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Re: Fix ccos, csin, ccosh, csinh overflows (bug 14123)

From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
To: libc-alpha at sourceware dot org
Date: Sat, 19 May 2012 12:34:34 -0300
Subject: Re: Fix ccos, csin, ccosh, csinh overflows (bug 14123)
References: <Pine.LNX.4.64.1205182309020.10489@digraph.polyomino.org.uk> <20120519.003446.333274151145552811.davem@davemloft.net>
On 05/19/2012 01:34 AM, David Miller wrote:
> From: "Joseph S. Myers" <joseph@codesourcery.com>
> Date: Fri, 18 May 2012 23:10:42 +0000 (UTC)
>
>> Bug 14123 is that ccos, csin, ccosh and csinh have internal overflows
>> similar to those I fixed for cexp (bug 13892) and ctan/ctanh (bug
>> 11521).  The same technique for fixing them applies: if an overflowing
>> sinh or cosh value might be multiplied by a sin or cos value
>> (magnitude less than 1) to produce a non-overflowing result, split the
>> sinh or cosh computation into multiple non-overflowing exp
>> computations.
>>
>> I propose this patch fixing these overflows that way.  (Note that ccos
>> is implemented in terms of ccosh so does not need fixing separately.)
>> Tested x86 and x86_64 and ulps updated accordingly.  Ports note: m68k
>> has its own versions of these functions that will need fixing
>> similarly.
> Joseph could you please integrate the following Sparc ulps update
> into your changes?
>
> Thanks.
If you want to integrate, the PowerPC ulp update is below:

---

diff --git a/sysdeps/powerpc/fpu/libm-test-ulps b/sysdeps/powerpc/fpu/libm-test-ulps
index 5abff41..eac59ce 100644
--- a/sysdeps/powerpc/fpu/libm-test-ulps
+++ b/sysdeps/powerpc/fpu/libm-test-ulps
@@ -586,6 +586,22 @@ double: 1
 idouble: 1
 
 # ccos
+Test "Imaginary part of: ccos (-0.75 + 710.5 i) == 1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccos (-0.75 - 710.5 i) == 1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccos (-0.75 + 89.5 i) == 2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccos (-0.75 - 89.5 i) == 2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
 Test "Imaginary part of: ccos (-2 - 3 i) == -4.18962569096880723013255501961597373 - 9.10922789375533659797919726277886212 i":
 float: 1
 ifloat: 1
@@ -597,8 +613,43 @@ ifloat: 1
 Test "Imaginary part of: ccos (0.75 + 1.25 i) == 1.38173873063425888530729933139078645 - 1.09193013555397466170919531722024128 i":
 float: 1
 ifloat: 1
+Test "Imaginary part of: ccos (0.75 + 89.5 i) == 2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccos (0.75 - 89.5 i) == 2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccos (0.75 + 710.5 i) == 1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccos (0.75 - 710.5 i) == 1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccos (0x1p-1074 + 1440 i) == inf - 5.981479269486130556466515778180916082415e301 i plus overflow exception":
+double: 1
+idouble: 1
 
 # ccosh
+Test "Imaginary part of: ccosh (-710.5 + 0.75 i) == 1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccosh (-710.5 - 0.75 i) == 1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccosh (-89.5 + 0.75 i) == 2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccosh (-89.5 - 0.75 i) == 2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
 Test "Real part of: ccosh (-2 - 3 i) == -3.72454550491532256547397070325597253 + 0.511822569987384608834463849801875634 i":
 float: 1
 ifloat: 1
@@ -617,6 +668,25 @@ float: 1
 ifloat: 1
 ildouble: 2
 ldouble: 2
+Test "Imaginary part of: ccosh (89.5 + 0.75 i) == 2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccosh (89.5 - 0.75 i) == 2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: ccosh (710.5 + 0.75 i) == 1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccosh (710.5 - 0.75 i) == 1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: ccosh (1440 + 0x1p-1074 i) == inf + 5.981479269486130556466515778180916082415e301 i plus overflow exception":
+double: 1
+idouble: 1
 
 # cexp
 Test "Imaginary part of: cexp (-2.0 - 3.0 i) == -0.13398091492954261346140525546115575 - 0.019098516261135196432576240858800925 i":
@@ -1077,7 +1147,60 @@ ifloat: 2
 ildouble: 2
 ldouble: 2
 
