regen/mk_invlists.pl: Skip unnecessary work

This reorders the code points below 256 depending on the platform.
However all platforms have the same values for those above 255, so can
skip this code if the first code point (and hence all code points) being
output isn't one of those affected.

1 files changed, 9 insertions, 0 deletions

diff --git a/regen/mk_invlists.pl b/regen/mk_invlists.pl
index 5d15690a1c..4902f6e1c5 100644
--- a/regen/mk_invlists.pl
+++ b/regen/mk_invlists.pl
@@ -230,6 +230,14 @@ for my $charset (get_supported_code_pages()) {
             @invlist = prop_invlist($lookup_prop, '_perl_core_internal_ok');
         }
         die "Could not find inversion list for '$lookup_prop'" unless @invlist;
+
+        # Re-order the Unicode code points to native ones for this platform;
+        # only needed for code points below 256, and only if the first range
+        # doesn't span the whole of 0..256 (256 not 255 because a re-ordering
+        # could cause 256 to need to be in the same range as 255.)
+        if (! $nonl1_only || ($invlist[0] < 256
+                              && ! ($invlist[0] == 0 && $invlist[1] > 256)))
+        {
         my @full_list;
         for (my $i = 0; $i < @invlist; $i += 2) {
             my $upper = ($i + 1) < @invlist
@@ -250,6 +258,7 @@ for my $charset (get_supported_code_pages()) {
         }
         @full_list = sort { $a <=> $b } @full_list;
         @invlist = mk_invlist_from_cp_list(\@full_list);
+        }
 
         if ($l1_only) {
             for my $i (0 .. @invlist - 1 - 1) {