On x86-64, r264546 caused:

libtool: compile:  /export/build/gnu/tools-build/gcc-x32-debug/build-x86_64-linux/./gcc/gccgo -B/export/build/gnu/tools-build/gcc-x32-debug/build-x86_64-linux/./gcc/ -B/usr/gcc-9.0.0-x32/x86_64-pc-linux-gnu/bin/ -B/usr/gcc-9.0.0-x32/x86_64-pc-linux-gnu/lib/ -isystem /usr/gcc-9.0.0-x32/x86_64-pc-linux-gnu/include -isystem /usr/gcc-9.0.0-x32/x86_64-pc-linux-gnu/sys-include -minline-all-stringops -O2 -g -mx32 -I . -c -fgo-pkgpath=runtime -fgo-c-header=runtime.inc.raw -fgo-compiling-runtime /export/gnu/import/git/sources/gcc/libgo/go/runtime/alg.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/atomic_pointer.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/cgo_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/cgocall.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/cgocheck.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/chan.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/compiler.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/cpuprof.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/cputicks.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/debug.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/env_posix.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/error.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/extern.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/fastlog2.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/fastlog2table.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/ffi.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/float.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/hash64.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/heapdump.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/iface.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/lfstack.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/lfstack_64bit.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/lock_futex.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/malloc.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/map.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/map_fast32.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/map_fast64.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/map_faststr.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mbarrier.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mbitmap.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mcache.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mcentral.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mem_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mfinal.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mfixalloc.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgc.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgc_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgclarge.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgcmark.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgcsweep.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgcsweepbuf.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mgcwork.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mheap.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mprof.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/msan0.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/msize.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mstats.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/mwbbuf.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/netpoll.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/netpoll_epoll.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/os_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/os_linux.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/os_linux_noauxv.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/panic.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/print.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/proc.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/profbuf.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/proflabel.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/race0.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/rdebug.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/relax_stub.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/runtime.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/runtime1.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/runtime2.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/rwmutex.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/select.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/sema.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/signal_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/signal_sighandler.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/signal_unix.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/sigqueue.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/sizeclasses.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/slice.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/string.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/stubs.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/stubs2.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/stubs3.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/stubs_linux.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/symtab.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/time.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/timestub.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/timestub2.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/trace.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/traceback_gccgo.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/type.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/typekind.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/unaligned1.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/utf8.go /export/gnu/import/git/sources/gcc/libgo/go/runtime/write_err.go runtime_sysinfo.go sigtab.go  -fPIC -o .libs/runtime.o
/export/gnu/import/git/sources/gcc/libgo/go/runtime/malloc.go:309:44: error: integer constant overflow
309 |  arenaBaseOffset uintptr = sys.GoarchAmd64 * (1 << 47)
    |                                            ^
make[9]: *** [Makefile:2964: runtime.lo] Error 1