+# csin
+Test "Real part of: csin (-0.75 + 710.5 i) == -1.255317763348154410745082950806112487736e308 + 1.347490911916428129246890157395342279438e308 i":
+double: 1
+idouble: 1
+Test "Real part of: csin (-0.75 - 710.5 i) == -1.255317763348154410745082950806112487736e308 - 1.347490911916428129246890157395342279438e308 i":
+double: 1
+idouble: 1
+Test "Real part of: csin (-0.75 + 89.5 i) == -2.522786001038096774676288412995370563339e38 + 2.708024460708609732016532185663087200560e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Real part of: csin (-0.75 - 89.5 i) == -2.522786001038096774676288412995370563339e38 - 2.708024460708609732016532185663087200560e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Real part of: csin (0.75 + 89.5 i) == 2.522786001038096774676288412995370563339e38 + 2.708024460708609732016532185663087200560e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Real part of: csin (0.75 - 89.5 i) == 2.522786001038096774676288412995370563339e38 - 2.708024460708609732016532185663087200560e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Real part of: csin (0.75 + 710.5 i) == 1.255317763348154410745082950806112487736e308 + 1.347490911916428129246890157395342279438e308 i":
+double: 1
+idouble: 1
+Test "Real part of: csin (0.75 - 710.5 i) == 1.255317763348154410745082950806112487736e308 - 1.347490911916428129246890157395342279438e308 i":
+double: 1
+idouble: 1
+Test "Real part of: csin (0x1p-1074 + 1440 i) == 5.981479269486130556466515778180916082415e301 + inf i plus overflow exception":
+double: 1
+idouble: 1
+
 # csinh
+Test "Imaginary part of: csinh (-710.5 + 0.75 i) == -1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: csinh (-710.5 - 0.75 i) == -1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: csinh (-89.5 + 0.75 i) == -2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: csinh (-89.5 - 0.75 i) == -2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
 Test "Imaginary part of: csinh (-2 - 3 i) == 3.59056458998577995201256544779481679 - 0.530921086248519805267040090660676560 i":
 double: 1
 idouble: 1
@@ -1093,6 +1216,26 @@ float: 1
 ifloat: 1
 ildouble: 1
 ldouble: 1
+float: 1
+Test "Imaginary part of: csinh (89.5 + 0.75 i) == 2.708024460708609732016532185663087200560e38 + 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: csinh (89.5 - 0.75 i) == 2.708024460708609732016532185663087200560e38 - 2.522786001038096774676288412995370563339e38 i":
+float: 1
+ifloat: 1
+ldouble: 1
+ildouble: 1
+Test "Imaginary part of: csinh (710.5 + 0.75 i) == 1.347490911916428129246890157395342279438e308 + 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: csinh (710.5 - 0.75 i) == 1.347490911916428129246890157395342279438e308 - 1.255317763348154410745082950806112487736e308 i":
+double: 1
+idouble: 1
+Test "Imaginary part of: csinh (1440 + 0x1p-1074 i) == inf + 5.981479269486130556466515778180916082415e301 i plus overflow exception":
+double: 1
+idouble: 1
 
 # csqrt
 Test "Real part of: csqrt (-2 + 3 i) == 0.89597747612983812471573375529004348 + 1.6741492280355400404480393008490519 i":
@@ -2333,6 +2476,7 @@ ldouble: 1
 Function: Real part of "ccos":
 double: 1
 float: 1
+double: 1
 idouble: 1
 ifloat: 1
 ildouble: 1
@@ -2341,6 +2485,8 @@ ldouble: 1
 Function: Imaginary part of "ccos":
 float: 1
 ifloat: 1
+double: 1
+idouble: 1
 ildouble: 1
 ldouble: 1
 
@@ -2355,6 +2501,8 @@ ldouble: 1
 Function: Imaginary part of "ccosh":
 float: 1
 ifloat: 1
+double: 1
+idouble: 1
 ildouble: 2
 ldouble: 2
 
@@ -2483,9 +2631,17 @@ ildouble: 1
 ldouble: 1
 
 Function: Real part of "csin":
+float: 1
+ifloat: 1
+double: 1
+idouble: 1
 ildouble: 1
 ldouble: 1
 
+Function: Imaginary part of "csin":
+ldouble: 1
+ildouble: 1
+
 Function: Real part of "csinh":
 float: 1
 ifloat: 1


-- 
Adhemerval Zanella Netto
  Software Engineer
  Linux Technology Center Brazil
  Toolchain / GLIBC on Power Architecture
  azanella@linux.vnet.ibm.com / azanella@br.ibm.com
  +55 61 8642-9890
References:
- Fix ccos, csin, ccosh, csinh overflows (bug 14123)
  - From: Joseph S. Myers
- Re: Fix ccos, csin, ccosh, csinh overflows (bug 14123)
  - From: David Miller
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