This patch simplifies the handling of EH return. We force the use of the
frame pointer so the return location is always at FP + 8. This means we
can emit a simple volatile access in EH_RETURN_HANDLER_RTX without needing md
patterns, splitters and frame offset calculations. The new implementation also
fixes various bugs in aarch64_final_eh_return_addr, which does not work with
-fomit-frame-pointer, alloca or outgoing arguments.
gcc/
* config/aarch64/aarch64.md (eh_return): Remove pattern and splitter.
* config/aarch64/aarch64.h (AARCH64_EH_STACKADJ_REGNUM): Remove.
(EH_RETURN_HANDLER_RTX): New define.
* config/aarch64/aarch64.c (aarch64_frame_pointer_required):
Force frame pointer in EH return functions.
(aarch64_expand_epilogue): Add barrier for eh_return.
(aarch64_final_eh_return_addr): Remove.
(aarch64_eh_return_handler_rtx): New function.
* config/aarch64/aarch64-protos.h (aarch64_final_eh_return_addr):
Remove.
(aarch64_eh_return_handler_rtx): New prototype.
testsuite/
* gcc.target/aarch64/eh_return.c: New test.