diff --git a/ChangeLog b/ChangeLog
index 2edaed6..a7d18a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,9 @@ error. This bug was discovered by the LLVM fuzzer.
 
 4. Implemented pcre2_callout_enumerate().
 
+5. Fix JIT compilation of conditional blocks whose assertion
+   is converted to (*FAIL). E.g: /(?(?!))/.
+
 
 Version 10.10 06-March-2015
 ---------------------------
diff --git a/src/pcre2_jit_compile.c b/src/pcre2_jit_compile.c
index 8578891..f23c136 100644
--- a/src/pcre2_jit_compile.c
+++ b/src/pcre2_jit_compile.c
@@ -7044,7 +7044,7 @@ if (SLJIT_UNLIKELY(opcode == OP_COND || opcode == OP_SCOND))
   {
   SLJIT_COMPILE_ASSERT(OP_DNRREF == OP_RREF + 1 && OP_FALSE == OP_RREF + 2 && OP_TRUE == OP_RREF + 3,
     compile_time_checks_must_be_grouped_together);
-  has_alternatives = (*matchingpath >= OP_RREF && *matchingpath <= OP_TRUE) ? FALSE : TRUE;
+  has_alternatives = ((*matchingpath >= OP_RREF && *matchingpath <= OP_TRUE) || *matchingpath == OP_FAIL) ? FALSE : TRUE;
   }
 
 if (SLJIT_UNLIKELY(opcode == OP_COND) && (*cc == OP_KETRMAX || *cc == OP_KETRMIN))
@@ -7303,7 +7303,7 @@ if (opcode == OP_COND || opcode == OP_SCOND)
     add_jump(compiler, &(BACKTRACK_AS(bracket_backtrack)->u.condfailed), JUMP(SLJIT_ZERO));
     matchingpath += 1 + 2 * IMM2_SIZE;
     }
-  else if (*matchingpath >= OP_RREF && *matchingpath <= OP_TRUE)
+  else if ((*matchingpath >= OP_RREF && *matchingpath <= OP_TRUE) || *matchingpath == OP_FAIL)
     {
     /* Never has other case. */
     BACKTRACK_AS(bracket_backtrack)->u.condfailed = NULL;
@@ -7314,7 +7314,7 @@ if (opcode == OP_COND || opcode == OP_SCOND)
       stacksize = 1;
       matchingpath++;
       }
-    else if (*matchingpath == OP_FALSE)
+    else if (*matchingpath == OP_FALSE || *matchingpath == OP_FAIL)
       stacksize = 0;
     else if (*matchingpath == OP_RREF)
       {
diff --git a/src/pcre2_jit_test.c b/src/pcre2_jit_test.c
index ad74013..b076c67 100644
--- a/src/pcre2_jit_test.c
+++ b/src/pcre2_jit_test.c
@@ -647,6 +647,9 @@ static struct regression_test_case regression_test_cases[] = {
 	{ MU, A, 0, 0, "(?P<Name>a)?(?P<Name2>b)?(?(Name)c|d)+?dd", "bcabcacdb bdddd" },
 	{ MU, A, 0, 0, "(?P<Name>a)?(?P<Name2>b)?(?(Name)c|d)+l", "ababccddabdbccd abcccl" },
 	{ MU, A, 0, 0, "((?:a|aa)(?(1)aaa))x", "aax" },
+	{ MU, A, 0, 0, "(?(?!)a|b)", "ab" },
+	{ MU, A, 0, 0, "(?(?!)a)", "ab" },
+	{ MU, A, 0, 0 | F_NOMATCH, "(?(?!)a|b)", "ac" },
 
 	/* Set start of match. */
 	{ MU, A, 0, 0, "(?:\\Ka)*aaaab", "aaaaaaaa aaaaaaabb" },