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

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

Index: src/compiler/mips/code-generator-mips.cc
diff --git a/src/compiler/mips/code-generator-mips.cc b/src/compiler/mips/code-generator-mips.cc
index e2ae0bd05dca5f063483f5c5dc3fb224b9263722..a64185c5570e0a6ed9700d4d9677be9485a3c3ab 100644
--- a/src/compiler/mips/code-generator-mips.cc
+++ b/src/compiler/mips/code-generator-mips.cc
@@ -106,12 +106,9 @@ class MipsOperandConverter 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());
   }
 };
@@ -1100,6 +1097,8 @@ void CodeGenerator::AssemblePrologue() {
     __ StubPrologue();
     frame()->SetRegisterSaveAreaSize(
         StandardFrameConstants::kFixedFrameSizeFromFp);
+  } else {
+    frame()->SetPCOnStack(false);
   }
 
   if (info()->is_osr()) {
@@ -1127,6 +1126,7 @@ 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.
@@ -1143,22 +1143,19 @@ void CodeGenerator::AssembleReturn() {
     }
     __ mov(sp, fp);
     __ Pop(ra, fp);
-    __ Ret();
   } else if (descriptor->IsJSFunctionCall() || needs_frame_) {
     // Canonicalize JSFunction return sites for now.
     if (return_label_.is_bound()) {
       __ Branch(&return_label_);
+      return;
     } else {
       __ bind(&return_label_);
       __ mov(sp, fp);
       __ Pop(ra, fp);
-      int pop_count = static_cast<int>(descriptor->StackParameterCount());
-      if (pop_count != 0) {
-        __ DropAndRet(pop_count);
-      } else {
-        __ Ret();
-      }
     }
+  }
+  if (pop_count != 0) {
+    __ DropAndRet(pop_count);
   } else {
     __ Ret();
   }