Created attachment 325265 [details]
Test case for incorrect value of cos()

Description of problem:
The attached test case produces the erroneous value of -20763584.029346 for
cos(Pi / 2) when the rounding mode is set to FE_UPWARD, instead of the
correct value (close to) 0. Other rounding modes do not show this error,
compiling with optimization enabled (-O1, -O2 or -O3) or as a 32 bit binary
with -m32 also do not show the error. If the binary is linked statically with
-static, the bug disappears as well.


Version-Release number of selected component (if applicable):

gcc (GCC) 4.3.0 20080428 (Red Hat 4.3.0-8)
glibc-2.8-8.x86_64 (Build Date: Thu Jul 17 00:31:06 2008)


How reproducible:

Steps to Reproduce:
1.Compile attached test case with
gcc -O0 -o cos_bug cos_bug.c -lm

2. run "./cos_bug"

  
Actual results:

Prints 
x = 1.57079632679489655800 = 0x1.921fb54442d18p+0
cos(x) = -20763584.029346


Expected results:

cos(x) should be a value close to 0.


Additional info:

Processor is Intel(R) Core(TM)2 CPU 6400  @ 2.13GHz.

May be related to bug #88513