This report was due to a bug in comparison scripts, which is now fixed.

There are several functions named "contract<3>” in 447.dealII, and comparison picked sizes of different instances of the function.

-- Maxim Kuvyrkov https://www.linaro.org

On 15 Sep 2021, at 23:46, ci_notify@linaro.org wrote:

After llvm commit 1c3fcc8ae92ebfe9a9d1a21a288ad71ef7f98091 Author: Amy Kwan amy.kwan1@ibm.com

[libc++][NFC] Mark values in gdb pretty print comparison functions as live to prevent values being optimized out.

the following hot functions grew in size by more than 10% (but their benchmarks grew in size by less than 1%):

• 447.dealII,[.] contract<3> grew in size by 164%

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

This commit has regressed these CI configurations:

• tcwg_bmk_llvm_apm/llvm-release-aarch64-spec2k6-Oz

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-1c3fcc8ae92ebfe9a9d1a21a288ad71ef7f98091 cd investigate-llvm-1c3fcc8ae92ebfe9a9d1a21a288ad71ef7f98091

# 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 1c3fcc8ae92ebfe9a9d1a21a288ad71ef7f98091 ../artifacts/test.sh

# Reproduce last_good build git checkout --detach c8905f1bb304f1cfe297312ae0dda9946cb27594 ../artifacts/test.sh

cd ..

</cut>

Full commit (up to 1000 lines):

<cut> commit 1c3fcc8ae92ebfe9a9d1a21a288ad71ef7f98091 Author: Amy Kwan <amy.kwan1@ibm.com> Date: Fri Sep 3 14:53:57 2021 -0400

[libc++][NFC] Mark values in gdb pretty print comparison functions as live to prevent values being optimized out.

It appears when testing LLVM 13 on Power, we run into failures with the `libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp` test case optimizing values out.

Despite some the functions in the test already being marked with optnone, adding the `MarkAsLive()` calls inside of the pretty printer comparison functions resolves the issues of the values being optimized out.

This patch aims to address https://llvm.org/PR51675.

Differential Revision: https://reviews.llvm.org/D109204

(cherry picked from commit 217c6d643124be312f4a99b203118744edb9d54c)

libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp b/libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp index 2d8e9620089a..7c8d307d19fb 100644 --- a/libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp +++ b/libcxx/test/libcxx/gdb/gdb_pretty_printer_test.sh.cpp @@ -92,24 +92,28 @@ void MarkAsLive(Type &&) {} template <typename TypeToPrint> void ComparePrettyPrintToChars( TypeToPrint value, const char *expectation) {

• MarkAsLive(value); StopForDebugger(&value, &expectation);

}

template <typename TypeToPrint> void ComparePrettyPrintToRegex( TypeToPrint value, const char *expectation) {

• MarkAsLive(value); StopForDebugger(&value, &expectation);

}

void CompareExpressionPrettyPrintToChars( std::string value, const char *expectation) {

• MarkAsLive(value); StopForDebugger(&value, &expectation);

}

void CompareExpressionPrettyPrintToRegex( std::string value, const char *expectation) {

• MarkAsLive(value); StopForDebugger(&value, &expectation);

}

</cut>