On 23/06/2020 21:52, Christophe Lyon wrote:
On Tue, 23 Jun 2020 at 15:28, Andre Vieira (lists)
<andre.simoesdiasvie...@arm.com> wrote:
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?
Hi,
This is not sufficient to skip arm-linux-gnueabi* configs built with
non-default cpu/fpu.
For instance, with arm-linux-gnueabihf --with-cpu=cortex-a9
--with-fpu=neon-fp16 --with-float=hard
I see:
FAIL: gcc.target/arm/pr95646.c (test for excess errors)
Excess errors:
cc1: error: ARMv8-M Security Extensions incompatible with selected FPU
cc1: error: target CPU does not support ARM mode
and the testcase is compiled with -mcpu=cortex-m23 -mcmse -Os
Resending as I don't think my earlier one made it to the lists (sorry if
you are receiving this double!)
I'm not following this, before I go off and try to reproduce it, what do
you mean by 'the testcase is compiled with -mcpu=cortex-m23 -mcmse -Os'?
These are the options you are seeing in the log file? Surely they should
override the default options? Only thing I can think of is this might
need an extra -mfloat-abi=soft to make sure it overrides the default
float-abi. Could you give that a try?
Cheers,
Andre
Christophe
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.
