[Bug ipa/63576] [5 Regression] ICE : in ipa_merge_profiles, at ipa-utils.c:540 during Firefox LTO/PGO build

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63576

--- Comment #9 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
I will give your patch a try.
In case it might help here's the script I use for LTO/PGO
(as you can see it starts the instrumented browser. I then
just visit a couple of webpages to train it):

markus@x4 mozilla-central % cat profile_build
#!/bin/zsh
mv .mozconfig .mozconfig_tmp && 
cp .mozconfig_profile_gen .mozconfig && 
nice -n 19 make -f client.mk && 
killall firefox 
/var/tmp/moz-build-dir/dist/bin/firefox && 
rm  /var/tmp/moz-build-dir/**/Makefile && 
rm  /var/tmp/moz-build-dir/**/*.o && 
rm  /var/tmp/moz-build-dir/**/config.status && 
rm  /var/tmp/moz-build-dir/**/configure.pkl && 
cp .mozconfig_profile_use .mozconfig && 
nice -n 19 make -f client.mk && 
make DESTDIR=/var/tmp/firefox-destdir -C /var/tmp/moz-build-dir install && 
rm -fr /var/tmp/moz-build-dir 
mv .mozconfig_tmp .mozconfig

Where .mozconfig_profile_gen contains:
export CFLAGS="-march=native -fno-semantic-interposition -ffunction-sections
-fdata-sections" 
export CXXFLAGS="-march=native -fno-semantic-interposition -fprofile-generate
-ffunction-sections -fdata-sections"

and .mozconfig_profile_use contains:
export CFLAGS="-march=native -fno-semantic-interposition -ffunction-sections
-fdata-sections"
export CXXFLAGS="-march=native -fno-semantic-interposition -flto=4
-fdevirtualize-at-ltrans -fprofile-use -fprofile-correction -ffunction-sections
-fdata-sections"