On 9/5/19 3:17 PM, Richard Biener wrote:
> On Tue, 16 Jul 2019, Li Jia He wrote:
> 
>> Hi,
>>
>>   I made some changes based on the recommendations. Would you like to
>>   help me to see it again ? Sorry, it took so long time to provide the
>>   patch.
>>
>>   Note: 1. I keep the code for and_comparisons_1 and or_comparisons_1.
>> 	The reason is that I did not found a good way to handle the
>> 	optimization of '((x CODE1 y) AND (x CODE2 y))' in match.pd.
>> 	Maybe I missing some important information about match.pd.
>> 	2. The gimple_resimplify2 function is not used.  Since stmt1,
>> 	stmt2, lhs1 and lhs2 are allocated on the stack, Is there a
>> 	question with the value on the stack as the return value ?
>> 	I may have misunderstood Richard's intention.
> 
> And now for the match.pd patch.
> 
> +/* x >  y  &&  x != XXX_MIN  -->  x > y  */
> +(for and (truth_and bit_and)
> + (simplify
> +  (and:c (gt:c@3 @0 @1) (ne @0 INTEGER_CST@2))
> +  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) && INTEGRAL_TYPE_P 
> (TREE_TYPE(@1))
> +       && (wi::eq_p (wi::to_wide (@2), wi::min_value (TREE_TYPE (@2)))))
> +    @3)))
> +
> +/* x >  y  &&  x == XXX_MIN  -->  false  */
> +(for and (truth_and bit_and)
> + (simplify
> +  (and:c (gt:c @0 @1) (eq @0 INTEGER_CST@2))
> +  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) && INTEGRAL_TYPE_P 
> (TREE_TYPE(@1))
> +       && (wi::eq_p (wi::to_wide (@2), wi::min_value (TREE_TYPE (@2)))))
> +    { boolean_false_node; })))
> 
> you could merge those two via
> 
>  (for eqne (eq ne)
>   (for and (....
>    (simplify
>     (and:c (gt:c @0 @1) (eqne @0 INTEGER_CST@2))
>     (if (...)
>      (switch
>       (if (eqne == NE_EXPR)
>        @3)
>       (if (eqne == EQ_EXPR)
>        { constant_boolean_node (false, type); }))))
> 
> notice using constant_boolean_node (false, type); instead of
> boolean_false_node.  I suspect more unification is possible.
> 
> Also you could do
> 
> (match min_value
>  INTEGER_CST
>  (if (INTEGRAL_TYPE_P (type)
>       && wi::eq_p (wi::to_wide (t), wi::min_value (type)))))
> 
> and then write
> 
>  (simplify
>   (and:c (gt:c @0 @1) (eq @0 min_value))
>   (...
> 
> Your
> 
> (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) && INTEGRAL_TYPE_P
> (TREE_TYPE(@1))
> 
> is redundant, it's enough to check either @0 or @1 given they
> have to be compatible for the gt operation.  Note you probably
> want to use
> 
>   (and:c (gt:c @0 @1) (eq @@0 min_value))
> 
> and verify that types_match (@1, @0) because when @0 are a constant
> (and (eq @0 min_value) is not folded which can happen) then they
> might have different types and thus you could have
> (SHORT_MAX > intvar) && (SHORT_MAX == SHORT_MAX)
> 
> That said, the patterns can be quite a bit simplified I think.
> 
> Richard.
> 

Likewise, I applied the suggested simplification.

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin