regex.c (mutually_exclusive_aux) <wordbound>: Remove optimization

Another case that was too optimistic.  Better use \> or \< rather
than \b if you want your regexp to be handled efficiently.

* src/regex-emacs.c (mutually_exclusive_aux) <wordbound>: Cancel optimization.
* test/src/regex-emacs-tests.el (regexp-tests-backtrack-optimization):
New test.

1 files changed, 1 insertions, 0 deletions

diff --git a/test/src/regex-emacs-tests.el b/test/src/regex-emacs-tests.el
index d78f70ba409..621e4dbe2c0 100644
--- a/test/src/regex-emacs-tests.el
+++ b/test/src/regex-emacs-tests.el
@@ -907,6 +907,7 @@ This evaluates the TESTS test cases from glibc."
     ;; Regression check for overly optimistic optimization.
     (should (eq 0 (string-match "\\(ca*\\|ab\\)+d" "cabd")))
     (should (string-match "\\(aa*\\|b\\)*c" "ababc"))
+    (should (string-match " \\sw*\\bfoo" " foo"))
     ))
 
 (ert-deftest regexp-tests-zero-width-assertion-repetition ()