Hi Andrew.
> On 28 Aug 2024, at 2:23 pm, Andrew Pinski <[email protected]> wrote:
>
> External email: Use caution opening links or attachments
>
>
> On Tue, Aug 27, 2024 at 8:54 PM Kugan Vivekanandarajah
> <[email protected]> wrote:
>>
>> Hi Richard,
>>
>> Thanks for the reply.
>>
>>> On 27 Aug 2024, at 7:05 pm, Richard Biener <[email protected]>
>>> wrote:
>>>
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> On Tue, Aug 27, 2024 at 8:23 AM Kugan Vivekanandarajah
>>> <[email protected]> wrote:
>>>>
>>>> Hi Richard,
>>>>
>>>>> On 22 Aug 2024, at 10:34 pm, Richard Biener <[email protected]>
>>>>> wrote:
>>>>>
>>>>> External email: Use caution opening links or attachments
>>>>>
>>>>>
>>>>> On Wed, Aug 21, 2024 at 12:08 PM Kugan Vivekanandarajah
>>>>> <[email protected]> wrote:
>>>>>>
>>>>>> Hi Richard,
>>>>>>
>>>>>>> On 20 Aug 2024, at 6:09 pm, Richard Biener <[email protected]>
>>>>>>> wrote:
>>>>>>>
>>>>>>> External email: Use caution opening links or attachments
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Aug 9, 2024 at 2:39 AM Kugan Vivekanandarajah
>>>>>>> <[email protected]> wrote:
>>>>>>>>
>>>>>>>> Thanks for the comments.
>>>>>>>>
>>>>>>>>> On 2 Aug 2024, at 8:36 pm, Richard Biener
>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>
>>>>>>>>> External email: Use caution opening links or attachments
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Fri, Aug 2, 2024 at 11:20 AM Kugan Vivekanandarajah
>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> On 1 Aug 2024, at 10:46 pm, Richard Biener
>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>
>>>>>>>>>>> External email: Use caution opening links or attachments
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Aug 1, 2024 at 5:31 AM Kugan Vivekanandarajah
>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> On Mon, Jul 29, 2024 at 10:11 AM Andrew Pinski <[email protected]>
>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Mon, Jul 29, 2024 at 12:57 AM Kugan Vivekanandarajah
>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Thu, Jul 25, 2024 at 10:19 PM Richard Biener
>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Thu, Jul 25, 2024 at 4:42 AM Kugan Vivekanandarajah
>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 11:56 PM Richard Biener
>>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 10:27 AM Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 10:35 AM Andrew Pinski
>>>>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> On Mon, Jul 22, 2024 at 5:26 PM Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> Revised based on the comment and moved it into existing
>>>>>>>>>>>>>>>>>>>> patterns as.
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> gcc/ChangeLog:
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> * match.pd: Extend A CMP 0 ? A : -A into (type)A CMP 0 ? A
>>>>>>>>>>>>>>>>>>>> : -A.
>>>>>>>>>>>>>>>>>>>> Extend A CMP 0 ? A : -A into (type) A CMP 0 ? A : -A.
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> gcc/testsuite/ChangeLog:
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> * gcc.dg/tree-ssa/absfloat16.c: New test.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> The testcase needs to make sure it runs only for targets
>>>>>>>>>>>>>>>>>>> that support
>>>>>>>>>>>>>>>>>>> float16 so like:
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> /* { dg-require-effective-target float16 } */
>>>>>>>>>>>>>>>>>>> /* { dg-add-options float16 } */
>>>>>>>>>>>>>>>>>> Added in the attached version.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> + /* (type)A >=/> 0 ? A : -A same as abs (A) */
>>>>>>>>>>>>>>>>> (for cmp (ge gt)
>>>>>>>>>>>>>>>>> (simplify
>>>>>>>>>>>>>>>>> - (cnd (cmp @0 zerop) @1 (negate @1))
>>>>>>>>>>>>>>>>> - (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
>>>>>>>>>>>>>>>>> - && !TYPE_UNSIGNED (TREE_TYPE(@0))
>>>>>>>>>>>>>>>>> - && bitwise_equal_p (@0, @1))
>>>>>>>>>>>>>>>>> + (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>>>>>>>>>>>>> + (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>>>>>>>>>>>>> + && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>>>>>>>>>>>>> + && ((VECTOR_TYPE_P (type)
>>>>>>>>>>>>>>>>> + && tree_nop_conversion_p (TREE_TYPE (@0),
>>>>>>>>>>>>>>>>> TREE_TYPE (@1)))
>>>>>>>>>>>>>>>>> + || (!VECTOR_TYPE_P (type)
>>>>>>>>>>>>>>>>> + && (TYPE_PRECISION (TREE_TYPE (@1))
>>>>>>>>>>>>>>>>> + <= TYPE_PRECISION (TREE_TYPE (@0)))))
>>>>>>>>>>>>>>>>> + && bitwise_equal_p (@1, @2))
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> I wonder about the bitwise_equal_p which tests @1 against @2
>>>>>>>>>>>>>>>>> now
>>>>>>>>>>>>>>>>> with the convert still applied to @1 - that looks odd. You
>>>>>>>>>>>>>>>>> are allowing
>>>>>>>>>>>>>>>>> sign-changing conversions but doesn't that change ge/gt
>>>>>>>>>>>>>>>>> behavior?
