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Re: [PATCH, ARM] Fix PR64453: live high register not saved in function prolog with -Os


On Fri, Jan 23, 2015 at 8:23 AM, Thomas Preud'homme
<thomas.preudhomme@arm.com> wrote:
> Hi Ramana,
>
>> From: Ramana Radhakrishnan [mailto:ramana.gcc@googlemail.com]
>> Sent: Wednesday, January 14, 2015 7:21 PM
>> On Wed, Jan 14, 2015 at 10:20 AM, Thomas Preud'homme
>> <thomas.preudhomme@arm.com> wrote:
>> > When compiling for size, live high registers are not saved in function
>> prolog in ARM backend in Thumb mode. The problem comes from
>> arm_conditional_register_usage setting call_used_regs for all high
>> register to avoid them being allocated. However, this cause prolog to not
>> save these register even if they are used. This patch marks high registers
>> as really needing to be saved in prolog if live, no matter what is the
>> content of call_used_regs.
>> >
>> > ChangeLog entries are as follows:
>> >
>> > gcc/ChangeLog
>> >
>> > 2015-01-12 Thomas Preud'homme thomas.preudhomme@arm.com
>> >
>> >     PR target/64453
>> >     * config/arm/arm.c (callee_saved_reg_p): Define.
>> >     (arm_compute_save_reg0_reg12_mask): Use callee_saved_reg_p
>> to check if
>> >     register is callee saved instead of !call_used_regs[reg].
>> >     (thumb1_compute_save_reg_mask): Likewise.
>> >
>> >
>> > gcc/testsuite/ChangeLog
>> >
>> > 2014-12-31 Thomas Preud'homme thomas.preudhomme@arm.com
>> >
>> >     * gcc.target/arm/pr64453.c: New.
>> >
>> >
>> >
>>
>> OK.
>>
>> Ramana
>
> The patch applies cleanly on GCC 4.8 and 4.9 branches when omitting the cosmetic change
> in arm_conditional_register_usage () which was unintended. I compiled an arm-none-eabi
> GCC cross compiler and ran the testsuite for both backport without any regression.
>
> Is this ok for the 4.8 and 4.9 branches?
>

OK for the branches if no RM objects in 24 hours.

Ramana

> Best regards,
>
> Thomas
>
>
>


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