On Mon, Apr 8, 2013 at 3:27 PM, Jeff Law <l...@redhat.com> wrote:
> On 04/08/2013 03:45 AM, Richard Biener wrote:
>
>>> @@ -8584,6 +8584,43 @@ simplify_cond_using_ranges (gimple stmt)
>>> }
>>> }
>>>
>>> + /* If we have a comparison of a SSA_NAME boolean against
>>> + a constant (which obviously must be [0..1]). See if the
>>> + SSA_NAME was set by a type conversion where the source
>>> + of the conversion is another SSA_NAME with a range [0..1].
>>> +
>>> + If so, we can replace the SSA_NAME in the comparison with
>>> + the RHS of the conversion. This will often make the type
>>> + conversion dead code which DCE will clean up. */
>>> + if (TREE_CODE (op0) == SSA_NAME
>>> + && TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE
>>
>>
>> Use
>>
>> (TREE_CODE (TREE_TYPE (op0)) == BOOLEAN_TYPE
>> || (INTEGRAL_TYPE_P (TREE_TYPE (op0))
>> && TYPE_PRECISION (TREE_TYPE (op0)) == 1))
>>
>> to catch some more cases.
>
> Good catch. Done.
>
>
>>
>>> + && is_gimple_min_invariant (op1))
>>
>>
>> In this case it's simpler to test TREE_CODE (op1) == INTEGER_CST.
>
> Agreed & fixed.
>
>
>>
>>> + {
>>> + gimple def_stmt = SSA_NAME_DEF_STMT (op0);
>>> + tree innerop;
>>> +
>>> + if (!is_gimple_assign (def_stmt)
>>> + || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
>>> + return false;
>>> +
>>> + innerop = gimple_assign_rhs1 (def_stmt);
>>> +
>>> + if (!SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop))
>>
>>
>> As Steven said, the abnormal check is not necessary, but for completeness
>> you should check TREE_CODE (innerop) == SSA_NAME. Valid (but
>> unfolded) GIMPLE can have (_Bool) 1, too.
>
> Agreed & fixed.
>
>
>>
>> Note that we already have code with similar functionality (see if a
>> conversion would alter the value of X) as part of optimizing
>> (T1)(T2)X to (T1)X in simplify_conversion_using_ranges. Maybe
>> a part of it can be split out and used to simplify conditions for
>> a bigger range of types than just compares against boolean 0/1.
>
> That may be a follow-up -- there's still several of these things I'm looking
> at. I wanted to go ahead and start pushing out those which were clearly
> improvements rather than queue them while I looked at all the oddities I'm
> seeing in the dumps.
Fine with me.
Richard.
> jeff
>