>>>>>>>>>>>>>>>>> Also why are sign/zero-extensions not OK for vector types?
>>>>>>>>>>>>>>>> Thanks for the review.
>>>>>>>>>>>>>>>> My main motivation here is for _Float16 as below.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> _Float16 absfloat16 (_Float16 x)
>>>>>>>>>>>>>>>> {
>>>>>>>>>>>>>>>> float _1;
>>>>>>>>>>>>>>>> _Float16 _2;
>>>>>>>>>>>>>>>> _Float16 _4;
>>>>>>>>>>>>>>>> <bb 2> [local count: 1073741824]:
>>>>>>>>>>>>>>>> _1 = (float) x_3(D);
>>>>>>>>>>>>>>>> if (_1 < 0.0)
>>>>>>>>>>>>>>>> goto <bb 3>; [41.00%]
>>>>>>>>>>>>>>>> else
>>>>>>>>>>>>>>>> goto <bb 4>; [59.00%]
>>>>>>>>>>>>>>>> <bb 3> [local count: 440234144]:\
>>>>>>>>>>>>>>>> _4 = -x_3(D);
>>>>>>>>>>>>>>>> <bb 4> [local count: 1073741824]:
>>>>>>>>>>>>>>>> # _2 = PHI <_4(3), x_3(D)(2)>
>>>>>>>>>>>>>>>> return _2;
>>>>>>>>>>>>>>>> }
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> This is why I added bitwise_equal_p test of @1 against @2 with
>>>>>>>>>>>>>>>> TYPE_PRECISION checks.
>>>>>>>>>>>>>>>> I agree that I will have to check for sign-changing
>>>>>>>>>>>>>>>> conversions.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Just to keep it simple, I disallowed vector types. I am not
>>>>>>>>>>>>>>>> sure if
>>>>>>>>>>>>>>>> this would hit vec types. I am happy to handle this if that is
>>>>>>>>>>>>>>>> needed.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I think with __builtin_convertvector you should be able to
>>>>>>>>>>>>>>> construct
>>>>>>>>>>>>>>> a testcase that does
>>>>>>>>>>>>>> Thanks.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> For the pattern,
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> /* A >=/> 0 ? A : -A same as abs (A) */
>>>>>>>>>>>>>> (for cmp (ge gt)
>>>>>>>>>>>>>> (simplify
>>>>>>>>>>>>>> (cnd (cmp @0 zerop) @1 (negate @1))
>>>>>>>>>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
>>>>>>>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE(@0))
>>>>>>>>>>>>>> && bitwise_equal_p (@0, @1))
>>>>>>>>>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>>>>>>>>>> (absu:type @0)
>>>>>>>>>>>>>> (abs @0)))))
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> the vector type doesn't seem right. For example, if we have a 4
>>>>>>>>>>>>>> element vector with some negative and positive, I don't think it
>>>>>>>>>>>>>> makes sense. Also, we dont seem to generate (cmp @0 zerop). Am I
>>>>>>>>>>>>>> missing it completely?
>>>>>>>>>>>>>
>>>>>>>>>>>>> Looks like I missed adding some vector testcases anyways here is
>>>>>>>>>>>>> one
>>>>>>>>>>>>> to get this, note it is C++ due to the C front-end not support
>>>>>>>>>>>>> `?:`
>>>>>>>>>>>>> for vectors yet (there is a patch).
