https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105549
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Christophe Lyon <cl...@gcc.gnu.org>: https://gcc.gnu.org/g:f593bfa059fbd2c145d8dd2bae4860959e9e55fe commit r12-9067-gf593bfa059fbd2c145d8dd2bae4860959e9e55fe Author: Christophe Lyon <christophe.l...@arm.com> Date: Tue Jun 14 21:08:33 2022 +0000 aarch64: fix warning emission for ABI break since GCC 9.1 While looking at PR 105549, which is about fixing the ABI break introduced in GCC 9.1 in parameter alignment with bit-fields, we noticed that the GCC 9.1 warning is not emitted in all the cases where it should be. This patch fixes that and the next patch in the series fixes the GCC 9.1 break. We split this into two patches since patch #2 introduces a new ABI break starting with GCC 13.1. This way, patch #1 can be back-ported to release branches if needed to fix the GCC 9.1 warning issue. The main idea is to add a new global boolean that indicates whether we're expanding the start of a function, so that aarch64_layout_arg can emit warnings for callees as well as callers. This removes the need for aarch64_function_arg_boundary to warn (with its incomplete information). However, in the first patch there are still cases where we emit warnings were we should not; this is fixed in patch #2 where we can distinguish between GCC 9.1 and GCC.13.1 ABI breaks properly. The fix in aarch64_function_arg_boundary (replacing & with &&) looks like an oversight of a previous commit in this area which changed 'abi_break' from a boolean to an integer. We also take the opportunity to fix the comment above aarch64_function_arg_alignment since the value of the abi_break parameter was changed in a previous commit, no longer matching the description. 2022-11-28 Christophe Lyon <christophe.l...@arm.com> Richard Sandiford <richard.sandif...@arm.com> gcc/ChangeLog: * config/aarch64/aarch64.cc (aarch64_function_arg_alignment): Fix comment. (aarch64_layout_arg): Factorize warning conditions. (aarch64_function_arg_boundary): Fix typo. * function.cc (currently_expanding_function_start): New variable. (expand_function_start): Handle currently_expanding_function_start. * function.h (currently_expanding_function_start): Declare. gcc/testsuite/ChangeLog: * gcc.target/aarch64/bitfield-abi-warning-align16-O2.c: New test. * gcc.target/aarch64/bitfield-abi-warning-align16-O2-extra.c: New test. * gcc.target/aarch64/bitfield-abi-warning-align32-O2.c: New test. * gcc.target/aarch64/bitfield-abi-warning-align32-O2-extra.c: New test. * gcc.target/aarch64/bitfield-abi-warning-align8-O2.c: New test. * gcc.target/aarch64/bitfield-abi-warning.h: New test. * g++.target/aarch64/bitfield-abi-warning-align16-O2.C: New test. * g++.target/aarch64/bitfield-abi-warning-align16-O2-extra.C: New test. * g++.target/aarch64/bitfield-abi-warning-align32-O2.C: New test. * g++.target/aarch64/bitfield-abi-warning-align32-O2-extra.C: New test. * g++.target/aarch64/bitfield-abi-warning-align8-O2.C: New test. * g++.target/aarch64/bitfield-abi-warning.h: New test. (cherry picked from commit 3df1a115be22caeab3ffe7afb12e71adb54ff132)