ADDITIONAL SYSTEM INFORMATION :
~$ uname -a
Linux sandy 3.16.0-10-amd64 #1 SMP Debian 3.16.81-1 (2020-01-17) x86_64 GNU/Linux
~$ java -version
java version "14" 2020-03-17
Java(TM) SE Runtime Environment (build 14+36-1461)
Java HotSpot(TM) 64-Bit Server VM (build 14+36-1461, mixed mode, sharing)


A DESCRIPTION OF THE PROBLEM :
Math.cos() gives different results when intrinsics are disabled. For example, when intrinsics are enabled, Math.cos(-15.085052295396792) = -0.8121836333436737. When the _dcos intrinsic is disabled, Math.cos(-15.085052295396792) = -0.8121836333436738. One of these is not within 1 ulp of the actual result.

REGRESSION : Last worked in version 8u241

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the test case below.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expected both results to be equal.
ACTUAL -
The results differed in the last decimal place.

---------- BEGIN SOURCE ----------
public class Cosine {
  public static void main(String[]args) {
    System.out.println("Math.cos(-15.085052295396792) = " + Math.cos(-15.085052295396792));
  }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Disable intrinsics:
-XX:+UnlockDiagnosticVMOptions -XX:DisableIntrinsic=_dcos

FREQUENCY : always