https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95646
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by SRINATH PARVATHANENI <sripa...@gcc.gnu.org>: https://gcc.gnu.org/g:f1370bf2aa6cac4ab6235d8480b0a5d4f85ca54e commit r10-9806-gf1370bf2aa6cac4ab6235d8480b0a5d4f85ca54e Author: Srinath Parvathaneni <srinath.parvathan...@arm.com> Date: Thu May 6 10:46:45 2021 +0100 arm: Do not clobber callee saved registers with CMSE. As reported in bugzilla when the -mcmse option is used while compiling for size (-Os) with a thumb-1 target the generated code will clear the registers r7-r10. These however are callee saved and should be preserved accross ABI boundaries. The reason this happens is because these registers are made "fixed" when optimising for size with Thumb-1 in a way to make sure they are not used, as pushing and popping hi-registers requires extra moves to and from LO_REGS. To fix this, this patch uses 'callee_saved_reg_p', which accounts for this optimisation, instead of 'call_used_or_fixed_reg_p'. Be aware of 'callee_saved_reg_p''s definition, as it does still take call used registers into account, which aren't callee_saved in my opinion, so it is a rather misnoemer, works in our advantage here though as it does exactly what we need. gcc/ChangeLog: 2020-06-19 Andre Vieira <andre.simoesdiasvie...@arm.com> PR target/95646 * config/arm/arm.c: (cmse_nonsecure_entry_clear_before_return): Use 'callee_saved_reg_p' instead of 'calL_used_or_fixed_reg_p'. gcc/testsuite/ChangeLog: 2020-06-19 Andre Vieira <andre.simoesdiasvie...@arm.com> PR target/95646 * gcc.target/arm/pr95646.c: New test. (cherry picked from commit 5f426554fd804d65509875d706d8b8bc3a48393b)