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> #define vect8 __attribute__((vector_size(8)))
>>>>>>>>>>>>> vect8 int f(vect8 int a)
>>>>>>>>>>>>> {
>>>>>>>>>>>>> vect8 int na = -a;
>>>>>>>>>>>>> return (a > 0) ? a : na;
>>>>>>>>>>>>> }
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> At -O2 before forwprop1, we have:
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> vector(2) intD.9 a_2(D) = aD.2796;
>>>>>>>>>>>>> vector(2) intD.9 naD.2799;
>>>>>>>>>>>>> vector(2) <signed-boolean:32> _1;
>>>>>>>>>>>>> vector(2) intD.9 _4;
>>>>>>>>>>>>>
>>>>>>>>>>>>> na_3 = -a_2(D);
>>>>>>>>>>>>> _1 = a_2(D) > { 0, 0 };
>>>>>>>>>>>>> _4 = VEC_COND_EXPR <_1, a_2(D), na_3>;
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> And forwprop using match is able to do:
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> Applying pattern match.pd:6306, gimple-match-10.cc:19843
>>>>>>>>>>>>> gimple_simplified to _4 = ABS_EXPR <a_2(D)>;
>>>>>>>>>>>>> Removing dead stmt:_1 = a_2(D) > { 0, 0 };
>>>>>>>>>>>>> Removing dead stmt:na_3 = -a_2(D);
>>>>>>>>>>>>> ```
>>>>>>>>>>>>> (replace int with float and add -fno-signed-zeros you can get
>>>>>>>>>>>>> the ABS also).
>>>>>>>>>>>>>
>>>>>>>>>>>>> Note comparisons with vector types always generate a vector
>>>>>>>>>>>>> boolean
>>>>>>>>>>>>> type. So cond_expr will never show up with a vector comparison;
>>>>>>>>>>>>> only
>>>>>>>>>>>>> vec_cond.
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks for the information. I have revised the patch by adding
>>>>>>>>>>>> test case for the vector type. I will look at removing the
>>>>>>>>>>>> VEC_COND_EXPR as a follow up.
>>>>>>>>>>>
>>>>>>>>>>> This is likely a major task so do not get you distracted - I just
>>>>>>>>>>> mentioned it.
>>>>>>>>>>>
>>>>>>>>>>>> This is still rejected by the type checker.
>>>>>>>>>>>> v2hi absvect2 (v2hi x, int i) {
>>>>>>>>>>>> v2hi neg = -x;
>>>>>>>>>>>> v2si tmp = __builtin_convertvector (x, v2si);
>>>>>>>>>>>> return (tmp > 0) ? x : neg;
>>>>>>>>>>>> }
>>>>>>>>>>>> as:
>>>>>>>>>>>> error: incompatible vector types in conditional expression:
>>>>>>>>>>>> '__vector(2) int', 'v2hi' {aka '__vector(2) short int'} and 'v2hi'
>>>>>>>>>>>> {aka '__vector(2) short int'}
>>>>>>>>>>>> 8 | return (tmp > 0) ? x : neg;
>>>>>>>>>>>> | ~~~~~~~~~~^~~~~~~~~
>>>>>>>>>>>>
>>>>>>>>>>>> Also
>>>>>>>>>>>>
>>>>>>>>>>>> - (absu:type @0)
>>>>>>>>>>>> - (abs @0)))))
>>>>>>>>>>>> + (absu:type @1)
>>>>>>>>>>>> + (abs @1)))))
>>>>>>>>>>>>
>>>>>>>>>>>> Changing the @1 to @2 is resulting in failures. Existing tests
>>>>>>>>>>>> like the following would be optimized away in this case.
>>>>>>>>>>>> ```
>>>>>>>>>>>> unsigned abs_with_convert0 (int x)
>>>>>>>>>>>> {
>>>>>>>>>>>> unsigned int y = x;
>>>>>>>>>>>>
>>>>>>>>>>>> if (x < 0)
>>>>>>>>>>>> y = -y;
>>>>>>>>>>>>
>>>>>>>>>>>> return y;
>>>>>>>>>>>> }
>>>>>>>>>>>
>>>>>>>>>>> How so - the TYPE_UNSIGNED tests should make the pattern not
>>>>>>>>>>> trigger here?
>>>>>>>>>>>
>>>>>>>>>>>> ```
>>>>>>>>>>>> This follows the same intent as the original pattern.
