After llvm commit 669ddd1e9b1226432b003dbba05b99f8e992285b Author: Arthur Eubanks aeubanks@google.com

Turn on the new pass manager by default

the following benchmarks grew in size by more than 1%: - 403.gcc grew in size by 2% from 2586180 to 2648252 bytes

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.

For your convenience, we have uploaded tarballs with pre-processed source and assembly files at: - First_bad save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... - Last_good save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... - Baseline save-temps: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-...

Configuration: - Benchmark: SPEC CPU2006 - Toolchain: Clang + Glibc + LLVM Linker - Version: all components were built from their latest release branch - Target: aarch64-linux-gnu - Compiler flags: -Os -flto - Hardware: APM Mustang 8x X-Gene1

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.

THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.

This commit has regressed these CI configurations: - tcwg_bmk_llvm_apm/llvm-release-aarch64-spec2k6-Os_LTO

First_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... Last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... Baseline build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... Even more details: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-...

Reproduce builds: <cut> mkdir investigate-llvm-669ddd1e9b1226432b003dbba05b99f8e992285b cd investigate-llvm-669ddd1e9b1226432b003dbba05b99f8e992285b

# Fetch scripts git clone https://git.linaro.org/toolchain/jenkins-scripts

# Fetch manifests and test.sh script mkdir -p artifacts/manifests curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... --fail curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... --fail curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_apm-llvm-release-... --fail chmod +x artifacts/test.sh

# Reproduce the baseline build (build all pre-requisites) ./jenkins-scripts/tcwg_bmk-build.sh @@ artifacts/manifests/build-baseline.sh

# Save baseline build state (which is then restored in artifacts/test.sh) mkdir -p ./bisect rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/ --exclude /llvm/ ./ ./bisect/baseline/

cd llvm

# Reproduce first_bad build git checkout --detach 669ddd1e9b1226432b003dbba05b99f8e992285b ../artifacts/test.sh

# Reproduce last_good build git checkout --detach b15cbaf5a03d0b32dbc32c37766e32ccf66e6c87 ../artifacts/test.sh

cd .. </cut>

Full commit (up to 1000 lines): <cut> commit 669ddd1e9b1226432b003dbba05b99f8e992285b Author: Arthur Eubanks aeubanks@google.com Date: Mon Jan 25 11:00:56 2021 -0800

Turn on the new pass manager by default

This turns on the new pass manager by default for the optimization pipeline in Clang and ThinLTO in various LLD backends. This also makes uses of `opt -instcombine` use the new pass manager (unless specifically opted out).

This does not affect the backend target-dependent codegen pipeline.

If this causes regressions, you can opt out of the new pass manager either via the -DENABLE_EXPERIMENTAL_NEW_PASS_MANAGER=OFF CMake flag while building LLVM, or via various compiler flags, e.g. -flegacy-pass-manager for Clang or -Wl,--lto-legacy-pass-manager for ELF LLD. Please file bugs for any regressions.

Major differences: * The inliner works slightly differently * -O1 does some amount of inlining * LCSSA and LoopSimplify are run before all loop passes * Loop unswitching is implemented slightly differently * A new SpeculateAroundPHIs pass is added to the pipeline

https://lists.llvm.org/pipermail/llvm-dev/2021-January/148098.html

Reviewed By: asbirlea, ychen, MaskRay, echristo

Differential Revision: https://reviews.llvm.org/D95380 --- llvm/CMakeLists.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt index 1affc289e64b..f5298de9f7ca 100644 --- a/llvm/CMakeLists.txt +++ b/llvm/CMakeLists.txt @@ -688,8 +688,8 @@ else() endif() option(LLVM_ENABLE_PLUGINS "Enable plugin support" ${LLVM_ENABLE_PLUGINS_default})

-set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER FALSE CACHE BOOL - "Enable the experimental new pass manager by default.") +set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER TRUE CACHE BOOL + "Enable the new pass manager by default.")

include(HandleLLVMOptions)

</cut>