Implement UnalignedLoad and UnalignedStore in WASM using LoadByte/Shift/Or and StoreByte/Shift/And.

src/wasm/ast-decoder.cc

Index: src/wasm/ast-decoder.cc
diff --git a/src/wasm/ast-decoder.cc b/src/wasm/ast-decoder.cc
index 1f361b9998dd63c8243f660226f18624065861d5..65d1079b3112c7bf4b082cc2000513b3f2895a8b 100644
--- a/src/wasm/ast-decoder.cc
+++ b/src/wasm/ast-decoder.cc
@@ -1105,8 +1105,8 @@ class SR_WasmDecoder : public WasmDecoder {
   int DecodeLoadMem(LocalType type, MachineType mem_type) {
     MemoryAccessOperand operand(this, pc_);
     Value index = Pop(0, kAstI32);
-    TFNode* node =
-        BUILD(LoadMem, type, mem_type, index.node, operand.offset, position());
+    TFNode* node = BUILD(LoadMem, type, mem_type, index.node, operand.offset,
+                         operand.alignment, position());
     Push(type, node);
     return 1 + operand.length;
   }
@@ -1115,7 +1115,8 @@ class SR_WasmDecoder : public WasmDecoder {
     MemoryAccessOperand operand(this, pc_);
     Value val = Pop(1, type);
     Value index = Pop(0, kAstI32);
-    BUILD(StoreMem, mem_type, index.node, operand.offset, val.node, position());
+    BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment,
+          val.node, position());
     Push(type, val.node);
     return 1 + operand.length;
   }