Fix backref iterators when PCRE2_MATCH_UNSET_BACKREF is set in JIT

ChangeLog

@@ -168,6 +168,8 @@ undefined behaviour.
 
 45. Fix \X matching in 32 bit mode without UTF in JIT.
 
+46. Fix backref iterators when PCRE2_MATCH_UNSET_BACKREF is set in JIT.
+
 
 Version 10.42 11-December-2022
 ------------------------------

src/pcre2_jit_compile.c

@@ -9539,9 +9539,11 @@ if (!minimize)
     if (ref)
       OP1(SLJIT_MOV, TMP1, 0, SLJIT_MEM1(SLJIT_SP), OVECTOR(offset));
     OP1(SLJIT_MOV, SLJIT_MEM1(STACK_TOP), STACK(0), SLJIT_IMM, 0);
+
     if (ref)
       {
-      add_jump(compiler, &backtrack->topbacktracks, CMP(SLJIT_EQUAL, TMP1, 0, SLJIT_MEM1(SLJIT_SP), OVECTOR(1)));
+      if (!common->unset_backref)
+        add_jump(compiler, &backtrack->topbacktracks, CMP(SLJIT_EQUAL, TMP1, 0, SLJIT_MEM1(SLJIT_SP), OVECTOR(1)));
       zerolength = CMP(SLJIT_EQUAL, TMP1, 0, SLJIT_MEM1(SLJIT_SP), OVECTOR(offset + 1));
       }
     else

src/pcre2_jit_test.c

@@ -595,6 +595,7 @@ static struct regression_test_case regression_test_cases[] = {
 	{ CMU | PCRE2_DUPNAMES, A, 0, 0, "(?:(?<A>AA)|(?<A>BB))\\k<A>{1,3}M", "aaaaaaaabbbbaabbbbm" },
 	{ CMU | PCRE2_DUPNAMES, A, 0, 0, "(?:(?<A>AA)|(?<A>BB))\\k<A>{0,3}?M", "aaaaaabbbbbbaabbbbbbbbbbm" },
 	{ CMU | PCRE2_DUPNAMES, A, 0, 0, "(?:(?<A>AA)|(?<A>BB))\\k<A>{2,3}?", "aaaabbbbaaaabbbbbbbbbb" },
+	{ MU | PCRE2_MATCH_UNSET_BACKREF, A, 0, 0, "(a)|\\1+c", "xxc" },
 
 	/* Assertions. */
 	{ MU, A, 0, 0, "(?=xx|yy|zz)\\w{4}", "abczzdefg" },