From: Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br>
To: Paul Koning <paulkoning@comcast.net>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Add sinh(tanh(x)) and cosh(tanh(x)) rules
Date: Wed, 08 Aug 2018 18:57:00 -0000 [thread overview]
Message-ID: <CAEFO=4CLNqEVyVnsE0ZkGwrAc289p+Vowe3MeGzuUaJRjHib-w@mail.gmail.com> (raw)
In-Reply-To: <7AC47F39-364E-4D7D-BC01-690761CA2F09@comcast.net>
Sorry about that. In the e-mail text field I wrote sinh(tanh(x)) and
cosh(tanh(x)) where it was supposed to be sinh(atanh(x)) and
cosh(atanh(x)), thus I am talking about the inverse hyperbolic tangent
function. The patch code and comments are still correct.
On Wed, Aug 8, 2018 at 10:58 AM, Paul Koning <paulkoning@comcast.net> wrote:
> Now I'm puzzled.
>
> I don't see how an infinite would show up in the original expression. I don't know hyperbolic functions, so I just constructed a small test program, and the original vs. the substitution you mention are not at all similar.
>
> paul
>
>
>> On Aug 7, 2018, at 4:42 PM, Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br> wrote:
>>
>> That is a good question because I didn't know that such targets
>> exists. Any suggestion?
>>
>>
>> On Tue, Aug 7, 2018 at 5:29 PM, Paul Koning <paulkoning@comcast.net> wrote:
>>>
>>>
>>>> On Aug 7, 2018, at 4:00 PM, Giuliano Augusto Faulin Belinassi <giuliano.belinassi@usp.br> wrote:
>>>>
>>>> Related with bug 86829, but for hyperbolic trigonometric functions.
>>>> This patch adds substitution rules to both sinh(tanh(x)) -> x / sqrt(1
>>>> - x*x) and cosh(tanh(x)) -> 1 / sqrt(1 - x*x). Notice that the both
>>>> formulas has division by 0, but it causes no harm because 1/(+0) ->
>>>> +infinity, thus the math is still safe.
>>>
>>> What about non-IEEE targets that don't have "infinite" in their float representation?
>>>
>>> paul
>>>
>>>
>
next prev parent reply other threads:[~2018-08-08 18:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 20:00 Giuliano Augusto Faulin Belinassi
2018-08-07 20:29 ` Paul Koning
2018-08-07 20:42 ` Giuliano Augusto Faulin Belinassi
2018-08-08 13:59 ` Paul Koning
2018-08-08 18:57 ` Giuliano Augusto Faulin Belinassi [this message]
2018-08-08 19:55 ` Paul Koning
2018-10-12 4:55 ` Jeff Law
2018-10-12 14:55 ` Giuliano Augusto Faulin Belinassi
2018-10-16 21:16 ` Jeff Law
2018-10-17 21:43 ` Giuliano Augusto Faulin Belinassi
2018-10-17 22:45 ` Jeff Law
2018-10-18 5:38 ` Giuliano Augusto Faulin Belinassi
2018-10-18 17:10 ` Jeff Law
2018-10-18 22:46 ` Giuliano Belinassi
2018-10-18 23:22 Wilco Dijkstra
2018-10-19 13:39 ` Giuliano Augusto Faulin Belinassi
2018-10-19 13:46 ` Wilco Dijkstra
2018-10-19 14:49 ` Jakub Jelinek
2018-10-19 15:35 ` Wilco Dijkstra
2018-10-19 14:03 ` Segher Boessenkool
2018-10-19 15:10 ` Giuliano Augusto Faulin Belinassi
2018-10-19 17:28 ` Wilco Dijkstra
2018-10-20 19:06 ` Giuliano Augusto Faulin Belinassi
2018-10-22 20:58 ` Jeff Law
2018-10-23 9:52 ` Richard Biener
2018-10-23 11:31 ` Wilco Dijkstra
2018-10-23 11:35 ` Jakub Jelinek
2018-10-23 12:02 ` Wilco Dijkstra
2018-11-07 22:21 ` Jeff Law
2018-11-07 22:34 ` Wilco Dijkstra
2018-11-08 1:44 ` Segher Boessenkool
2018-11-08 13:33 ` Wilco Dijkstra
2018-11-09 20:04 ` Jeff Law
2018-11-09 22:04 ` Giuliano Augusto Faulin Belinassi
2018-11-10 5:36 ` Segher Boessenkool
2018-11-12 14:17 ` Richard Biener
2018-12-02 14:37 ` Segher Boessenkool
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