Building jdk with GCC 9.1+ would generate ton of warnings like "parameter passing for argument of type '...' changed in GCC 9.1".
The message is notifying a potential AArch64 ABI's "bug with the handling of 128-bit bit-fields", see details in the description and inline comments of this GCC patch:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88469
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=268273
https://patches.linaro.org/patch/156615

One of the warning messages looks like:

src/hotspot/share/interpreter/bytecodeUtils.cpp: In member function 'StackSlotAnalysisData StackSlotAnalysisData::merge(StackSlotAnalysisData)':
src/hotspot/share/interpreter/bytecodeUtils.cpp:368:23: note: parameter passing for argument of type 'StackSlotAnalysisData' changed in GCC 9.1
  368 | StackSlotAnalysisData StackSlotAnalysisData::merge(StackSlotAnalysisData other) {
      | ^~~~~~~~~~~~~~~~~~~~~
src/hotspot/share/interpreter/bytecodeUtils.cpp: In member function 'void SimulatedOperandStack::push_raw(StackSlotAnalysisData)':
src/hotspot/share/interpreter/bytecodeUtils.cpp:396:6: note: parameter passing for argument of type 'StackSlotAnalysisData' changed in GCC 9.1
  396 | void SimulatedOperandStack::push_raw(StackSlotAnalysisData slotData) {
      | ^~~~~~~~~~~~~~~~~~~~~
src/hotspot/share/interpreter/bytecodeUtils.cpp: In member function 'void SimulatedOperandStack::push(StackSlotAnalysisData)':
src/hotspot/share/interpreter/bytecodeUtils.cpp:404:6: note: parameter passing for argument of type 'StackSlotAnalysisData' changed in GCC 9.1
  404 | void SimulatedOperandStack::push(StackSlotAnalysisData slotData) {
      | ^~~~~~~~~~~~~~~~~~~~~