void Method::link_method(const methodHandle& h_method, TRAPS) {
  // If the code cache is full, we may reenter this function for the
  // leftover methods that weren't linked.
  if (is_shared()) {
    address entry = Interpreter::entry_for_cds_method(h_method);
    assert(Interpreter::entry_for_cds_method(h_method) == _i2i_entry,
           "should be correctly set during dump time");
    if (adapter() != NULL) {
      return;
    }
    assert(entry == _from_interpreted_entry,
           "should be correctly set during dump time");
  } else if (_i2i_entry != NULL) {
    return;
  }

The "entry" is only used for purposes of some assertions, and Interpreter::entry_for_cds_method(h_method); does not have any side effect - but compilers can't see through into all parts of this call (specifically into abstractInterpreter::method_kind) to prove this and eliminate the code.

That means this simple patch is a small improvement on each method linked from the CDS archive, which has a measurable impact already on Hello World:

diff -r f227e770495f src/hotspot/share/oops/method.cpp
--- a/src/hotspot/share/oops/method.cpp Fri Feb 28 15:30:29 2020 -0800
+++ b/src/hotspot/share/oops/method.cpp Sun Mar 01 19:03:33 2020 +0100
@@ -1175,7 +1175,7 @@
   // If the code cache is full, we may reenter this function for the
   // leftover methods that weren't linked.
   if (is_shared()) {
- address entry = Interpreter::entry_for_cds_method(h_method);
+ NOT_PRODUCT(address entry = Interpreter::entry_for_cds_method(h_method);)
     assert(entry != NULL && entry == _i2i_entry,
            "should be correctly set during dump time");
     if (adapter() != NULL) {

Before:
       111,869,073 instructions # 0.82 insns per cycle ( +- 0.07% )
        22,206,305 branches # 421.885 M/sec ( +- 0.08% )
           764,563 branch-misses # 3.44% of all branches ( +- 0.14% )

After:
      111,399,179 instructions # 0.82 insns per cycle ( +- 0.08% )
        22,055,916 branches # 420.503 M/sec ( +- 0.08% )
           762,839 branch-misses # 3.46% of all branches ( +- 0.16% )