>>>>>>>>>>>>
>>>>>>>>>>>> Bootstrapped and regression tested on aarch64-linux-gnu. Is this
>>>>>>>>>>>> OK for trunk.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> - (cnd (cmp @0 zerop) @1 (negate @1))
>>>>>>>>>>> - (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
>>>>>>>>>>> - && !TYPE_UNSIGNED (TREE_TYPE(@0))
>>>>>>>>>>> - && bitwise_equal_p (@0, @1))
>>>>>>>>>>> + (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>>>>>>> + (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>>>>>>> + && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>>>>>>> + && !TYPE_UNSIGNED (TREE_TYPE (@0))
>>>>>>>>>>>
>>>>>>>>>>> I think the outer type could be allowed signed if ...
>>>>>>>>>>>
>>>>>>>>>>> + && ((VECTOR_TYPE_P (TREE_TYPE (@0))
>>>>>>>>>>> + && VECTOR_TYPE_P (TREE_TYPE (@1))
>>>>>>>>>>> + && known_eq (TYPE_VECTOR_SUBPARTS (TREE_TYPE (@0)),
>>>>>>>>>>> + TYPE_VECTOR_SUBPARTS (TREE_TYPE (@1)))
>>>>>>>>>>>
>>>>>>>>>>> this is always true
>>>>>>>>>>>
>>>>>>>>>>> + && element_precision (TREE_TYPE (@1))
>>>>>>>>>>> + <= element_precision (TREE_TYPE (@0)))
>>>>>>>>>>> + || (!VECTOR_TYPE_P (TREE_TYPE (@0))
>>>>>>>>>>> + && (TYPE_PRECISION (TREE_TYPE (@1))
>>>>>>>>>>> + <= TYPE_PRECISION (TREE_TYPE (@0)))))
>>>>>>>>>>>
>>>>>>>>>>> ... you make the precision strictly larger. With both unsigned the
>>>>>>>>>>> same
>>>>>>>>>>> precision case should have been stripped anyway.
>>>>>>>>>>>
>>>>>>>>>>> You can use element_precision for both vector and non-vector so I
>>>>>>>>>>> think this
>>>>>>>>>>> should simplify to just checking element_precision.
>>>>>>>>>>>
>>>>>>>>>>> + (absu:type @1)
>>>>>>>>>>> + (abs @1)))))
>>>>>>>>>>>
>>>>>>>>>>> I still think this needs to be @2 for type correctness. @1 is only
>>>>>>>>>>> bitwise equal,
>>>>>>>>>>> it could have different sign. I think we should drop
>>>>>>>>>>> bitwise_equal_p with the
>>>>>>>>>>> convert now in and instead have a matching constraint.
>>>>>>>>>>
>>>>>>>>>> Thanks, so this should translate to:
>>>>>>>>>>
>>>>>>>>>> /* (type)A >=/> 0 ? A : -A same as abs (A) */
>>>>>>>>>> (for cmp (ge gt)
>>>>>>>>>> (simplify
>>>>>>>>>> (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>>>>>
>>>>>>>>> Oh, I mis-read this as unsigned, so this makes the conversions
>>>>>>>>> to always sign-extend which means it's important to ensure
>>>>>>>>> the type of @0 is also signed.
>>>>>>>>>
>>>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@2))
>>>>>>>>>> && ((element_precision (TREE_TYPE (@1))
>>>>>>>>>> < element_precision (TREE_TYPE (@0))
>>>>>>>>>> || operand_equal_p (@1, @0)))
>>>>>>>>>
>>>>>>>>> which means <= might be better then.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> && bitwise_equal_p (@1, @2))
>>>>>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>>>>>> (absu:type @2)
>>>>>>>>>> (abs @2)))))
>>>>>>>>>>
>>>>>>>>>> However with this, I am seeing: Note that the @2 for these are
>>>>>>>>>> unsigned.
>>>>>>>>>
>>>>>>>>> I see, so we rely on @1 being the signed equivalent of @2 which might
>>>>>>>>> or
>>>>>>>>> might not be signed. I guess that indeed we want @2 here.
