utf8.c: Further simplify complex conditional

This splits these into an if clause, and an else clause

Author: khwilliamson

utf8.c

@@ -1601,16 +1601,11 @@ Perl__utf8n_to_uvchr_msgs_helper(const U8 *s,
                      * the overflow handling code */
         && LIKELY(! (possible_problems & UTF8_GOT_OVERFLOW)))
     {
-                                /* uv is valid for overlongs */
-        if (   (      LIKELY(! (possible_problems & ~UTF8_GOT_LONG))
-                   && isUNICODE_POSSIBLY_PROBLEMATIC(uv))
-            || (   UNLIKELY(possible_problems)
-                && (   isUTF8_POSSIBLY_PROBLEMATIC(*adjusted_s0)
-                    || UNLIKELY(UTF8_IS_PERL_EXTENDED(s0)))))
-        {
         /* If there were no malformations, or the only malformation is an
          * overlong, 'uv' is valid */
-        if (LIKELY(! (possible_problems & ~UTF8_GOT_LONG))) {
+        if (   LIKELY(! (possible_problems & ~UTF8_GOT_LONG))
+            && isUNICODE_POSSIBLY_PROBLEMATIC(uv))
+        {
             if (UNLIKELY(UNICODE_IS_SURROGATE(uv))) {
                 possible_problems |= UTF8_GOT_SURROGATE;
             }
@@ -1621,9 +1616,12 @@ Perl__utf8n_to_uvchr_msgs_helper(const U8 *s,
                 possible_problems |= UTF8_GOT_NONCHAR;
             }
         }
-        else {  /* Otherwise, need to look at the source UTF-8, possibly
-                   adjusted to be non-overlong */
-
+        else if (   UNLIKELY(possible_problems)
+                        /* Otherwise, need to look at the source UTF-8,
+                         * possibly adjusted to be non-overlong */
+                 && (   isUTF8_POSSIBLY_PROBLEMATIC(*adjusted_s0)
+                     || UNLIKELY(UTF8_IS_PERL_EXTENDED(s0))))
+        {
             if (UNLIKELY(NATIVE_UTF8_TO_I8(*adjusted_s0)
                                                     > UTF_START_BYTE_110000_))
             {
@@ -1645,7 +1643,6 @@ Perl__utf8n_to_uvchr_msgs_helper(const U8 *s,
             /* We need a complete well-formed UTF-8 character to discern
              * non-characters, so can't look for them here */
         }
-        }
     }
 
   ready_to_handle_errors: