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* [newlib-cygwin] pow: fix pow(-1.0, NaN)
@ 2020-02-14 9:15 Corinna Vinschen
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From: Corinna Vinschen @ 2020-02-14 9:15 UTC (permalink / raw)
To: newlib-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=bb25dd1b0f39f343b764fd0db861cb9a30441407
commit bb25dd1b0f39f343b764fd0db861cb9a30441407
Author: Nicolas Brunie <nbrunie@kalray.eu>
Date: Fri Feb 14 10:12:25 2020 +0100
pow: fix pow(-1.0, NaN)
I think I may have encountered a bug in the implementation of pow:
pow(-1.0, NaN) returns 1.0 when it should return NaN.
Because ix is used to check input vs 1.0 rather than hx, -1.0 is
mistaken for 1.0
Diff:
---
newlib/libm/math/e_pow.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/newlib/libm/math/e_pow.c b/newlib/libm/math/e_pow.c
index 6d2a501..5fd28e6 100644
--- a/newlib/libm/math/e_pow.c
+++ b/newlib/libm/math/e_pow.c
@@ -122,7 +122,7 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
/* x|y==NaN return NaN unless x==1 then return 1 */
if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) {
- if(((ix-0x3ff00000)|lx)==0) return one;
+ if(((hx-0x3ff00000)|lx)==0) return one;
else return nan("");
}
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2020-02-14 9:15 [newlib-cygwin] pow: fix pow(-1.0, NaN) Corinna Vinschen
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