>>>>>>>> Sorry I am not sure I understand this. When @2 is unsigned, ABS_EXPR
>>>>>>>> and ABSU_EXPR is not
>>>>>>>> For example:
>>>>>>>> With
>>>>>>>> /* (type)A >=/> 0 ? A : -A same as abs (A) */
>>>>>>>> (for cmp (ge gt)
>>>>>>>> (simplify
>>>>>>>> (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@0))
>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>>>> && element_precision (TREE_TYPE (@1))
>>>>>>>> <= element_precision (TREE_TYPE (@0))
>>>>>>>> && bitwise_equal_p (@1, @2))
>>>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>>>> (absu:type @2)
>>>>>>>> (abs @2)))))
>>>>>>>>
>>>>>>>> The test case below becomes:
>>>>>>>>
>>>>>>>> unsigned abs_with_convert0 (int x)
>>>>>>>> {
>>>>>>>> unsigned int y = x;
>>>>>>>>
>>>>>>>> if (x < 0)
>>>>>>>> y = -y;
>>>>>>>>
>>>>>>>> return y;
>>>>>>>> }
>>>>>>>>
>>>>>>>> unsigned int abs_with_convert0 (int x)
>>>>>>>> {
>>>>>>>> unsigned int y;
>>>>>>>>
>>>>>>>> <bb 2> :
>>>>>>>> y_3 = (unsigned int) x_2(D);
>>>>>>>> if (x_2(D) < 0)
>>>>>>>> goto <bb 3>; [INV]
>>>>>>>> else
>>>>>>>> goto <bb 4>; [INV]
>>>>>>>>
>>>>>>>> <bb 3> :
>>>>>>>> y_4 = -y_3;
>>>>>>>>
>>>>>>>> <bb 4> :
>>>>>>>> # y_1 = PHI <y_3(2), y_4(3)>
>>>>>>>> return y_1;
>>>>>>>>
>>>>>>>> }
>>>>>>>>
>>>>>>>> To:
>>>>>>>>
>>>>>>>>
>>>>>>>> unsigned int abs_with_convert0 (int x)
>>>>>>>> {
>>>>>>>> unsigned int y;
>>>>>>>> unsigned int _5;
>>>>>>>>
>>>>>>>> <bb 2> :
>>>>>>>> y_3 = (unsigned int) x_2(D);
>>>>>>>> _5 = ABSU_EXPR <y_3>;
>>>>>>>> return _5;
>>>>>>>>
>>>>>>>> }
>>>>>>>>
>>>>>>>> This is an invalid gimple. Are you suggesting that we should also
>>>>>>>> check if @2 is not UNSIGNED? If that is what you want, couple of test
>>>>>>>> cases in the test suite including phi-opt-37.c would fail.
>>>>>>>
>>>>>>> Trying to swap in the discussion after vacation ... iff @2 might be
>>>>>>> unsigned then you'd need
>>>>>>> a conversion to signed to make 'abs' make sense.
>>>>>>>
>>>>>>>> (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@0))
>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>>>
>>>>>>> so this doesn't put any constraints on the signedness of @2
>>>>>>>
>>>>>>> What kind of extensions are valid on @1? I think this warrants a
>>>>>>> comment. I think in the end the compare should be signed to
>>>>>>> fit 'abs' semantics, but a zero-extension (unsigned @1) should be
>>>>>>> OK? So why constrain the sign of @1?
>>>>>> I thing it is the conversion to signed (sign extend) that we want to
>>>>>> support, But for cases like:
>>>>>> signed abs_with_convert1 (unsigned x)
>>>>>> {
>>>>>> int y = x;
>>>>>>
>>>>>> if (y < 0)
>>>>>> y = -x;
>>>>>>
>>>>>> return y;
>>>>>> }
>>>>>> @2 is unsigned.
>>>>>>
>>>>>>>> && element_precision (TREE_TYPE (@1))
>>>>>>>> <= element_precision (TREE_TYPE (@0))
>>>>>>>> && bitwise_equal_p (@1, @2))
>>>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>>>> (absu:type @2)
>>>>>>>> (abs @2)))))
>>>>>>>
>>>>>>> Of course then you'd want to convert @2 to signed?
>>>>>>
>>>>>> We have some test cases where @2 is unsigned where original pattern
>>>>>> triggers and will not with the new pattern. For example
>>>>>> gcc.dg/tree-ssa/phi-opt-37.c.
