[PR66726] Factor conversion out of COND_EXPR

[Jeff Law]

On 07/15/2015 11:52 PM, Kugan wrote:
>
>>>
>>> diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
>>> index 932c83a..3058eb5 100644
>>> --- a/gcc/tree-ssa-reassoc.c
>>> +++ b/gcc/tree-ssa-reassoc.c
>>
>>>        return false;
>>>      bb = gimple_bb (stmt);
>>>      if (!single_succ_p (bb))
>>> @@ -2729,9 +2743,8 @@ final_range_test_p (gimple stmt)
>>>
>>>      lhs = gimple_assign_lhs (stmt);
>>>      rhs = gimple_assign_rhs1 (stmt);
>>> -  if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
>>> -      || TREE_CODE (rhs) != SSA_NAME
>>> -      || TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE)
>>> +  if (TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE
>>> +      && TREE_CODE (TREE_TYPE (lhs)) != BOOLEAN_TYPE)
>>>        return false;
>> So you're ensuring that one of the two is a boolean...  Note that
>> previously we ensured that the rhs was a boolean and the lhs was an
>> integral type (which I believe is true for booleans).
>>
>> Thus if we had
>> bool x;
>> int y;
>>
>> x = (bool) y;
>>
>> The old code would have rejected that case.  But I think it gets through
>> now, right?
>>
>> I think once that issue is addressed, this will be good for the trunk.
>>
>
> Thanks for the review. How about:
>
> -  if (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
> -      || TREE_CODE (rhs) != SSA_NAME
> -      || TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE)
> +  if (gimple_assign_cast_p (stmt)
> +      && (!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
> +	  || TREE_CODE (rhs) != SSA_NAME
> +	  || TREE_CODE (TREE_TYPE (rhs)) != BOOLEAN_TYPE))
But then I think you need to verify that for the  _234 = a_2(D) == 2; 
case that type of the RHS is a boolean.

ie, each case has requirements for the types.  I don't think they can be 
reasonably unified.  So something like this:

if (gimple_assign_cast_p (stmt)
     && ! (correct types for cast)
    return false;

if (!gimple_assign_cast_p (stmt)
     && ! (correct types for tcc_comparison case))
   return false;


This works because we've already verified that it's either a type 
conversion or a comparison on the RHS.

Jeff