diff --git a/pngpriv.h b/pngpriv.h
index 54a64c497..f2f289f91 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -204,6 +204,8 @@
 #    else
 #       define PNG_MIPS_MMI_OPT 0
 #    endif
+#  else
+#    define PNG_MIPS_MMI_OPT 0
 #  endif
 #endif
 
@@ -215,6 +217,14 @@
 #  endif
 #endif
 
+#ifndef PNG_LOONGARCH_LSX_OPT
+#  if defined(__loongarch_sx)
+#     define PNG_LOONGARCH_LSX_OPT 1
+#  else
+#     define PNG_LOONGARCH_LSX_OPT 0
+#  endif
+#endif
+
 #ifndef PNG_INTEL_SSE_OPT
 #   ifdef PNG_INTEL_SSE
       /* Only check for SSE if the build configuration has been modified to