Stop minlen regexp optimisation from rejecting long strings

This fixes #112790 and part of #116907.

The length of the string is cast to I32, so it wraps and end up less
than the minimum length.

For now, simply skip this optimisation if minlen itself wraps and
becomes negative.

1 files changed, 22 insertions, 0 deletions

diff --git a/t/bigmem/regexp.t b/t/bigmem/regexp.t
new file mode 100644
index 0000000000..ef029fbd9b
--- /dev/null
+++ b/t/bigmem/regexp.t
@@ -0,0 +1,22 @@
+#!perl
+BEGIN {
+    chdir 't';
+    unshift @INC, "../lib";
+    require './test.pl';
+}
+
+use Config qw(%Config);
+
+$ENV{PERL_TEST_MEMORY} >= 2
+    or skip_all("Need ~2Gb for this test");
+$Config{ptrsize} >= 8
+    or skip_all("Need 64-bit pointers for this test");
+
+plan(2);
+
+# [perl #116907]
+# ${\2} to defeat constant folding, which in this case actually slows
+# things down
+my $x=" "x(${\2}**31);
+ok $x =~ /./, 'match against long string succeeded';
+is "$-[0]-$+[0]", '0-1', '@-/@+ after match against long string';