[PATCH][LTO,ARM] Fix vector TYPE_MODE in streaming-out

[Christian Bruel]

On 12/16/2015 10:48 AM, Richard Biener wrote:
> On Tue, Dec 15, 2015 at 5:14 PM, Bernd Schmidt <bschmidt@redhat.com> wrote:
>> On 12/15/2015 04:09 PM, Christian Bruel wrote:
>>>
>>> in "normal" mode, the TYPE_MODE for vector_type __simd64_int8_t is set
>>> to V8QImode by arm_vector_mode_supported_p during the builtins type
>>> initializations, thanks to TARGET_NEON set bu the global flag.
>>>
>>> Now, in LTO mode the streamer writes the information for this
>>> vector_type as a scalar DImode, causing ICEs during arm_expand_builtin.
>>> The root cause of this is that the streamer-out uses TYPE_MODE in a
>>> context where the target_flags are not known return false for TARGET_NEON.
>>>
>>> The streamer-in then will then read the wrong mode that propagates to
>>> the back-end.
>>
>>
>>>   static void
>>>   pack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
>>>   {
>>> -  bp_pack_machine_mode (bp, TYPE_MODE (expr));
>>> +  bp_pack_machine_mode (bp, expr->type_common.mode);
>>
>>
>> This looks sensible given that tree-streamer-in uses SET_TYPE_MODE, which
>> just writes expr->type_common.mode.
>>
>> Make a new macro TYPE_MODE_RAW for this and I think the patch is ok
>> (although there's precedent for direct access in vector_type_mode, but I
>> think that's just bad).
>
> Yeah, though it's well-hidden ;)
>
> I think the patch is ok if you add a comment why we're not using TYPE_MODE here
> and if the patch passes the x86_64 vectorizer testsuite with -m32 -march=i586
> with no regressions (I do expect some FAILs with -march=i586 but the
> patch shouldn't
> regress anything).


Thanks,

no regressions for unix\{-m32/-march=i586,\}, arm and aarch64.

I'm about to commit the attached patch.

Christian

>
> Thanks,
> Richard.
>
>
>>
>> Bernd
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