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

src/compiler/mips/instruction-selector-mips.cc

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index eaa17af7a07c44f714007609b294671736e309b4..415c0c5252c5600a4629a6cbc819cbb0ccdd9f35 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -1542,6 +1542,20 @@ InstructionSelector::SupportedMachineOperatorFlags() {
          MachineOperatorBuilder::kFloat32RoundTiesEven;
 }
 
+// static
+MachineOperatorBuilder::AlignmentRequirements
+InstructionSelector::AlignmentRequirements() {
+  if (IsMipsArchVariant(kMips32r6)) {
+    return MachineOperatorBuilder::AlignmentRequirements::
+        FullUnalignedAccessSupport();
+  } else {
+    DCHECK(IsMipsArchVariant(kLoongson) || IsMipsArchVariant(kMips32r1) ||
+           IsMipsArchVariant(kMips32r2));
+    return MachineOperatorBuilder::AlignmentRequirements::
+        NoUnalignedAccessSupport();
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8