Retract #14985, #14899, and #14990, following the principles

"Do no harm." and "If it ain't broke, don't fix it."

Firstly, the #14985 broke badly on UTF-EBCDIC, #14990 fixed
some, but still broken, and I do not have the extra brain
cells for the EBCDIC backport.  Secondly, the old version
worked both in EBCDIC and non-.  Thirdly, the old version
may be more amenable for the behaviour suggsted by Anton
Tagunov regarding the encoding pragma.

p4raw-id: //depot/perl@15084

1 files changed, 59 insertions, 22 deletions

diff --git a/sv.c b/sv.c
index f893fa6bd8..27150d6706 100644
--- a/sv.c
+++ b/sv.c
@@ -5349,6 +5349,7 @@ Perl_sv_eq(pTHX_ register SV *sv1, register SV *sv2)
     char *pv2;
     STRLEN cur2;
     I32  eq     = 0;
+    char *tpv   = Nullch;
 
     if (!sv1) {
 	pv1 = "";
@@ -5364,13 +5365,35 @@ Perl_sv_eq(pTHX_ register SV *sv1, register SV *sv2)
     else
 	pv2 = SvPV(sv2, cur2);
 
-    if (SvUTF8(sv1) == SvUTF8(sv2) || IN_BYTES)
-	eq = (cur1 == cur2) && memEQ(pv1, pv2, cur1);
-    else if (SvUTF8(sv1)) /* do not utf8ize the comparands as a side-effect */
-	eq = !memcmp_byte_utf8(pv2, cur2, pv1, cur1);
-    else
-	eq = !memcmp_byte_utf8(pv1, cur1, pv2, cur2);
+    /* do not utf8ize the comparands as a side-effect */
+    if (cur1 && cur2 && SvUTF8(sv1) != SvUTF8(sv2) && !IN_BYTES) {
+	bool is_utf8 = TRUE;
+        /* UTF-8ness differs */
+
+	if (SvUTF8(sv1)) {
+	    /* sv1 is the UTF-8 one , If is equal it must be downgrade-able */
+	    char *pv = (char*)bytes_from_utf8((U8*)pv1, &cur1, &is_utf8);
+	    if (pv != pv1)
+		pv1 = tpv = pv;
+	}
+	else {
+	    /* sv2 is the UTF-8 one , If is equal it must be downgrade-able */
+	    char *pv = (char *)bytes_from_utf8((U8*)pv2, &cur2, &is_utf8);
+	    if (pv != pv2)
+		pv2 = tpv = pv;
+	}
+	if (is_utf8) {
+	    /* Downgrade not possible - cannot be eq */
+	    return FALSE;
+	}
+    }
+
+    if (cur1 == cur2)
+	eq = memEQ(pv1, pv2, cur1);
 	
+    if (tpv != Nullch)
+	Safefree(tpv);
+
     return eq;
 }
 
@@ -5390,7 +5413,9 @@ Perl_sv_cmp(pTHX_ register SV *sv1, register SV *sv2)
 {
     STRLEN cur1, cur2;
     char *pv1, *pv2;
-    I32  retval;
+    I32  cmp;
+    bool pv1tmp = FALSE;
+    bool pv2tmp = FALSE;
 
     if (!sv1) {
 	pv1 = "";
@@ -5406,28 +5431,40 @@ Perl_sv_cmp(pTHX_ register SV *sv1, register SV *sv2)
     else
 	pv2 = SvPV(sv2, cur2);
 
+    /* do not utf8ize the comparands as a side-effect */
+    if (cur1 && cur2 && SvUTF8(sv1) != SvUTF8(sv2) && !IN_BYTES) {
+	if (SvUTF8(sv1)) {
+	    pv2 = (char*)bytes_to_utf8((U8*)pv2, &cur2);
+	    pv2tmp = TRUE;
+	}
+	else {
+	    pv1 = (char*)bytes_to_utf8((U8*)pv1, &cur1);
+	    pv1tmp = TRUE;
+	}
+    }
+
     if (!cur1) {
-	return cur2 ? -1 : 0;
+	cmp = cur2 ? -1 : 0;
     } else if (!cur2) {
-	return 1;
-    } else if (SvUTF8(sv1) == SvUTF8(sv2) || IN_BYTES) {
-	retval = memcmp((void*)pv1, (void*)pv2, cur1 < cur2 ? cur1 : cur2);
+	cmp = 1;
+    } else {
+	I32 retval = memcmp((void*)pv1, (void*)pv2, cur1 < cur2 ? cur1 : cur2);
 
 	if (retval) {
-	    return retval < 0 ? -1 : 1;
+	    cmp = retval < 0 ? -1 : 1;
 	} else if (cur1 == cur2) {
-	    return 0;
-	} else {
-	    return cur1 < cur2 ? -1 : 1;
+	    cmp = 0;
+        } else {
+	    cmp = cur1 < cur2 ? -1 : 1;
 	}
-    } else if (SvUTF8(sv1)) /* do not utf8ize the comparands as a side-effect */
-	retval = -memcmp_byte_utf8(pv2, cur2, pv1, cur1);
-    else
-	retval = memcmp_byte_utf8(pv1, cur1, pv2, cur2);
+    }
 
-    if (retval)				/* CURs taken into account already */
-	return retval < 0 ? -1 : 1;
-    return 0;
+    if (pv1tmp)
+	Safefree(pv1);
+    if (pv2tmp)
+	Safefree(pv2);
+
+    return cmp;
 }
 
 /*