From: Gerd Möllmann <gerd.moellmann@gmail.com>
Date: Tue, 22 Apr 2025 09:35:12 +0000 (+0200)
Subject: Realloc less often in adjust_glyph_matrix (bug#77961)
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=3330c9979afdf9700b6220508b5f1372fa14bde2;p=emacs.git

Realloc less often in adjust_glyph_matrix (bug#77961)

* src/dispnew.c (adjust_glyph_matrix): Only xnrealloc when the
glyph matrix got wider or taller.

(cherry picked from commit 871ec9615a949e967bf7d19466eb9c56ed80ff7e)
---

diff --git a/src/dispnew.c b/src/dispnew.c
index ff14efe0c4a..9257bb71774 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -503,13 +503,17 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
 
 	  while (row < end)
 	    {
-	      row->glyphs[LEFT_MARGIN_AREA]
-		= xnrealloc (row->glyphs[LEFT_MARGIN_AREA],
-			     dim.width, sizeof (struct glyph));
-	      /* We actually need to clear only the 'frame' member, but
-                 it's easier to clear everything.  */
-	      memset (row->glyphs[LEFT_MARGIN_AREA], 0,
-		      dim.width * sizeof (struct glyph));
+	      /* Only realloc if matrix got wider or taller (bug#77961).  */
+	      if (dim.width > matrix->matrix_w || new_rows)
+		{
+		  row->glyphs[LEFT_MARGIN_AREA]
+		    = xnrealloc (row->glyphs[LEFT_MARGIN_AREA],
+				 dim.width, sizeof (struct glyph));
+		  /* We actually need to clear only the 'frame' member, but
+		     it's easier to clear everything.  */
+		  memset (row->glyphs[LEFT_MARGIN_AREA], 0,
+			  dim.width * sizeof (struct glyph));
+		}
 
 	      if ((row == matrix->rows + dim.height - 1
 		   /* The mode line, if displayed, never has marginal