[turbofan] Various fixes to allow unboxed doubles as arguments in registers and on the stack.

src/compiler/register-allocator.cc

Index: src/compiler/register-allocator.cc
diff --git a/src/compiler/register-allocator.cc b/src/compiler/register-allocator.cc
index 5bf858a86cf6e7551ce7a033603cc7c17990cbe2..5263aeccf95145371b6cf158a1929a857b42c3af 100644
--- a/src/compiler/register-allocator.cc
+++ b/src/compiler/register-allocator.cc
@@ -1102,8 +1102,11 @@ InstructionOperand* ConstraintBuilder::AllocateFixed(
     machine_type = data()->MachineTypeFor(virtual_register);
   }
   if (operand->HasFixedSlotPolicy()) {
-    allocated = AllocatedOperand(AllocatedOperand::STACK_SLOT, machine_type,
-                                 operand->fixed_slot_index());
+    AllocatedOperand::AllocatedKind kind =
+        IsFloatingPoint(machine_type) ? AllocatedOperand::DOUBLE_STACK_SLOT
+                                      : AllocatedOperand::STACK_SLOT;
+    allocated =
+        AllocatedOperand(kind, machine_type, operand->fixed_slot_index());
   } else if (operand->HasFixedRegisterPolicy()) {
     allocated = AllocatedOperand(AllocatedOperand::REGISTER, machine_type,
                                  operand->fixed_register_index());