Extended Description

These errors happen when building Firefox with clang and targeting s390x:

[ 553s] 6:08.70 In file included from /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/md/unix/xptcstubs_linux_s390x.cpp:194:
[ 553s] 6:08.70 /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/xptcstubsdef.inc:2:1: error: invalid use of length addressing
[ 553s] 6:08.70 STUB_ENTRY(4)
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/md/unix/xptcstubs_linux_s390x.cpp:167:9: note: expanded from macro 'STUB_ENTRY'
[ 553s] 6:08.70 "lg %0,0(15)\n\t"
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 :1:13: note: instantiated into assembly here
[ 553s] 6:08.70 lg %r1,0(15)
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 In file included from /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/md/unix/xptcstubs_linux_s390x.cpp:194:
[ 553s] 6:08.70 /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/xptcstubsdef.inc:2:1: error: invalid operand for instruction
[ 553s] 6:08.70 STUB_ENTRY(4)
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/md/unix/xptcstubs_linux_s390x.cpp:168:25: note: expanded from macro 'STUB_ENTRY'
[ 553s] 6:08.70 "aghi %0,160\n\t"
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 :3:9: note: instantiated into assembly here
[ 553s] 6:08.70 stmg 3,6,0(%r14)
[ 553s] 6:08.70 ^
[ 553s] 6:08.70 In file included from /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/md/unix/xptcstubs_linux_s390x.cpp:194:
[ 553s] 6:08.70 /home/abuild/rpmbuild/BUILD/firefox-68.0/xpcom/reflect/xptcall/xptcstubsdef.inc:2:1: error: invalid operand for instruction
[ 553s] 6:08.70 STUB_ENTRY(4)
...

This builds fine with -fno-integrated-as.