>>>>>>
>>>>>> Should we create a new pattern as:
>>>>>> /* (type)A >=/> 0 ? A : -A same as abs (A) */
>>>>>> (for cmp (ge gt)
>>>>>> (simplify
>>>>>> (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>>>>> && !TYPE_UNSIGNED (TREE_TYPE (@2))
>>>>>> && element_precision (TREE_TYPE (@1))
>>>>>> <= element_precision (TREE_TYPE (@0))
>>>>>> && bitwise_equal_p (@1, @2))
>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>> (abs @2)
>>>>>> (abs @2)))))
>>>>>>
>>>>>> And leave the old pattern as it is? Otherwise if we decide to use @2, we
>>>>>> have to XFAIL these cases unless I am missing spmething.
>>>>>
>>>>> No, I think we want a single pattern. I meant you possibly need to do
>>>>>
>>>>> (with
>>>>> { tree stype = signed_type_for (TREE_TYPE (@2)); }
>>>>> (if (TYPE_UNSIGNED (type))
>>>>> (absu (convert:stype @2))
>>>>> (abs (convert:stype @2))))
>>>>>
>>>>> for when @2 is unsigned?
>>>>
>>>> Thanks. I have changed accordingly.
>>>>
>>>> I have also changed gcc.dg/tree-ssa/phi-opt-37.c to check phiopt2 as in
>>>> phiopt1 we don’t now match because of:
>>>> phiopt match-simplify back:
>>>> _5 = (signed int) x_2(D);
>>>> _7 = ABSU_EXPR <_5>;
>>>> result: _7
>>>> rejected because early
>>>
>>> ? I don't understand what you are saying.
>>
>> This is the dump from phiopt. Even though it is matching,
>> /* Return TRUE if SEQ/OP pair should be allowed during early phiopt.
>> Currently this is to allow MIN/MAX and ABS/NEGATE and constants. */
>> static bool
>> phiopt_early_allow (gimple_seq &seq, gimple_match_op &op) is rejecting it,
>> as the dump shows.
>
> So I looked into this slightly. I think the match patterns are greedy
> when it comes to optional converts, in that match tries to match with
> convert first and for integer types but bitwise_equal_p will handle a
> nop_convert here.
> So for scalar integer types, maybe skip `TYPE_PRECISION (TREE_TYPE
> (@1)) == TYPE_PRECISION (TREE_TYPE (@0))` as that is handled via
> bitwise_equal_p call and we don't want an extra convert being added by
> the simplification
phiopt_early_allow only allow single instruction sequences. But since we now
use @2 instead of @1, we will need the conversion. Sorry I don’t understand the
fix you want.
Thanks,
Kugan
> since it is already there as we might not recover
> an usage of that until much later. An example is if the ssa name of
> the convert is used twice and we now have 2 ssa names with the same
> convert.
>
> Thanks,
> Andrew Pinski
>
>
>>
>>>
>>>> Bootstrapped and regression tested on aarch64-linux-gnu. Is this OK?
>>>
>>> In both cases you do
>>>
>>> - (cnd (cmp @0 zerop) @1 (negate @1))
>>> - (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
>>> - && !TYPE_UNSIGNED (TREE_TYPE(@0))
>>> ...
>>> + (cnd (cmp (convert?@0 @1) zerop) @2 (negate @2))
>>> + (if (!HONOR_SIGNED_ZEROS (TREE_TYPE (@1))
>>> + /* Support SEXT of @0 only. */
>>> + && !TYPE_UNSIGNED (TREE_TYPE (@1))
>>> + && element_precision (TREE_TYPE (@1))
>>> + <= element_precision (TREE_TYPE (@0))
>>>
>>> where formerly we require a signed comparison, a check that you drop
>>> and one that IMO is important (I would guess for unsigned we never
>>> match the pattern as compares against zero are simplified to eq/ne,
>>> but still). I think that
>>
>> From what I understand, we allow a signed comparison even now.
>> We don’t allow unsigned comparison agains zero as earlier. We allow
>> conversion of unsigned type to signed type before comparing. Am I missing
>> something?
>>
>>>
>>> unsigned a;
>>> (int)a < 0 : -a : a
>>
>>>
>>> is valid to be matched to ABSU but is excluded by the requirement
>>> of a sign-extension.
