[turbofan] Reland of `Add alignment parameter to StackSlot operator`

src/compiler/mips64/instruction-selector-mips64.cc

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index 0aa4f1837b601f8a5b2fce152f92febfac50425d..cc1323162ca3a6c3f86704bfc52a1e73ef92ea7f 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -352,6 +352,17 @@ static void VisitBinop(InstructionSelector* selector, Node* node,
   VisitBinop(selector, node, opcode, false, kArchNop);
 }
 
+void InstructionSelector::VisitStackSlot(Node* node) {
+  StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
+  int alignment = rep.alignment();
+  int slot = frame_->AllocateSpillSlot(rep.size(), alignment);
+  OperandGenerator g(this);
+
+  Emit(kArchStackSlot, g.DefineAsRegister(node),
+       sequence()->AddImmediate(Constant(slot)),
+       sequence()->AddImmediate(Constant(alignment)), 0, nullptr);
+}
+
 void EmitLoad(InstructionSelector* selector, Node* node, InstructionCode opcode,
               Node* output = nullptr) {
   Mips64OperandGenerator g(selector);