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

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 4e9f99fb9c3f5a51299c9a21a3f64abdfaa732ea..0cdbd5f6d0c4438791c2042361b4d7e5f8ea6c76 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -99,12 +99,9 @@ class PPCOperandConverter final : public InstructionOperandConverter {
 
   MemOperand ToMemOperand(InstructionOperand* op) const {
     DCHECK(op != NULL);
-    DCHECK(!op->IsRegister());
-    DCHECK(!op->IsDoubleRegister());
     DCHECK(op->IsStackSlot() || op->IsDoubleStackSlot());
-    // The linkage computes where all spill slots are located.
-    FrameOffset offset = linkage()->GetFrameOffset(
-        AllocatedOperand::cast(op)->index(), frame(), 0);
+    FrameOffset offset =
+        linkage()->GetFrameOffset(AllocatedOperand::cast(op)->index(), frame());
     return MemOperand(offset.from_stack_pointer() ? sp : fp, offset.offset());
   }
 };
@@ -1360,6 +1357,7 @@ void CodeGenerator::AssemblePrologue() {
 void CodeGenerator::AssembleReturn() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int stack_slots = frame()->GetSpillSlotCount();
+  int pop_count = static_cast<int>(descriptor->StackParameterCount());
   if (descriptor->kind() == CallDescriptor::kCallAddress) {
     if (frame()->GetRegisterSaveAreaSize() > 0) {
       // Remove this frame's spill slots first.
@@ -1378,21 +1376,17 @@ void CodeGenerator::AssembleReturn() {
       const RegList saves = descriptor->CalleeSavedRegisters() & ~frame_saves;
       __ MultiPop(saves);
     }
-    __ LeaveFrame(StackFrame::MANUAL);
-    __ Ret();
   } else if (descriptor->IsJSFunctionCall() || needs_frame_) {
     // Canonicalize JSFunction return sites for now.
     if (return_label_.is_bound()) {
       __ b(&return_label_);
+      return;
     } else {
       __ bind(&return_label_);
-      int pop_count = static_cast<int>(descriptor->StackParameterCount());
-      __ LeaveFrame(StackFrame::MANUAL, pop_count * kPointerSize);
-      __ Ret();
     }
-  } else {
-    __ Ret();
   }
+  __ LeaveFrame(StackFrame::MANUAL, pop_count * kPointerSize);
+  __ Ret();
 }