Does a TRIE-EXACT only pattern do unnecessary work? #23864
Description
Description
If you run: perl -e 'use re q|debug|; my $x = "x" x 10; 1 while $x =~ /xx|ab/aag;',
the pattern has compiled to a TRIE-EXACT node:
Compiling REx "xx|ab"
Final program:
1: TRIE-EXACT[ax] (9)
<xx>
<ab>
9: END (0)
The output for each match is something like:
stclass AHOCORASICK-EXACT[ax] minlen 2
Matching REx "xx|ab" against "xxxxxxxxxx"
Matching stclass AHOCORASICK-EXACT[ax] against "xxxxxxxxxx" (10 bytes)
0 <> <xxxxxxxxxx> | 0| Charid: 1 CP: 78 State: 1, word=0 - legal
1 <x> <xxxxxxxxx> | 0| Charid: 1 CP: 78 State: 2, word=0 - legal
2 <xx> <xxxxxxxx> | 0| Charid: 1 CP: 78 State: 3, word=1 - accepting
Matches word #1 at position 0. Trying full pattern...
0 <> <xxxxxxxxxx> | 0| 1:TRIE-EXACT[ax](9)
0 <> <xxxxxxxxxx> | 0| TRIE: State: 1 Accepted: N TRIE: Charid: 1 CP: 78 After State: 2
1 <x> <xxxxxxxxx> | 0| TRIE: State: 2 Accepted: N TRIE: Charid: 1 CP: 78 After State: 3
2 <xx> <xxxxxxxx> | 0| TRIE: State: 3 Accepted: Y TRIE: Charid: 0 CP: 0 After State: 0
| 0| TRIE: got 1 possible matches
| 0| TRIE matched word #1, continuing
| 0| TRIE: only one match left, short-circuiting: #1 <xx>
2 <xx> <xxxxxxxx> | 0| 9:END(0)
Match successful!
Is it necessary to try the full TRIE-EXACT pattern when in effect, AHOCORASICK-EXACT[ax] has already found a whole pattern match?
Perl configuration
blead