Hi Richard,
Thanks for the reply.
> On 27 Aug 2024, at 7:05 pm, Richard Biener <richard.guent...@gmail.com> wrote:
>
> External email: Use caution opening links or attachments
>
>
> On Tue, Aug 27, 2024 at 8:23 AM Kugan Vivekanandarajah
> <kvivekana...@nvidia.com> wrote:
>>
>> Hi Richard,
>>
>>> On 22 Aug 2024, at 10:34 pm, Richard Biener <richard.guent...@gmail.com>
>>> wrote:
>>>
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> On Wed, Aug 21, 2024 at 12:08 PM Kugan Vivekanandarajah
>>> <kvivekana...@nvidia.com> wrote:
>>>>
>>>> Hi Richard,
>>>>
>>>>> On 20 Aug 2024, at 6:09 pm, Richard Biener <richard.guent...@gmail.com>
>>>>> wrote:
>>>>>
>>>>> External email: Use caution opening links or attachments
>>>>>
>>>>>
>>>>> On Fri, Aug 9, 2024 at 2:39 AM Kugan Vivekanandarajah
>>>>> <kvivekana...@nvidia.com> wrote:
>>>>>>
>>>>>> Thanks for the comments.
>>>>>>
>>>>>>> On 2 Aug 2024, at 8:36 pm, Richard Biener <richard.guent...@gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>> External email: Use caution opening links or attachments
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Aug 2, 2024 at 11:20 AM Kugan Vivekanandarajah
>>>>>>> <kvivekana...@nvidia.com> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> On 1 Aug 2024, at 10:46 pm, Richard Biener
>>>>>>>>> <richard.guent...@gmail.com> wrote:
>>>>>>>>>
>>>>>>>>> External email: Use caution opening links or attachments
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Thu, Aug 1, 2024 at 5:31 AM Kugan Vivekanandarajah
>>>>>>>>> <kvivekana...@nvidia.com> wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Mon, Jul 29, 2024 at 10:11 AM Andrew Pinski <pins...@gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> On Mon, Jul 29, 2024 at 12:57 AM Kugan Vivekanandarajah
>>>>>>>>>>> <kugan...@gmail.com> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> On Thu, Jul 25, 2024 at 10:19 PM Richard Biener
>>>>>>>>>>>> <richard.guent...@gmail.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Thu, Jul 25, 2024 at 4:42 AM Kugan Vivekanandarajah
>>>>>>>>>>>>> <kugan...@gmail.com> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 11:56 PM Richard Biener
>>>>>>>>>>>>>> <richard.guent...@gmail.com> wrote:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 10:27 AM Kugan Vivekanandarajah
>>>>>>>>>>>>>>> <kugan...@gmail.com> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Tue, Jul 23, 2024 at 10:35 AM Andrew Pinski
>>>>>>>>>>>>>>>> <pins...@gmail.com> wrote:
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> On Mon, Jul 22, 2024 at 5:26 PM Kugan Vivekanandarajah
>>>>>>>>>>>>>>>>> <kvivekana...@nvidia.com> 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.
>
>> 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 <kvivekana...@nvidia.com>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 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
>>>>>>>>>>>>>>>>>> <kvivekana...@nvidia.com>
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Bootstrapped and regression test on aarch64-linux-gnu. Is
>>>>>>>>>>>>>>>>>> this OK for trunk?
>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>> Kugan
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> ________________________________
>>>>>>>>>>>>>>>>>> From: Andrew Pinski <pins...@gmail.com>
>>>>>>>>>>>>>>>>>> Sent: Monday, 15 July 2024 5:30 AM
>>>>>>>>>>>>>>>>>> To: Kugan Vivekanandarajah <kvivekana...@nvidia.com>
>>>>>>>>>>>>>>>>>> Cc: gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org>;
>>>>>>>>>>>>>>>>>> richard.guent...@gmail.com <richard.guent...@gmail.com>
>>>>>>>>>>>>>>>>>> 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
>>>>>>>>>>>>>>>>>> <kvivekana...@nvidia.com> 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
>>>>>>>>>>>>>>>>>>> <kvivekana...@nvidia.com>
>>
>>