>>
>> This is currently handled as :
>> unsigned int abs1 (unsigned int x)
>> {
>> signed int _6;
>> unsigned int _7;
>>
>> <bb 2> [local count: 1073741824]:
>> _6 = (signed int) x_3(D);
>> _7 = ABSU_EXPR <_6>;
>> return _7;
>>
>> }
>>
>>>
>>> unsigned a;
>>> (long)a < 0 : -a : a
>>>
>>> isn't a ABSU though. That means
>>
>> Yes, this gets folded in .015.cfg as:
>>
>> Removing basic block 3
>> Merging blocks 2 and 4
>> Merging blocks 2 and 5
>> ;; 1 loops found
>> ;;
>> ;; Loop 0
>> ;; header 0, latch 1
>> ;; depth 0, outer -1
>> ;; nodes: 0 1 2
>> ;; 2 succs { 1 }
>> unsigned int abs2 (unsigned int x)
>> {
>> unsigned int D.4427;
>>
>> <bb 2> :
>> D.4427 = x;
>> // predicted unlikely by early return (on trees) predictor.
>> return D.4427;
>>
>> }
>>
>>
>> Thanks,
>> Kugan
>>>
>>> /* Support sign-change or SEXT of @0 only. */
>>> && (element_precision (TREE_TYPE (@1)) == element_precision (TREE_TYPE (@0))
>>> || (!TYPE_UNSIGNED (...)
>>> && ...))
>>>
>>> would be better. That might also solve your problem with phi-opt-37.c?
>>>
>>> Richard.
>>>
>>>
>>>> Thanks,
>>>> Kugan
>>>>
>>>>
>>>>
>>>>>
>>>>> Richard.
>>>>>
>>>>>
>>>>>> Thanks,
>>>>>> Kugan
>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Kugan
>>>>>>>>
>>>>>>>>>
>>>>>>>>>> Tests that now fail, but worked before (4 tests):
>>>>>>>>>>
>>>>>>>>>> gcc: gcc.dg/tree-ssa/phi-opt-36.c scan-tree-dump-not phiopt2 "if "
>>>>>>>>>> gcc: gcc.dg/tree-ssa/phi-opt-36.c scan-tree-dump-times phiopt1 "if "
>>>>>>>>>> 2
>>>>>>>>>> gcc: gcc.dg/tree-ssa/phi-opt-37.c scan-tree-dump-not phiopt1 "if
>>>>>>>>>> "gcc: gcc.dg/tree-ssa/phi-opt-37.c scan-tree-dump-times phiopt1
>>>>>>>>>> "ABSU_EXPR <" 2
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> unsigned f2(int A)
>>>>>>>>>> {
>>>>>>>>>> unsigned t = A;
>>>>>>>>>> // A >= 0? A : -A same as abs (A)
>>>>>>>>>> if (A >= 0) return t;
>>>>>>>>>> return -t;
>>>>>>>>>> }
>>>>>>>>>>
>>>>>>>>>> unsigned abs_with_convert0 (int x)
>>>>>>>>>> {
>>>>>>>>>> unsigned int y = x;
>>>>>>>>>>
>>>>>>>>>> if (x < 0)
>>>>>>>>>> y = -y;
>>>>>>>>>>
>>>>>>>>>> return y;
>>>>>>>>>> }
>>>>>>>>>> unsigned abs_with_convert1 (unsigned x)
>>>>>>>>>> {
>>>>>>>>>> int y = x;
>>>>>>>>>>
>>>>>>>>>> if (y < 0)
>>>>>>>>>> x = -x;
>>>>>>>>>>
>>>>>>>>>> return x;
>>>>>>>>>> }
>>>>>>>>>>
>>>>>>>>>> In the original pattern, we have check for !TYPE_UNSIGNED
>>>>>>>>>> (TREE_TYPE(@0)) and (absu:type @0)
>>>>>>>>>>
>>>>>>>>>> Shouldnt that translate !TYPE_UNSIGNED (TREE_TYPE(@1)) and
>>>>>>>>>> (absu:type @1) in the new pattern
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Kugan
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Same comments apply to the 2nd pattern update.
>>>>>>>>>>>
>>>>>>>>>>> Richard.
>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Kugan
>>>>>>>>>>>>
>>>>>>>>>>>> gcc/ChangeLog:
>>>>>>>>>>>>
>>>>>>>>>>>> * match.pd: Extend A CMP 0 ? A : -A into (type)A CMP 0 ? A : -A.
>>>>>>>>>>>> Extend A CMP 0 ? A : -A into (type) A CMP 0 ? A : -A.
