https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92002
--- Comment #9 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot
Uni-Bielefeld.DE> ---
> --- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
> Did this somehow get fixed (the bootstrap?) or require some nonstandard
> configuration?
Not at all. I still cannot make any sense of the warning, but hacked
around it by disabling -Werror for the affected files in t-sparc to get
any work done:
diff --git a/gcc/config/sparc/t-sparc b/gcc/config/sparc/t-sparc
--- a/gcc/config/sparc/t-sparc
+++ b/gcc/config/sparc/t-sparc
@@ -27,3 +27,7 @@ sparc-c.o: $(srcdir)/config/sparc/sparc-
sparc-d.o: $(srcdir)/config/sparc/sparc-d.c
$(COMPILE) $<
$(POSTCOMPILE)
+
+# Hack around PR bootstrap/92002.
+tree-ssanames.o-warn += -Wno-error
+wide-int.o-warn += -Wno-error
