I repeated the same tests for Python 3.7 on PR 11264.

I replaced "38" with "37" and "3.8" and 3.7" and my 3 scripts :-) I modified step1.sh for PGO+LTO with -O0:

set -x -e
git clean -fdx
./configure CC=clang --with-lto --prefix /opt/py37 --enable-optimizations
sed -i -e 's/^PROFILE_TASK=.*/PROFILE_TASK=-c pass/' Makefile
sed -i -e 's/-O3/-O0/' Makefile
make 2>&1|tee log
grep -E -- '-o python|-o Python/bltinmodule.o|Modules/_asynciomodule.o' log|grep -c lto
# 4 expected: -flto passed to compiler *and* linker


Test results:

./configure CC=clang --with-lto --prefix /opt/py38

(1) 4
(2) 0, False => OK!
(3) 0 => OK!

./configure CC=clang --with-lto --enable-shared

(1) 4
(2) 0, False => OK!
(3) 0 => OK!

./configure CC=clang --with-lto --enable-optimizations

(1) 8 => OK!
(2) 0, False => OK!
(3) 0 => OK!