Code-speed regressions from tcwg_bmk-llvm CI

523.xalancbmk_r failed to run
Details: https://ci.linaro.org/job/tcwg_bmk-code_speed-cpu2017rate--llvm-arm-master-O2_LTO-build/295/artifact/artifacts/notify/mail-body.txt/*view*/

523.xalancbmk_r failed to run
Details: https://ci.linaro.org/job/tcwg_bmk-code_speed-cpu2017rate--llvm-arm-master-O3_LTO-build/327/artifact/artifacts/notify/mail-body.txt/*view*/

https://linaro.atlassian.net/browse/LLVM-1501
slowed down by 4% - 638.imagick_s
Details: https://ci.linaro.org/job/tcwg_bmk-fujitsu_speed-cpu2017speed--llvm-aarch64-master-O3-build/612/artifact/artifacts/notify/mail-body.txt/*view*/

https://linaro.atlassian.net/browse/LLVM-1417
slowed down by 13% - 549.fotonik3d_r
Details: https://ci.linaro.org/job/tcwg_bmk-qc_speed-cpu2017rate--llvm-aarch64-master-O3-build/639/artifact/artifacts/notify/mail-body.txt/*view*/

https://linaro.atlassian.net/browse/LLVM-1373
slowed down by 32% - 520.omnetpp_r:libc.so.6
Details: https://ci.linaro.org/job/tcwg_bmk-qc_speed-cpu2017rate--llvm-aarch64-master-O3-build/602/artifact/artifacts/notify/mail-body.txt/*view*/