re_intuit_start(): eliminate one label

Currently the code looks like:

    if (rx_origin + start_shift >= check_at)
        goto retry_floating_check;

    ....

  retry_floating_check:
    rx_origin = check_at - start_shift;
    goto hop_and_restart;

But that conditional only kicks in when the floating substring (which was
the check substring) matched, so this condition always applies:

    rx_origin + start_shift <= check_at

So the condition in the code will only ever be true when

    rx_origin + start_shift == check_at

In this case, this assignment is a noop:

    rx_origin = check_at - start_shift;

So skip it and jump directly to hop_and_restart. This eliminates the
retry_floating_check: label.

1 files changed, 4 insertions, 3 deletions

diff --git a/regexec.c b/regexec.c
index 5d70686592..73bd53232d 100644
--- a/regexec.c
+++ b/regexec.c
@@ -1296,8 +1296,10 @@ Perl_re_intuit_start(pTHX_
 		    goto restart;
 		}
 		/* Have both, check_string is floating */
-		if (rx_origin + start_shift >= check_at) /* Contradicts floating=check */
-		    goto retry_floating_check;
+		assert(rx_origin + start_shift <= check_at);
+		if (rx_origin + start_shift == check_at)
+                    /* already at latest position float substr could match */
+		    goto hop_and_restart;
 		/* Recheck anchored substring, but not floating... */
 		if (!check) {
                     rx_origin = NULL;
@@ -1327,7 +1329,6 @@ Perl_re_intuit_start(pTHX_
 	    if (!(utf8_target ? prog->float_utf8 : prog->float_substr))	/* Could have been deleted */
 		goto fail;
 	    /* Check is floating substring. */
-	  retry_floating_check:
 	    rx_origin = check_at - start_shift;
 	    goto hop_and_restart;
 	}