[turbofan] Fewer gap moves for tail calls

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index ced7c4f369a91221cb8176b4c4a1c27155d5a60d..70e043d82d9359f1f2eb9221bd4bf01f97e39fe7 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -507,12 +507,11 @@ void InstructionSelector::InitializeCallBuffer(Node* call, CallBuffer* buffer,
   }
   DCHECK_EQ(input_count, buffer->instruction_args.size() + pushed_count -
                              buffer->frame_state_value_count());
-  if (call_tail && stack_param_delta != 0) {
-    // For tail calls that change the size of their parameter list, move the
-    // saved caller return address, parent frame pointer and parent constant
-    // pool pointer to just above the parameters.
-
-    // Return address
+  if (V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK && call_tail &&
+      stack_param_delta != 0) {
+    // For tail calls that change the size of their parameter list and keep
+    // their return address on the stack, move the return address to just above
+    // the parameters.
     LinkageLocation saved_return_location =
         LinkageLocation::ForSavedCallerReturnAddress();
     InstructionOperand return_address =
@@ -520,26 +519,6 @@ void InstructionSelector::InitializeCallBuffer(Node* call, CallBuffer* buffer,
                                  saved_return_location, stack_param_delta),
                              saved_return_location);
     buffer->instruction_args.push_back(return_address);
-
-    // Parent frame pointer
-    LinkageLocation saved_frame_location =
-        LinkageLocation::ForSavedCallerFramePtr();
-    InstructionOperand saved_frame =
-        g.UsePointerLocation(LinkageLocation::ConvertToTailCallerLocation(
-                                 saved_frame_location, stack_param_delta),
-                             saved_frame_location);
-    buffer->instruction_args.push_back(saved_frame);
-
-    if (V8_EMBEDDED_CONSTANT_POOL) {
-      // Constant pool pointer
-      LinkageLocation saved_cp_location =
-          LinkageLocation::ForSavedCallerConstantPool();
-      InstructionOperand saved_cp =
-          g.UsePointerLocation(LinkageLocation::ConvertToTailCallerLocation(
-                                   saved_cp_location, stack_param_delta),
-                               saved_cp_location);
-      buffer->instruction_args.push_back(saved_cp);
-    }
   }
 }