Yet another attempt at JIT code

Author: NWilson

src/pcre2_jit_compile.c

@@ -13779,29 +13779,22 @@ lookbehind). */
 if (common->has_set_som &&
     (common->re->extra_options & PCRE2_EXTRA_ALLOW_LOOKAROUND_BSK) == 0)
   {
-  struct sljit_jump *do_return;
-  struct sljit_jump *fallthrough;
-
   if (HAS_VIRTUAL_REGISTERS)
     {
-    OP1(SLJIT_MOV, TMP1, 0, ARGUMENTS, 0);
-    OP1(SLJIT_MOV, TMP1, 0, SLJIT_MEM1(TMP1), SLJIT_OFFSETOF(jit_arguments, str));
+    OP1(SLJIT_MOV, TMP2, 0, ARGUMENTS, 0);
+    OP1(SLJIT_MOV, TMP2, 0, SLJIT_MEM1(TMP2), SLJIT_OFFSETOF(jit_arguments, str));
     }
   else
     {
-    OP1(SLJIT_MOV, TMP1, 0, SLJIT_MEM1(ARGUMENTS), SLJIT_OFFSETOF(jit_arguments, str));
+    OP1(SLJIT_MOV, TMP2, 0, SLJIT_MEM1(ARGUMENTS), SLJIT_OFFSETOF(jit_arguments, str));
     }
+  OP1(SLJIT_MOV, TMP3, 0, SLJIT_MEM1(SLJIT_SP), OVECTOR(0));
 
-  /* (ovector[0] < jit_arguments->str)? */
-  do_return = CMP(SLJIT_LESS, SLJIT_MEM1(SLJIT_SP), OVECTOR(0), TMP1, 0);
-  /* (ovector[0] <= STR_PTR)?  NB. ovector[1] hasn't yet been set to STR_PTR. */
-  fallthrough = CMP(SLJIT_LESS_EQUAL, SLJIT_MEM1(SLJIT_SP), OVECTOR(0), STR_PTR, 0);
-
-  JUMPHERE(do_return);
   OP1(SLJIT_MOV, SLJIT_RETURN_REG, 0, SLJIT_IMM, PCRE2_ERROR_BAD_BACKSLASH_K);
-  add_jump(compiler, &common->abort, JUMP(SLJIT_JUMP));
-
-  JUMPHERE(fallthrough);
+  /* (ovector[0] < jit_arguments->str)? */
+  add_jump(compiler, &common->abort, CMP(SLJIT_LESS, TMP3, 0, TMP2, 0));
+  /* (ovector[0] > STR_PTR)?  NB. ovector[1] hasn't yet been set to STR_PTR. */
+  add_jump(compiler, &common->abort, CMP(SLJIT_GREATER, TMP3, 0, STR_PTR, 0));
   }
 
 /* This means we have a match. Update the ovector. */