RE: [ID 20000729.003] segfault with (??{ qr/blah/ })

Looking at the Purify dump, I'd suspect the problem starts with the first
invalid pointer read:
    S_nextchar     [re_comp.c:3575]
    
        for (;;) {
        if (*PL_regcomp_parse == '(' && PL_regcomp_parse[1] == '?' &&
 =>         PL_regcomp_parse[2] == '#') {
            while (*PL_regcomp_parse && *PL_regcomp_parse != ')')
            PL_regcomp_parse++;
            PL_regcomp_parse++;
    S_reg          [re_comp.c:1791]
                FAIL("Eval-group in insecure regular expression");
            }
    
 =>         nextchar();
            if (logical) {
                ret = reg_node(LOGICAL);
                if (!SIZE_ONLY)
    S_regatom      [re_comp.c:2297]
        break;
        case '(':
        nextchar();
     =>     ret = reg(1, &flags);
            if (ret == NULL) {
                if (flags & TRYAGAIN)
                    goto tryagain;
    S_regpiece     [re_comp.c:2096]
            I32 min;
            I32 max = REG_INFTY;
        
     =>     ret = regatom(&flags);
            if (ret == NULL) {
            if (flags & TRYAGAIN)
                *flagp |= TRYAGAIN;
    S_regbranch    [re_comp.c:2044]
            nextchar();
            while (PL_regcomp_parse < PL_regxend && *PL_regcomp_parse != '|'
&& *PL_regcomp_parse != ')') {
            flags &= ~TRYAGAIN;
     =>     latest = regpiece(&flags);
            if (latest == NULL) {
                if (flags & TRYAGAIN)
                continue;
    S_reg          [re_comp.c:1902]
            ret = NULL;
        
            /* Pick up the branches, linking them together. */
     =>     br = regbranch(&flags, 1);
            if (br == NULL)
            return(NULL);
            if (*PL_regcomp_parse == '|') {
    my_regcomp     [re_comp.c:1415]
            PL_regcode->next_off = ((PL_seen_evals > U16_MAX) ? U16_MAX :
PL_seen_evals);
            REGC((U8)REG_MAGIC, (char*) PL_regcode++);
            r->data = 0;
     =>     if (reg(0, &flags) == NULL)
            return(NULL);
        
            /* Dig out information for optimizations. */

====================================================
Mark Leighton Fisher    Thomson Consumer Electronics
fisherm@tce.com         Indianapolis, IN, USA
"Display some adaptability."  -- Doug Shaftoe, _Cryptonomicon_

• [ID 20000729.003] segfault with (??{ qr/blah/ }) by Jeffrey Friedl
• RE: [ID 20000729.003] segfault with (??{ qr/blah/ }) by Fisher Mark