https://bugs.gentoo.org/170146
http://gcc.gnu.org/ml/gcc-patches/2009-11/msg00403.html
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=223888

alpha: turn -mcpu=<cpu> into -m<cpu> for assembler all the time

--- a/gcc/config/alpha/elf.h
+++ b/gcc/config/alpha/elf.h
@@ -46,7 +46,7 @@ along with GCC; see the file COPYING3.  If not see
 #define CC1_SPEC  "%{G*}"
 
 #undef  ASM_SPEC
-#define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug}"
+#define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug} %{mcpu=*:-m%*}"
 
 #undef  IDENT_ASM_OP
 #define IDENT_ASM_OP "\t.ident\t"