JDK-8168503 modified hotspot.m4 and added a line break into the definition of $VALID_JVM_FEATURES. Unfortunately this exposes a bug in the AIX grep utility.

When called like this: "grep -Fx <patternlist>", AIX grep is unable to handle empty patterns correctly; it fails to match any pattern which directly precedes the empty pattern.

8168503 added a line break in the definition of a variable:

 VALID_JVM_FEATURES="compiler1 compiler2 zero shark minimal dtrace jvmti jvmci \
- graal fprof vm-structs jni-check services management all-gcs nmt cds static-build aot"
+ graal fprof vm-structs jni-check services management all-gcs nmt cds \
+ static-build link-time-opt aot"

So now, "cds" is followed by multiple spaces, which are later expanded to multiple newlines, and grep is now unable to match "cds". This causes the HOTSPOT_VALIDATE_JVM_FEATURES function to fail with "Invalid JVM feature: cds".

The error would also happened before JDK-8168503 when trying to match "jvmci", but so far we do not build jvmci on powerpc.