[PATCH] Build proper false constant for VECTOR_TYPEs.

[Martin Liška]

On 9/9/19 8:53 PM, Jeff Law wrote:
> On 9/6/19 7:36 AM, Martin Liška wrote:
>> Hi.
>>
>> I've been working on transition of cond expressions to match.pd.
>> With my changes I noticed there's one wrong pattern that leads to:
>>
>> Transforming _6 > _7 & _6 < _7 into 0
>> ...
>> /home/marxin/Programming/gcc/gcc/testsuite/c-c++-common/vector-compare-3.c:20:1: error: the first argument of a ‘vec_cond_expr’ must be of a boolean vector type of the same number of elements as the result
>>     20 | g (v4i *x, v4i const *y, v4i *z, v4i *t)
>>        | ^
>> vector(4) int
>> _Bool
>> _9 = VEC_COND_EXPR <0, { -1, -1, -1, -1 }, { 0, 0, 0, 0 }>;
>>
>> which is wrong.
>>
>> Proper simlification is:
>> Transforming _6 > _7 & _6 < _7 into { 0, 0, 0, 0 }
>>
>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>>
>> Ready to be installed?
>> Thanks,
>> Martin
>>
>> gcc/ChangeLog:
>>
>> 2019-09-06  Martin Liska  <mliska@suse.cz>
>>
>> 	* match.pd: For vector types, take type from a vector argument
>> 	of the expression.
> Seems like you're going to have an overly long time in match.pd.

We'll see ;)

> Perhaps store the desired type into a local or split the line.

As Marc pointed out the patch is incorrect. I'm working on the proper
fix.

Martin

> 
> OK with that change.
> 
> jeff
>