Dear contributor, our automatic CI has detected problems related to your patch(es).  Please find some details below.  If you have any questions, please follow up on linaro-toolchain@lists.linaro.org mailing list, Libera's #linaro-tcwg channel, or ping your favourite Linaro toolchain developer on the usual project channel.

In CI config tcwg_bmk-code_speed-cpu2017rate/llvm-arm-master-O2 after:

  | baseline build

the following hot functions slowed down by more than 15% (but their benchmarks slowed down by less than 3%):
- slowed down by 50% - 544.nab_r:libc.so.6 - from 2 to 3 perf samples
- slowed down by 100% - 544.nab_r:[.] __vfscanf_internal - from 1 to 2 perf samples

The configuration of this build is:
Below reproducer instructions can be used to re-build both "first_bad" and "last_good" cross-toolchains used in this bisection.  Naturally, the scripts will fail when triggerring benchmarking jobs if you don\'t have access to Linaro TCWG CI.

Configuration:
- Benchmark: SPEC CPU2017
- Toolchain: Clang + Glibc + LLVM Linker
- Version: all components were built from their tip of trunk
- Target: arm-linux-gnueabihf
- Compiler flags: O2
- Hardware: NVidia TK1 4x Cortex-A15

This benchmarking CI is work-in-progress, and we welcome feedback and suggestions at linaro-toolchain@lists.linaro.org .  In our improvement plans is to add support for SPEC CPU2017 benchmarks and provide "perf report/annotate" data behind these reports.

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The information below can be used to reproduce a debug environment:

Current build   : https://ci.linaro.org/job/tcwg_bmk-code_speed-cpu2017rate--llvm-arm-master-O2-build/93/artifact/artifacts
Reference build : https://ci.linaro.org/job/tcwg_bmk-code_speed-cpu2017rate--llvm-arm-master-O2-build/91/artifact/artifacts