On 07/24/2014 04:27 PM, Marat Zakirov wrote:
>
> On 07/23/2014 06:23 PM, Marat Zakirov wrote:
>> Hi there!
>>
>> I made a patch which fixes regressions on ARM platforms with disabled 
>> unaligned accesses. The problem is that 'arm_vect_no_misalign' 
>> predicate do not check 'unaligned_access' global variable to 
>> determine whether unaligned access to vector are allowed. This leads 
>> to spurious vect.exp test fails when GCC is configured 
>> --with-specs=%{!munaligned-access:-mno-unaligned-access}.
>>
>> Attached patch fixes ARM predicate and several tests to correctly 
>> handle the issue.
>>
>> The following targets were reg. tested for multiple targets (ARM, 
>> Thumb-1, Thumb-2, x86, x86_64) with and without 
>> -mno-unaligned-access.  Analysis showed patch affects only vect.exp 
>> tests so only vect.exp was tested.
>>
>> For x86, x86_64,  ARM without -mno-unaligned-access, Thumb-2 without 
>> -mno-unaligned-access and Thumb-1 no regressions occured. For 
>> ARM/Thumb2 with -mno-unaligned-access patch fixed most of failures 
>> but triggered some problems (see attached log) for current vect.exp 
>> tests:
>> 1) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61887
>> 2) Some XPASS'es due to unexpected loop versioning (e.g. 
>> gcc.dg/vect/pr33804.c).
>> 3) After predicate fix some passing tests which require unaligned 
>> vector support become NA (this was expected).
>>
> Here is new version of patch and regression log. On the current trunk 
> results are slightly different due to patches for Richard Biener (no 
> UNRESOLVED fails) but some  PASS->XPASS regressions still remain (see 
> attachment):
>
> PASS->XPASS: gcc.dg/vect/if-cvt-stores-vect-ifcvt-18.c 
> scan-tree-dump-times vect "vectorized 1 loops" 1
> PASS->XPASS: gcc.dg/vect/pr33804.c -flto -ffat-lto-objects 
> scan-tree-dump-times vect "vectorized 1 loops" 1
> etc.
>
> These XPASS'es are due to code versioning: current GCC creates 2 
> versions of loop: aligned and misaligned. It's look like they are 
> slightly out of date at lest for ARM.
>

On 07/24/2014 06:50 PM, Ramana Radhakrishnan wrote:
> This is redundant.
>
>> -           || (defined(__ARMEL__) \
>> +           || (defined(__ARM_FEATURE_UNALIGNED) \
>> +               && defined(__ARMEL__) \
>>                  && (!defined(__thumb__) || defined(__thumb2__)))
> As is this line.
>
> I think you can restrict the check to defined(__ARM_FEATURE_UNALIGNED)
> && defined(__ARMEL__)
>
>   __ARM_FEATURE_UNALIGNED should tell you whether unaligned access is
> allowed or not, therefore you should no longer require any specific
> "architectural" checks.
>
>
>>          #error FOO
>>          #endif
>>
> I'm not sure about the original intent of the tests right now.
>
> Ramana
>

Thank you Ramana!

--Marat