Re: Add simple sign-stripping cases to match.pd

[Richard Biener <richard dot guenther at gmail dot com>]

On Mon, Oct 19, 2015 at 12:48 PM, Richard Sandiford
<richard.sandiford@arm.com> wrote:
> Richard Sandiford <richard.sandiford@arm.com> writes:
>> Richard Sandiford <richard.sandiford@arm.com> writes:
>>> Marc Glisse <marc.glisse@inria.fr> writes:
>>>> On Thu, 15 Oct 2015, Richard Sandiford wrote:
>>>>
>>>>> This patch makes sure that, for every simplification that uses
>>>>> fold_strip_sign_ops, there are associated match.pd rules for the
>>>>> leaf sign ops, i.e. abs, negate and copysign.  A follow-on patch
>>>>> will add a pass to handle more complex cases.
>>>>>
>>>>> Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.
>>>>> OK to install?
>>>>>
>>>>> Thanks,
>>>>> Richard
>>>>>
>>>>>
>>>>> gcc/
>>>>>    * match.pd: Add rules to simplify ccos, ccosh, hypot, copysign
>>>>>    and x*x in cases where the operands are sign ops.  Extend these
>>>>>    rules to handle copysign as a sign op (including for cos, cosh
>>>>>    and pow, which already treated negate and abs as sign ops).
>>>>>
>>>>> diff --git a/gcc/match.pd b/gcc/match.pd
>>>>> index 83c48cd..4331df6 100644
>>>>> --- a/gcc/match.pd
>>>>> +++ b/gcc/match.pd
>>>>> @@ -61,6 +61,12 @@ along with GCC; see the file COPYING3.  If not see
>>>>> (define_operator_list TAN BUILT_IN_TANF BUILT_IN_TAN BUILT_IN_TANL)
>>>>> (define_operator_list COSH BUILT_IN_COSHF BUILT_IN_COSH BUILT_IN_COSHL)
>>>>> (define_operator_list CEXPI BUILT_IN_CEXPIF BUILT_IN_CEXPI BUILT_IN_CEXPIL)
>>>>> +(define_operator_list CCOS BUILT_IN_CCOSF BUILT_IN_CCOS BUILT_IN_CCOSL)
>>>>> +(define_operator_list CCOSH BUILT_IN_CCOSHF BUILT_IN_CCOSH BUILT_IN_CCOSHL)
>>>>> +(define_operator_list HYPOT BUILT_IN_HYPOTF BUILT_IN_HYPOT BUILT_IN_HYPOTL)
>>>>> +(define_operator_list COPYSIGN BUILT_IN_COPYSIGNF
>>>>> +                         BUILT_IN_COPYSIGN
>>>>> +                         BUILT_IN_COPYSIGNL)
>>>>>
>>>>> /* Simplifications of operations with one constant operand and
>>>>>    simplifications to constants or single values.  */
>>>>> @@ -321,7 +327,69 @@ along with GCC; see the file COPYING3.  If not see
>>>>>    (pows (op @0) REAL_CST@1)
>>>>>    (with { HOST_WIDE_INT n; }
>>>>>     (if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
>>>>> -     (pows @0 @1))))))
>>>>> +     (pows @0 @1)))))
>>>>> + /* Strip negate and abs from both operands of hypot.  */
>>>>> + (for hypots (HYPOT)
>>>>> +  (simplify
>>>>> +   (hypots (op @0) @1)
>>>>> +   (hypots @0 @1))
>>>>> +  (simplify
>>>>> +   (hypots @0 (op @1))
>>>>> +   (hypots @0 @1)))
>>>>
>>>> Out of curiosity, would hypots:c have worked? (it is probably not worth
>>>> gratuitously swapping the operands to save 3 lines though)
>>>
>>> Yeah, I think I'd prefer to keep it like it is if that's OK.
>>>
>>>>> + /* copysign(-x, y) and copysign(abs(x), y) -> copysign(x, y).  */
>>>>> + (for copysigns (COPYSIGN)
>>>>> +  (simplify
>>>>> +   (copysigns (op @0) @1)
>>>>> +   (copysigns @0 @1)))
>>>>> + /* -x*-x and abs(x)*abs(x) -> x*x.  Should be valid for all types.  */
>>>>> + (simplify
>>>>> +  (mult (op @0) (op @1))
>>>>> +  (mult @0 @0)))
>>>>
>>>> Typo @1 -> @0 ?
>>>
>>> Argh!  Thanks for catching that.  Wonder how many proof-reads that
>>> escaped :-(
>>>
>>>> This will partially duplicate Naveen's patch "Move some bit and binary
>>>> optimizations in simplify and match".
>>>
>>> OK.  Should I just limit it to the abs case?
>>>
>>>>> +/* copysign(x,y)*copysign(x,y) -> x*x.  */
>>>>> +(for copysigns (COPYSIGN)
>>>>> + (simplify
>>>>> +  (mult (copysigns @0 @1) (copysigns @0 @1))
>>>>
>>>> (mult (copysigns@2 @0 @1) @2)
>>>> ? Or is there some reason not to rely on CSE? (I don't think copysign has
>>>> any errno issue)
>>>
>>> No, simply didn't know about that trick.  I'll use it for the
>>> (mult (op @0) (op @0)) case as well.
>>
>> Here's the updated patch.  I've kept the (mult (negate@1 @0) @1)
>> pattern for now, but can limit it to abs as necessary when
>> Naveen's patch goes in.
>>
>> Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.
>>
>> Thanks,
>> Richard
>
> Er...
>
> gcc/
>         * match.pd: Add rules to simplify ccos, ccosh, hypot, copysign
>         and x*x in cases where the operands are sign ops.  Extend these
>         rules to handle copysign as a sign op (including for cos, cosh
>         and pow, which already treated negate and abs as sign ops).

