[PATCH] arm: Ignore --with-mode when CPU only supports one instruction set.

[Richard Earnshaw (lists)]

On 03/03/2021 14:11, Christophe Lyon via Gcc-patches wrote:
> On Wed, 3 Mar 2021 at 14:55, Richard Earnshaw (lists)
> <Richard.Earnshaw@arm.com> wrote:
>>
>> Hopefully this change will reduce the number of times Christophe is
>> needing to tweak the testsuite.
>>
> 
> Thanks!
> 
> I guess this means we can now do some cleanup in the testsuite?
> Did you have a quick look at the amount of tests involved?
> 

No, I wasn't expecting to change the existing tests again where you've
already done this.  But hopefully you won't need to do any more changes
for this reason in future.

R.

> Christophe
> 
>> --------------
>>
>> Arm processors can support up to two instruction sets.  Some early
>> cores only support the traditional A32 (Arm) instructions, while some
>> more recent devices only support T32 (Thumb) instructions.
>>
>> When configuring the compiler, --with-mode can be used to select the
>> default instruction set to target if the user has not made an explicit
>> choice, but this can cause needless problems if the default is not
>> supported by the requested CPU.
>>
>> To fix this this patch adjusts the way that the --with-mode selection
>> is processed so that it can take into account the selected CPU or
>> architecture and not create a meaningless combination.
>>
>> gcc:
>>         * common/config/arm/arm-common.c: Include configargs.h.
>>         (arm_config_default): New function.
>>         (arm_target_mode): Renamed from arm_target_thumb_only.  Handle
>>         processors that do not support Thumb.  Take into account the
>>         --with-mode configuration setting for selecting the default.
>>         * config/arm/arm.h (OPTION_DEFAULT_SPECS): Remove entry for 'mode'.
>>         (TARGET_MODE_SPEC_FUNCTIONS): Update for function name change.
>> ---
>>  gcc/common/config/arm/arm-common.c | 49 ++++++++++++++++++++++++++----
>>  gcc/config/arm/arm.h               | 10 +++---
>>  2 files changed, 49 insertions(+), 10 deletions(-)
>>
>>