tree 2500a228ef908d362461e7d9062ca62ee0f59485
parent 6c109e908aa4006c0cd147d2397023b7b8f2705d
author Paul Wankadia <junyer@google.com> 1580529089 -0800
committer Paul Wankadia <junyer@google.com> 1580529644 +0000

Avoid using the forward DFA in "ANCHOR_END" cases.

In UNANCHORED cases where the regexp is anchored explicitly at the end
only, we don't need the forward DFA because we already know where the
match must end! Instead, the reverse DFA can say whether there is a
match and (optionally) where it starts.

Change-Id: I52ee19626863d06b9c52dc107eb46c3ba9eabf63
Reviewed-on: https://code-review.googlesource.com/c/re2/+/51290
Reviewed-by: Paul Wankadia <junyer@google.com>