Ok.

Thanks,
Richard.

> diff --git a/gcc/match.pd b/gcc/match.pd
> index f3813d8..d677e69 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -61,6 +61,12 @@ along with GCC; see the file COPYING3.  If not see
>  (define_operator_list TAN BUILT_IN_TANF BUILT_IN_TAN BUILT_IN_TANL)
>  (define_operator_list COSH BUILT_IN_COSHF BUILT_IN_COSH BUILT_IN_COSHL)
>  (define_operator_list CEXPI BUILT_IN_CEXPIF BUILT_IN_CEXPI BUILT_IN_CEXPIL)
> +(define_operator_list CCOS BUILT_IN_CCOSF BUILT_IN_CCOS BUILT_IN_CCOSL)
> +(define_operator_list CCOSH BUILT_IN_CCOSHF BUILT_IN_CCOSH BUILT_IN_CCOSHL)
> +(define_operator_list HYPOT BUILT_IN_HYPOTF BUILT_IN_HYPOT BUILT_IN_HYPOTL)
> +(define_operator_list COPYSIGN BUILT_IN_COPYSIGNF
> +                              BUILT_IN_COPYSIGN
> +                              BUILT_IN_COPYSIGNL)
>
>  /* Simplifications of operations with one constant operand and
>     simplifications to constants or single values.  */
> @@ -322,7 +328,69 @@ along with GCC; see the file COPYING3.  If not see
>     (pows (op @0) REAL_CST@1)
>     (with { HOST_WIDE_INT n; }
>      (if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
> -     (pows @0 @1))))))
> +     (pows @0 @1)))))
> + /* Strip negate and abs from both operands of hypot.  */
> + (for hypots (HYPOT)
> +  (simplify
> +   (hypots (op @0) @1)
> +   (hypots @0 @1))
> +  (simplify
> +   (hypots @0 (op @1))
> +   (hypots @0 @1)))
> + /* copysign(-x, y) and copysign(abs(x), y) -> copysign(x, y).  */
> + (for copysigns (COPYSIGN)
> +  (simplify
> +   (copysigns (op @0) @1)
> +   (copysigns @0 @1)))
> + /* -x*-x and abs(x)*abs(x) -> x*x.  Should be valid for all types.  */
> + (simplify
> +  (mult (op@1 @0) @1)
> +  (mult @0 @0)))
> +
> +/* cos(copysign(x, y)) -> cos(x).  Similarly for cosh.  */
> +(for coss (COS COSH)
> +     copysigns (COPYSIGN)
> + (simplify
> +  (coss (copysigns @0 @1))
> +   (coss @0)))
> +
> +/* pow(copysign(x, y), z) -> pow(x, z) if z is an even integer.  */
> +(for pows (POW)
> +     copysigns (COPYSIGN)
> + (simplify
> +  (pows (copysigns @0 @1) REAL_CST@1)
> +  (with { HOST_WIDE_INT n; }
> +   (if (real_isinteger (&TREE_REAL_CST (@1), &n) && (n & 1) == 0)
> +    (pows @0 @1)))))
> +
> +(for hypots (HYPOT)
> +     copysigns (COPYSIGN)
> + /* hypot(copysign(x, y), z) -> hypot(x, z).  */
> + (simplify
> +  (hypots (copysigns @0 @1) @2)
> +  (hypots @0 @2))
> + /* hypot(x, copysign(y, z)) -> hypot(x, y).  */
> + (simplify
> +  (hypots @0 (copysigns @1 @2))
> +  (hypots @0 @1)))
> +
> +/* copysign(copysign(x, y), z) -> copysign(x, z).  */
> +(for copysigns (COPYSIGN)
> + (simplify
> +  (copysigns (copysigns @0 @1) @2)
> +  (copysigns @0 @2)))
> +
> +/* copysign(x,y)*copysign(x,y) -> x*x.  */
> +(for copysigns (COPYSIGN)
> + (simplify
> +  (mult (copysigns@2 @0 @1) @2)
> +  (mult @0 @0)))
> +
> +/* ccos(-x) -> ccos(x).  Similarly for ccosh.  */
> +(for ccoss (CCOS CCOSH)
> + (simplify
> +  (ccoss (negate @0))
> +   (ccoss @0)))
>
>  /* X % Y is smaller than Y.  */
>  (for cmp (lt ge)
>