> -----Original Message----- > From: Andre Vieira (lists) <andre.simoesdiasvie...@arm.com> > Sent: 23 June 2020 14:28 > To: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; gcc-patches@gcc.gnu.org > Subject: Re: [PATCH][GCC][Arm] PR target/95646: Do not clobber callee saved > registers with CMSE > > On 23/06/2020 13:10, Kyrylo Tkachov wrote: > > > >> -----Original Message----- > >> From: Andre Vieira (lists) <andre.simoesdiasvie...@arm.com> > >> Sent: 22 June 2020 09:52 > >> To: gcc-patches@gcc.gnu.org > >> Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com> > >> Subject: [PATCH][GCC][Arm] PR target/95646: Do not clobber callee saved > >> registers with CMSE > >> > >> Hi, > >> > >> 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. > >> > >> Regression tested on arm-none-eabi. > >> > >> Is this OK for trunk? (Will eventually backport to previous versions if > >> stable.) > > Ok. > > Thanks, > > Kyrill > As I was getting ready to push this I noticed I didn't add any skip-ifs > to prevent this failing with specific target options. So here's a new > version with those. > > Still OK? >
Ok. Thanks, Kyrill > Cheers, > Andre > > > >> Cheers, > >> Andre > >> > >> gcc/ChangeLog: > >> 2020-06-22 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: > >> 2020-06-22 Andre Vieira <andre.simoesdiasvie...@arm.com> > >> > >> PR target/95646 > >> * gcc.target/arm/pr95646.c: New test.
