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Subject: Re: [PATCH 4/4] Use copysign instead of ternary for some sin/cos
 input ranges
To: Manfred <mx2927@gmail.com>, libc-alpha@sourceware.org
References: <1474998553-2366-1-git-send-email-siddhesh@sourceware.org>
 <1474998553-2366-5-git-send-email-siddhesh@sourceware.org>
 <343e148d-c0ce-c506-a040-a80301856af4@gmail.com>
From: Carlos O'Donell <carlos@redhat.com>
Message-ID: <e4c99102-6712-1869-d7ff-3eaf3dda1259@redhat.com>
Date: Wed, 28 Sep 2016 20:04:00 -0000
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On 09/28/2016 08:59 AM, Manfred wrote:
> 
> 
> On 9/27/2016 7:49 PM, Siddhesh Poyarekar wrote:
>> @@ -479,7 +479,7 @@ __sin (double x)
>>      {
>>        res = do_sin (x, 0, &cor);
>>        retval = (res == res + 1.096 * cor) ? res : slow1 (x);
>> -      retval = m > 0 ? retval : -retval;
>> +      retval = __copysign (retval, x);
>>      }                /*   else  if (k < 0x3feb6000)    */
>>
> The ternary uses m, __copysign uses x. It could be correct (I didn't check the full context), but just in case...

In both those cases X < pi, and therefore the result has the same sign as X.

-- 
Cheers,
Carlos.