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Re: [PR70920] transform (intptr_t) x eq/ne CST to x eq/ne (typeof x) cst


On 25 July 2016 at 14:32, Richard Biener <rguenther@suse.de> wrote:
> On Mon, 25 Jul 2016, Prathamesh Kulkarni wrote:
>
>> Hi Richard,
>> The attached patch tries to fix PR70920.
>> It adds your pattern from comment 1 in the PR
>> (with additional gating on INTEGRAL_TYPE_P to avoid regressing finalize_18.f90)
>> and second pattern, which is reverse of the first transform.
>> I needed to update ssa-dom-branch-1.c because with patch applied,
>> jump threading removed the second if (i != 0B) block.
>> The dumps with and without patch for ssa-dom-branch-1.c start
>> to differ with forwprop1:
>>
>> before:
>>  <bb 3>:
>>   _1 = temp_16(D)->code;
>>   _2 = _1 == 42;
>>   _3 = (int) _2;
>>   _4 = (long int) _3;
>>   temp_17 = (struct rtx_def *) _4;
>>   if (temp_17 != 0B)
>>     goto <bb 4>;
>>   else
>>     goto <bb 8>;
>>
>> after:
>> <bb 3>:
>>   _1 = temp_16(D)->code;
>>   _2 = _1 == 42;
>>   _3 = (int) _2;
>>   _4 = (long int) _2;
>>   temp_17 = (struct rtx_def *) _4;
>>   if (_1 == 42)
>>     goto <bb 4>;
>>   else
>>     goto <bb 8>;
>>
>> I suppose the transform is correct for above test-case ?
>>
>> Then vrp dump shows:
>>  Threaded jump 5 --> 9 to 13
>>   Threaded jump 8 --> 9 to 13
>>   Threaded jump 3 --> 9 to 13
>>   Threaded jump 12 --> 9 to 14
>> Removing basic block 9
>> basic block 9, loop depth 0
>>  pred:
>> if (i1_10(D) != 0B)
>>   goto <bb 10>;
>> else
>>   goto <bb 11>;
>>  succ:       10
>>              11
>>
>> So there remained two instances of if (i1_10 (D) != 0B) in dom2 dump file,
>> and hence needed to update the test-case.
>>
>> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>> OK to commit ?
>
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3408,3 +3408,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>          { CONSTRUCTOR_ELT (ctor, idx / k)->value; })
>         (BIT_FIELD_REF { CONSTRUCTOR_ELT (ctor, idx / k)->value; }
>                        @1 { bitsize_int ((idx % k) * width); })))))))))
> +
> +/* PR70920: Transform (intptr_t)x eq/ne CST to x eq/ne (typeof x) CST.
> */
> +
> +(for cmp (ne eq)
> + (simplify
> +  (cmp (convert@2 @0) INTEGER_CST@1)
> +  (if (POINTER_TYPE_P (TREE_TYPE (@0))
> +       && INTEGRAL_TYPE_P (TREE_TYPE (@2)))
>
> you can use @1 here and omit @2.
>
> +   (cmp @0 (convert @1)))))
> +
> +/* Reverse of the above case:
> +   x has integral_type, CST is a pointer constant.
> +   Transform (typeof CST)x eq/ne CST to x eq/ne (typeof x) CST.  */
> +
> +(for cmp (ne eq)
> + (simplify
> +  (cmp (convert @0) @1)
> +  (if (POINTER_TYPE_P (TREE_TYPE (@1))
> +       && INTEGRAL_TYPE_P (TREE_TYPE (@0)))
> +    (cmp @0 (convert @1)))))
>
> The second pattern lacks the INTEGER_CST on @1 so it doesn't match
> its comment.  Please do not add vertical space between pattern
> comment and pattern.
>
> Please place patterns not at the end of match.pd but where similar
> transforms are done.  Like after
>
> /* Simplify pointer equality compares using PTA.  */
> (for neeq (ne eq)
>  (simplify
>   (neeq @0 @1)
>   (if (POINTER_TYPE_P (TREE_TYPE (@0))
>        && ptrs_compare_unequal (@0, @1))
>    { neeq == EQ_EXPR ? boolean_false_node : boolean_true_node; })))
>
> please also share the (for ...) for both patterns or merge them
> by changing the condition to
>
>   (if ((POINTER_TYPE_P (TREE_TYPE (@0))
>         && INTEGRAL_TYPE_P (TREE_TYPE (@1)))
>        || (INTEGRAL_TYPE_P (TREE_TYPE (@0))
>            && POINTER_TYPE_P (TREE_TYPE (@1))))
>
Hi,
Done suggested changes in this version.
pr70920-4.c (test-case in patch) is now folded during  ccp instead of
forwprop after merging the
two patterns.
Passes bootstrap+test on x86_64-unknown-linux-gnu.
OK for trunk ?

Thanks,
Prathamesh
> Richard.
>
>> PS: Writing changelog entries for match.pd is a bit tedious.
>> Should we add optional names for pattern so we can refer to them by names
>> in the ChangeLog for the more complicated ones ?
>> Or maybe just use comments:
>> (simplify /* name */ ... ) -;)
>
> That will add the fun of inventing names ;)
>
>> Thanks,
>> Prathamesh
>>
>
> --
> Richard Biener <rguenther@suse.de>
> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)

Attachment: patch-2.diff
Description: Text document

Attachment: ChangeLog
Description: Binary data


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