ(kExpected, result);
-  CHECK_EQ(static_cast<int64_t>(kExpected),
-           static_cast<int64_t>(module.ReadMemory(&memory[kElemNum])));
+  CHECK_EQ(kExpected, module.raw_mem_start<int32_t>()[kElemNum]);
 }
 
 WASM_EXEC_TEST(Call_Int32Add) {
@@ -2115,15 +2114,14 @@ WASM_EXEC_TEST(Call_Float64Sub) {
 
   FOR_FLOAT64_INPUTS(i) {
     FOR_FLOAT64_INPUTS(j) {
-      module.WriteMemory(&memory[0], *i);
-      module.WriteMemory(&memory[1], *j);
+      memory[0] = *i;
+      memory[1] = *j;
       double expected = *i - *j;
       CHECK_EQ(107, r.Call());
-
       if (expected != expected) {
-        CHECK(module.ReadMemory(&memory[0]) != module.ReadMemory(&memory[0]));
+        CHECK(memory[0] != memory[0]);
       } else {
-        CHECK_EQ(expected, module.ReadMemory(&memory[0]));
+        CHECK_EQ(expected, memory[0]);
       }
     }
   }
diff --git a/test/cctest/wasm/wasm-run-utils.h b/test/cctest/wasm/wasm-run-utils.h
index 1fb49ed4fab..2152112ae75 100644
--- a/test/cctest/wasm/wasm-run-utils.h
+++ b/test/cctest/wasm/wasm-run-utils.h
@@ -139,22 +139,14 @@ class TestingModule : public ModuleEnv {
   template <typename T>
   T raw_mem_at(int i) {
     DCHECK(instance->mem_start);
-    return ReadMemory(&(reinterpret_cast<T*>(instance->mem_start)[i]));
+    return reinterpret_cast<T*>(instance->mem_start)[i];
   }
 
   template <typename T>
   T raw_val_at(int i) {
-    return ReadMemory(reinterpret_cast<T*>(instance->mem_start + i));
-  }
-
-  template <typename T>
-  void WriteMemory(T* p, T val) {
-    WriteLittleEndianValue<T>(p, val);
-  }
-
-  template <typename T>
-  T ReadMemory(T* p) {
-    return ReadLittleEndianValue<T>(p);
+    T val;
+    memcpy(&val, reinterpret_cast<void*>(instance->mem_start + i), sizeof(T));
+    return val;
   }
 
   // Zero-initialize the memory.