uvoffuni_to_utf8_flags_msgs: Avoid extra conditionals

The previous commit for EBCDIC paved the way for moving some checks for
a code point being for Perl extended UTF-8 out of places where they
cannot succeed.  The resultant simplifications more than compensate for
the two extra case statements added by this commit.

3 files changed, 46 insertions, 27 deletions

diff --git a/embed.fnc b/embed.fnc
index f087c54a7c..329d145449 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -2593,7 +2593,7 @@ Adm	|U8*	|uvchr_to_utf8	|NN U8 *d|UV uv
 Cp	|U8*	|uvuni_to_utf8	|NN U8 *d|UV uv
 Adm	|U8*	|uvchr_to_utf8_flags	|NN U8 *d|UV uv|UV flags
 Adm	|U8*	|uvchr_to_utf8_flags_msgs|NN U8 *d|UV uv|UV flags|NULLOK HV ** msgs
-CMpd	|U8*	|uvoffuni_to_utf8_flags	|NN U8 *d|UV uv|const UV flags
+CMpd	|U8*	|uvoffuni_to_utf8_flags	|NN U8 *d|UV uv|UV flags
 Cp	|U8*	|uvoffuni_to_utf8_flags_msgs|NN U8 *d|UV input_uv|const UV flags|NULLOK HV** msgs
 CdpbD	|U8*	|uvuni_to_utf8_flags	|NN U8 *d|UV uv|UV flags
 Apd	|char*	|pv_uni_display	|NN SV *dsv|NN const U8 *spv|STRLEN len|STRLEN pvlim|UV flags
diff --git a/proto.h b/proto.h
index deb7aa8ba6..b1c02121ee 100644
--- a/proto.h
+++ b/proto.h
@@ -4092,7 +4092,7 @@ PERL_CALLCONV void	Perl_utilize(pTHX_ int aver, I32 floor, OP* version, OP* idop
 #define PERL_ARGS_ASSERT_UVCHR_TO_UTF8_FLAGS
 /* PERL_CALLCONV U8*	uvchr_to_utf8_flags_msgs(pTHX_ U8 *d, UV uv, UV flags, HV ** msgs); */
 #define PERL_ARGS_ASSERT_UVCHR_TO_UTF8_FLAGS_MSGS
-PERL_CALLCONV U8*	Perl_uvoffuni_to_utf8_flags(pTHX_ U8 *d, UV uv, const UV flags);
+PERL_CALLCONV U8*	Perl_uvoffuni_to_utf8_flags(pTHX_ U8 *d, UV uv, UV flags);
 #define PERL_ARGS_ASSERT_UVOFFUNI_TO_UTF8_FLAGS	\
 	assert(d)
 PERL_CALLCONV U8*	Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 *d, UV input_uv, const UV flags, HV** msgs);
diff --git a/utf8.c b/utf8.c
index ff98fbe096..ea141d8479 100644
--- a/utf8.c
+++ b/utf8.c
@@ -260,7 +260,7 @@ The caller, of course, is responsible for freeing any returned HV.
 /* Undocumented; we don't want people using this.  Instead they should use
  * uvchr_to_utf8_flags_msgs() */
 U8 *
-Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 *d, UV input_uv, const UV flags, HV** msgs)
+Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 *d, UV input_uv, UV flags, HV** msgs)
 {
     U8 *p;
     UV shifted_uv = input_uv;
@@ -284,44 +284,63 @@ Perl_uvoffuni_to_utf8_flags_msgs(pTHX_ U8 *d, UV input_uv, const UV flags, HV**
             Perl_croak(aTHX_ "%s", form_cp_too_large_msg(16, NULL, 0, input_uv));
         }
 
+        if ((flags & (UNICODE_WARN_PERL_EXTENDED|UNICODE_WARN_SUPER))) {
+            U32 category = packWARN2(WARN_NON_UNICODE, WARN_PORTABLE);
+            const char * format = PL_extended_cp_format;
+            if (msgs) {
+                *msgs = new_msg_hv(Perl_form(aTHX_ format, input_uv),
+                                   category,
+                                   UNICODE_GOT_PERL_EXTENDED);
+            }
+            else {
+                Perl_ck_warner_d(aTHX_ category, format, input_uv);
+            }
+
+            /* Don't output a 2nd msg */
+            flags &= ~UNICODE_WARN_SUPER;
+        }
+
+        if (flags & UNICODE_DISALLOW_PERL_EXTENDED) {
+            return NULL;
+        }
+
         p = d + utf8_skip - 1;
-        while (p >= d + 4 + ONE_IF_EBCDIC_ZERO_IF_NOT) {
+        while (p >= d + 6 + ONE_IF_EBCDIC_ZERO_IF_NOT) {
             *p-- = I8_TO_NATIVE_UTF8((shifted_uv & MASK) | MARK);
             shifted_uv >>= SHIFT;
         }
 
         /* FALLTHROUGH */
 
+      case 6 + ONE_IF_EBCDIC_ZERO_IF_NOT:
+        d[5 + ONE_IF_EBCDIC_ZERO_IF_NOT]
+                                = I8_TO_NATIVE_UTF8((shifted_uv & MASK) | MARK);
+        shifted_uv >>= SHIFT;
+        /* FALLTHROUGH */
+
+      case 5 + ONE_IF_EBCDIC_ZERO_IF_NOT:
+        d[4 + ONE_IF_EBCDIC_ZERO_IF_NOT]
+                                = I8_TO_NATIVE_UTF8((shifted_uv & MASK) | MARK);
+        shifted_uv >>= SHIFT;
+        /* FALLTHROUGH */
+
       case 4 + ONE_IF_EBCDIC_ZERO_IF_NOT:
         if (UNLIKELY(UNICODE_IS_SUPER(input_uv))) {
-            if (       (flags & UNICODE_WARN_SUPER)
-                || (   (flags & UNICODE_WARN_PERL_EXTENDED)
-                    && UNICODE_IS_PERL_EXTENDED(input_uv)))
-            {
-                const char * format = super_cp_format;
+            if (flags & UNICODE_WARN_SUPER) {
                 U32 category = packWARN(WARN_NON_UNICODE);
-                U32 flag = UNICODE_GOT_SUPER;
-
-                /* Choose the more dire applicable warning */
-                if (UNICODE_IS_PERL_EXTENDED(input_uv)) {
-                    format = PL_extended_cp_format;
-                    category = packWARN2(WARN_NON_UNICODE, WARN_PORTABLE);
-                    if (flags & (UNICODE_WARN_PERL_EXTENDED
-                                |UNICODE_DISALLOW_PERL_EXTENDED))
-                    {
-                        flag = UNICODE_GOT_PERL_EXTENDED;
-                    }
-                }
+                const char * format = super_cp_format;
 
                 if (msgs) {
                     *msgs = new_msg_hv(Perl_form(aTHX_ format, input_uv),
-                                    category, flag);
+                                       category,
+                                       UNICODE_GOT_SUPER);
                 }
-                else if (    ckWARN_d(WARN_NON_UNICODE)
-                        || (   (flag & UNICODE_GOT_PERL_EXTENDED)
-                            && ckWARN(WARN_PORTABLE)))
-                {
-                    Perl_warner(aTHX_ category, format, input_uv);
+                else {
+                    Perl_ck_warner_d(aTHX_ category, format, input_uv);
+                }
+
+                if (flags & UNICODE_DISALLOW_SUPER) {
+                    return NULL;
                 }
             }
             if (       (flags & UNICODE_DISALLOW_SUPER)