Implement optional turbofan UnalignedLoad and UnalignedStore operators

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index c4bde203fa71de431a8f4c0d7382348b3928504e..e68e8dc2632459fceb0a3d9c707c930e1b0dff18 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -2266,9 +2266,9 @@ void WasmGraphBuilder::BoundsCheckMem(MachineType memtype, Node* index,
   trap_->AddTrapIfFalse(kTrapMemOutOfBounds, cond);
 }
 
-
 Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
-                                Node* index, uint32_t offset) {
+                                Node* index, uint32_t offset,
+                                uint32_t alignment) {
   Node* load;
 
   if (module_ && module_->asm_js()) {
@@ -2280,8 +2280,15 @@ Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
   } else {
     // WASM semantics throw on OOB. Introduce explicit bounds check.
     BoundsCheckMem(memtype, index, offset);
-    load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
-                            MemBuffer(offset), index, *effect_, *control_);
+    bool aligned = alignment >= ElementSizeLog2Of(memtype.representation());
+    if (aligned ||
+        !jsgraph()->machine()->UnalignedLoad(memtype).IsSupported()) {
+      load = graph()->NewNode(jsgraph()->machine()->Load(memtype),
+                              MemBuffer(offset), index, *effect_, *control_);
+    } else {
+      load = graph()->NewNode(jsgraph()->machine()->UnalignedLoad(memtype).op(),
+                              MemBuffer(offset), index, *effect_, *control_);
+    }
   }
 
   *effect_ = load;
@@ -2302,9 +2309,9 @@ Node* WasmGraphBuilder::LoadMem(wasm::LocalType type, MachineType memtype,
   return load;
 }
 
-
 Node* WasmGraphBuilder::StoreMem(MachineType memtype, Node* index,
-                                 uint32_t offset, Node* val) {
+                                 uint32_t offset, uint32_t alignment,
+                                 Node* val) {
   Node* store;
   if (module_ && module_->asm_js()) {
     // asm.js semantics use CheckedStore (i.e. ignore OOB writes).
@@ -2316,10 +2323,21 @@ Node* WasmGraphBuilder::StoreMem(MachineType memtype, Node* index,
   } else {
     // WASM semantics throw on OOB. Introduce explicit bounds check.
     BoundsCheckMem(memtype, index, offset);
-    StoreRepresentation rep(memtype.representation(), kNoWriteBarrier);
-    store =
-        graph()->NewNode(jsgraph()->machine()->Store(rep), MemBuffer(offset),
-                         index, val, *effect_, *control_);
+    bool aligned = alignment >= ElementSizeLog2Of(memtype.representation());
+    if (aligned ||
+        !jsgraph()
+             ->machine()
+             ->UnalignedStore(memtype.representation())
+             .IsSupported()) {
+      StoreRepresentation rep(memtype.representation(), kNoWriteBarrier);
+      store =
+          graph()->NewNode(jsgraph()->machine()->Store(rep), MemBuffer(offset),
+                           index, val, *effect_, *control_);
+    } else {
+      store = graph()->NewNode(
+          jsgraph()->machine()->UnalignedStore(memtype.representation()).op(),
+          MemBuffer(offset), index, val, *effect_, *control_);
+    }
   }
   *effect_ = store;
   return store;