vim-patch:9.0.0951: trying every character position for a match is inefficient (#21198)

Problem:    Trying every character position for a match is inefficient.
Solution:   Use the start position of the match ignoring "\zs".

https://github.com/vim/vim/commit/01105b37a108022515d364201767f7f111ec4222

Co-authored-by: Bram Moolenaar <Bram@vim.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/src/nvim/regexp_bt.c b/src/nvim/regexp_bt.c
index 2337dbb51c..9411d17f57 100644
--- a/src/nvim/regexp_bt.c
+++ b/src/nvim/regexp_bt.c
@@ -4930,15 +4930,16 @@ static long regtry(bt_regprog_T *prog, colnr_T col, proftime_T *tm, int *timed_o
 /// Match a regexp against a string ("line" points to the string) or multiple
 /// lines (if "line" is NULL, use reg_getline()).
 ///
-/// @param col        column to start search
+/// @param startcol   column to start looking for match
 /// @param tm         timeout limit or NULL
 /// @param timed_out  flag set on timeout or NULL
 ///
 /// @return  0 for failure, or number of lines contained in the match.
-static long bt_regexec_both(char_u *line, colnr_T col, proftime_T *tm, int *timed_out)
+static long bt_regexec_both(char_u *line, colnr_T startcol, proftime_T *tm, int *timed_out)
 {
   bt_regprog_T *prog;
   char_u *s;
+  colnr_T col = startcol;
   long retval = 0L;
 
   // Create "regstack" and "backpos" if they are not allocated yet.
@@ -5113,10 +5114,18 @@ theend:
           || (end->lnum == start->lnum && end->col < start->col)) {
         rex.reg_mmatch->endpos[0] = rex.reg_mmatch->startpos[0];
       }
+
+      // startpos[0] may be set by "\zs", also return the column where
+      // the whole pattern matched.
+      rex.reg_mmatch->rmm_matchcol = col;
     } else {
       if (rex.reg_match->endp[0] < rex.reg_match->startp[0]) {
         rex.reg_match->endp[0] = rex.reg_match->startp[0];
       }
+
+      // startpos[0] may be set by "\zs", also return the column where
+      // the whole pattern matched.
+      rex.reg_match->rm_matchcol = col;
     }
   }