When compiling with gcc 7.3 on s390x the following error occurs:
Compiling 5349 files for BUILD_DDR_CLASSES
../src/java.base/share/native/libfdlibm/k_rem_pio2.c: In function '__j__kernel_rem_pio2':
../src/java.base/share/native/libfdlibm/k_rem_pio2.c:255:27: error: array subscript is below array bounds [-Werror=array-bounds]
                 for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */
                         ~~^~~~~~
cc1: all warnings being treated as errors
gmake[3]: *** [/data/jenkins/workspace/openjdk11_openj9_build_s390x_linux/openjdk/build/linux-s390x-normal-server-release/support/native/java.base/libfdlibm/k_rem_pio2.o] Error 1

Also a similar error in mlib_ImageLookUp_Bit.c due to left shifting a negative value.