lib/mpi: avoid assembler warning

A wrapper around the umull assembly instruction might reuse
the input register as an output, which is undefined on
some ARM machines, as pointed out by this assembler warning:

  CC      lib/mpi/generic_mpih-mul1.o
/tmp/ccxJuxIy.s: Assembler messages:
/tmp/ccxJuxIy.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul2.o
/tmp/ccI0scAD.s: Assembler messages:
/tmp/ccI0scAD.s:53: rdhi, rdlo and rm must all be different
  CC      lib/mpi/generic_mpih-mul3.o
/tmp/ccMvVQcp.s: Assembler messages:
/tmp/ccMvVQcp.s:53: rdhi, rdlo and rm must all be different

This changes the constraints to force different registers to
be used as output.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/lib/mpi/longlong.h b/lib/mpi/longlong.h
index b90e255c2a680c20bccf2b7f4a9972af250cbd32..93336502af089685ce1f6ccbdb159003f1442d70 100644 (file)
--- a/lib/mpi/longlong.h
+++ b/lib/mpi/longlong.h
@@ -216,7 +216,7 @@ extern UDItype __udiv_qrnnd(UDItype *, UDItype, UDItype, UDItype);
        __asm__ ("%@ Inlined umul_ppmm\n" \
                "umull %r1, %r0, %r2, %r3" \
        : "=&r" ((USItype)(xh)), \
-                       "=r" ((USItype)(xl)) \
+                       "=&r" ((USItype)(xl)) \
        : "r" ((USItype)(a)), \
                        "r" ((USItype)(b)) \
        : "r0", "r1")