*/
void
-Perl_sv_insert_flags(pTHX_ SV *const bigstr, const STRLEN offset, const STRLEN len, const char *const little, const STRLEN littlelen, const U32 flags)
+Perl_sv_insert_flags(pTHX_ SV *const bigstr, const STRLEN offset, const STRLEN len, const char *little, const STRLEN littlelen, const U32 flags)
{
char *big;
char *mid;
SvPV_force_flags(bigstr, curlen, flags);
(void)SvPOK_only_UTF8(bigstr);
+
+ if (little >= SvPVX(bigstr) &&
+ little < SvPVX(bigstr) + (SvLEN(bigstr) ? SvLEN(bigstr) : SvCUR(bigstr))) {
+ /* little is a pointer to within bigstr, since we can reallocate bigstr,
+ or little...little+littlelen might overlap offset...offset+len we make a copy
+ */
+ little = savepvn(little, littlelen);
+ SAVEFREEPV(little);
+ }
+
if (offset + len > curlen) {
SvGROW(bigstr, offset+len+1);
Zero(SvPVX(bigstr)+curlen, offset+len-curlen, char);