ubsan: undefined shift in sign_extend

[Alan Modra]

	* libhppa.h (sign_extend): Avoid undefined behaviour.

diff --git a/bfd/libhppa.h b/bfd/libhppa.h
index 1de2d5c943b..ebaffe66abf 100644
--- a/bfd/libhppa.h
+++ b/bfd/libhppa.h
@@ -162,7 +162,7 @@ enum hppa_reloc_expr_type_alt
 static inline unsigned ATTRIBUTE_UNUSED
 sign_extend (unsigned x, unsigned len)
 {
-  unsigned signbit = (1 << (len - 1));
+  unsigned signbit = (1u << (len - 1));
   unsigned mask = (signbit << 1) - 1;
   return ((x & mask) ^ signbit) - signbit;
 }

-- 
Alan Modra
Australia Development Lab, IBM