On 06/11/15 11:31, Bernd Schmidt wrote:
> On 11/06/2015 12:17 PM, Ramana Radhakrishnan wrote:
>> On 06/11/15 11:08, Bernd Schmidt wrote:
>>> This one is a fix for something that could currently only affect c6x, but I
>>> have code that exposes it on i386.
>>>
>>> When optionally gathering operand info in regrename, we can overflow the
>>> array in certain situations. This can occur when we have a situation where
>>> a value is constructed in multiple small registers and then accessed as a
>>> larger one (CDImode in the testcase I have). In that case we enter the
>>> "superset" path, which fails the involved chains, but the smaller pieces
>>> still all get seen by record_operand_use, and there may be more of them
>>> than MAX_REGS_PER_ADDRESS.
>>>
>>> The following fixes it. Bootstrapped and tested with -frename-registers
>>> enabled at -O1 on x86_64-linux. Ok?
>>>
>>>
>>> Bernd
>>
>> This sounds like it will fix http://gcc.gnu.org/PR66785 ...
>
> Ah, I didn't realize something else was using this functionality:
>
> gcc/config/aarch64/cortex-a57-fma-steering.c
> 1025: regrename_init (true);
>
> Yeah, the description of that bug makes it sound like the same issue.
Yeah looks like the ICE goes away with a quick spin - I've not done any deeper
analysis but that looks like a fix.
I'll take the opportunity to point out gcc11{3-6} if you need an aarch64
machine on the compile farm if you wanted access to one.
regards
Ramana
>
>
> Bernd
