diff --git a/util/psnr.cc b/util/psnr.cc
index fbcb4e453..52b04bd51 100644
--- a/util/psnr.cc
+++ b/util/psnr.cc
@@ -87,7 +87,7 @@ static uint32 SumSquareError_NEON(const uint8* src_a,
   "1:                                          \n"
     "ld1        {v0.16b}, [%0], #16            \n"
     "ld1        {v1.16b}, [%1], #16            \n"
-    "subs       %2, %2, #16                    \n"
+    "subs       %w2, %w2, #16                  \n"
     "usubl      v2.8h, v0.8b, v1.8b            \n"
     "usubl2     v3.8h, v0.16b, v1.16b          \n"
     "smlal      v16.4s, v2.4h, v2.4h           \n"