Successfully identified regression in *llvm* in CI configuration tcwg_bmk_llvm_tx1/llvm-release-aarch64-spec2k6-O3_LTO. So far, this commit has regressed CI configurations: - tcwg_bmk_llvm_tx1/llvm-release-aarch64-spec2k6-O3_LTO

Culprit: <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 </cut>

Results regressed to (for first_bad == 669ddd1e9b1226432b003dbba05b99f8e992285b) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1 -- --set gcc_override_configure=--disable-libsanitizer: -8 # build_abe linux: -7 # build_abe glibc: -6 # build_abe stage2 -- --set gcc_override_configure=--disable-libsanitizer: -5 # build_llvm true: -3 # true: 0 # benchmark -- -O3_LTO artifacts/build-669ddd1e9b1226432b003dbba05b99f8e992285b/results_id: 1 # 473.astar,astar_base.default regressed by 106

from (for last_good == b15cbaf5a03d0b32dbc32c37766e32ccf66e6c87) # reset_artifacts: -10 # build_abe binutils: -9 # build_abe stage1 -- --set gcc_override_configure=--disable-libsanitizer: -8 # build_abe linux: -7 # build_abe glibc: -6 # build_abe stage2 -- --set gcc_override_configure=--disable-libsanitizer: -5 # build_llvm true: -3 # true: 0 # benchmark -- -O3_LTO artifacts/build-b15cbaf5a03d0b32dbc32c37766e32ccf66e6c87/results_id: 1

Artifacts of last_good build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-... Results ID of last_good: tx1_64/tcwg_bmk_llvm_tx1/bisect-llvm-release-aarch64-spec2k6-O3_LTO/3543 Artifacts of first_bad build: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-... Results ID of first_bad: tx1_64/tcwg_bmk_llvm_tx1/bisect-llvm-release-aarch64-spec2k6-O3_LTO/3539 Build top page/logs: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-...

Configuration details:

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

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

mkdir -p artifacts/manifests curl -o artifacts/manifests/build-baseline.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-... --fail curl -o artifacts/manifests/build-parameters.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-... --fail curl -o artifacts/test.sh https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-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>

History of pending regressions and results: https://git.linaro.org/toolchain/ci/base-artifacts.git/log/?h=linaro-local/c...

Artifacts: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-... Build log: https://ci.linaro.org/job/tcwg_bmk_ci_llvm-bisect-tcwg_bmk_tx1-llvm-release-...

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>