>>>>>>>>>>>>
>>>>>>>>>>>> gcc/testsuite/ChangeLog:
>>>>>>>>>>>>
>>>>>>>>>>>> * g++.dg/absvect.C: New test.
>>>>>>>>>>>> * gcc.dg/tree-ssa/absfloat16.c: New test.
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> signed-off-by: Kugan Vivekanandarajah <[email protected]>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Note I think we should be able to merge VEC_COND_EXPR and COND_EXPR
>>>>>>>>>>>> codes by instead looking whether the condition is vector or
>>>>>>>>>>>> scalar. Fallout
>>>>>>>>>>>> might be a bit too big, but it might be a thing to try.
>>>>>>>>>>>>
>>>>>>>>>>>> Richard.
>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>> Andrew Pinski
>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>> Kugan
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> + (absu:type @1)
>>>>>>>>>>>>>>>>> + (abs @1)))))
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> I think this should use @2 now.
>>>>>>>>>>>>>>>> I will change this.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>> Kugan
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Thanks.
>>>>>>>>>>>>>>>>>> Kugan
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> (like what is in gcc.dg/c11-floatn-3.c and others).
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Other than that it looks good but I can't approve it.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>> Andrew Pinski
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> Signed-off-by: Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>>>>> <[email protected]>
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> Bootstrapped and regression test on aarch64-linux-gnu. Is
>>>>>>>>>>>>>>>>>>>> this OK for trunk?
>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>>> Kugan
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> ________________________________
>>>>>>>>>>>>>>>>>>>> From: Andrew Pinski <[email protected]>
>>>>>>>>>>>>>>>>>>>> Sent: Monday, 15 July 2024 5:30 AM
>>>>>>>>>>>>>>>>>>>> To: Kugan Vivekanandarajah <[email protected]>
>>>>>>>>>>>>>>>>>>>> Cc: [email protected] <[email protected]>;
>>>>>>>>>>>>>>>>>>>> [email protected] <[email protected]>
>>>>>>>>>>>>>>>>>>>> Subject: Re: [PATCH] MATCH: add abs support for half float
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> External email: Use caution opening links or attachments
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> On Sun, Jul 14, 2024 at 1:12 AM Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>>>>> <[email protected]> wrote:
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> This patch extends abs detection in matched for half
>>>>>>>>>>>>>>>>>>>>> float.
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> Bootstrapped and regression test on aarch64-linux-gnu. Is
>>>>>>>>>>>>>>>>>>>>> this OK for trunk?
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> This is basically this pattern:
>>>>>>>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>>>>>>>> /* A >=/> 0 ? A : -A same as abs (A) */
>>>>>>>>>>>>>>>>>>>> (for cmp (ge gt)
>>>>>>>>>>>>>>>>>>>> (simplify
>>>>>>>>>>>>>>>>>>>> (cnd (cmp @0 zerop) @1 (negate @1))
>>>>>>>>>>>>>>>>>>>> (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
>>>>>>>>>>>>>>>>>>>> && !TYPE_UNSIGNED (TREE_TYPE(@0))
>>>>>>>>>>>>>>>>>>>> && bitwise_equal_p (@0, @1))
>>>>>>>>>>>>>>>>>>>> (if (TYPE_UNSIGNED (type))
>>>>>>>>>>>>>>>>>>>> (absu:type @0)
>>>>>>>>>>>>>>>>>>>> (abs @0)))))
>>>>>>>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> except extended to handle an optional convert. Why didn't
>>>>>>>>>>>>>>>>>>>> you just
>>>>>>>>>>>>>>>>>>>> extend the above pattern to handle the convert instead?
>>>>>>>>>>>>>>>>>>>> Also I think
>>>>>>>>>>>>>>>>>>>> you have an issue with unsigned types with the comparison.
>>>>>>>>>>>>>>>>>>>> Also you should extend the -abs(A) pattern right below it
>>>>>>>>>>>>>>>>>>>> in a similar fashion.
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>>> Andrew Pinski
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> gcc/ChangeLog:
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> * match.pd: Add pattern to convert (type)A >=/> 0 ? A :
>>>>>>>>>>>>>>>>>>>>> -A into abs (A) for half float.
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> gcc/testsuite/ChangeLog:
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> * gcc.dg/tree-ssa/absfloat16.c: New test.
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> Signed-off-by: Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>>>>>> <[email protected]>
