diff -up diffutils-3.3/lib/diffseq.h.me diffutils-3.3/lib/diffseq.h

--- diffutils-3.3/lib/diffseq.h.me	2018-08-10 14:26:48.940444056 +0200

+++ diffutils-3.3/lib/diffseq.h	2018-08-10 14:26:50.453439777 +0200

@@ -138,12 +132,6 @@ struct partition

   /* Midpoints of this partition.  */

   OFFSET xmid;

   OFFSET ymid;

-

-  /* True if low half will be analyzed minimally.  */

-  bool lo_minimal;

-

-  /* Likewise for high half.  */

-  bool hi_minimal;

 };

@@ -175,7 +156,7 @@ struct partition

    suboptimal diff output.  It cannot cause incorrect diff output.  */

 static void

-diag (OFFSET xoff, OFFSET xlim, OFFSET yoff, OFFSET ylim, bool find_minimal,

+diag (OFFSET xoff, OFFSET xlim, OFFSET yoff, OFFSET ylim,

       struct partition *part, struct context *ctxt)

 {

   OFFSET *const fd = ctxt->fdiag;       /* Give the compiler a chance. */

@@ -235,7 +216,6 @@ diag (OFFSET xoff, OFFSET xlim, OFFSET y

             {

               part->xmid = x;

               part->ymid = y;

-              part->lo_minimal = part->hi_minimal = true;

               return;

             }

         }

@@ -268,14 +248,10 @@ diag (OFFSET xoff, OFFSET xlim, OFFSET y

             {

               part->xmid = x;

               part->ymid = y;

-              part->lo_minimal = part->hi_minimal = true;

               return;

             }

         }

-      if (find_minimal)

-        continue;

-

 #ifdef USE_HEURISTIC

       /* Heuristic: check occasionally for a diagonal that has made lots

          of progress compared with the edit distance.  If we have any

@@ -319,11 +295,7 @@ diag (OFFSET xoff, OFFSET xlim, OFFSET y

                   }

               }

             if (best > 0)

-              {

-                part->lo_minimal = true;

-                part->hi_minimal = false;

-                return;

-              }

+	      return;

           }

           {

@@ -358,77 +330,10 @@ diag (OFFSET xoff, OFFSET xlim, OFFSET y

                   }

               }

             if (best > 0)

-              {

-                part->lo_minimal = false;

-                part->hi_minimal = true;

-                return;

-              }

+	      return;

           }

         }

 #endif /* USE_HEURISTIC */

-

-      /* Heuristic: if we've gone well beyond the call of duty, give up

-         and report halfway between our best results so far.  */

-      if (c >= ctxt->too_expensive)

-        {

-          OFFSET fxybest;

-          OFFSET fxbest IF_LINT (= 0);

-          OFFSET bxybest;

-          OFFSET bxbest IF_LINT (= 0);

-

-          /* Find forward diagonal that maximizes X + Y.  */

-          fxybest = -1;

-          for (d = fmax; d >= fmin; d -= 2)

-            {

-              OFFSET x = MIN (fd[d], xlim);

-              OFFSET y = x - d;

-              if (ylim < y)

-                {

-                  x = ylim + d;

-                  y = ylim;

-                }

-              if (fxybest < x + y)

-                {

-                  fxybest = x + y;

-                  fxbest = x;

-                }

-            }

-

-          /* Find backward diagonal that minimizes X + Y.  */

-          bxybest = OFFSET_MAX;

-          for (d = bmax; d >= bmin; d -= 2)

-            {

-              OFFSET x = MAX (xoff, bd[d]);

-              OFFSET y = x - d;

-              if (y < yoff)

-                {

-                  x = yoff + d;

-                  y = yoff;

-                }

-              if (x + y < bxybest)

-                {

-                  bxybest = x + y;

-                  bxbest = x;

-                }

-            }

-

-          /* Use the better of the two diagonals.  */

-          if ((xlim + ylim) - bxybest < fxybest - (xoff + yoff))

-            {

-              part->xmid = fxbest;

-              part->ymid = fxybest - fxbest;

-              part->lo_minimal = true;

-              part->hi_minimal = false;

-            }

-          else

-            {

-              part->xmid = bxbest;

-              part->ymid = bxybest - bxbest;

-              part->lo_minimal = false;

-              part->hi_minimal = true;

-            }

-          return;

-        }

     }

   #undef XREF_YREF_EQUAL

 }

@@ -452,7 +354,7 @@ diag (OFFSET xoff, OFFSET xlim, OFFSET y

 static bool

 compareseq (OFFSET xoff, OFFSET xlim, OFFSET yoff, OFFSET ylim,

-            bool find_minimal, struct context *ctxt)

+            struct context *ctxt)

 {

 #ifdef ELEMENT

   ELEMENT const *xv = ctxt->xvec; /* Help the compiler.  */

@@ -498,12 +400,12 @@ compareseq (OFFSET xoff, OFFSET xlim, OF

       struct partition part IF_LINT2 (= { .xmid = 0, .ymid = 0 });

       /* Find a point of correspondence in the middle of the vectors.  */

-      diag (xoff, xlim, yoff, ylim, find_minimal, &part, ctxt);

+      diag (xoff, xlim, yoff, ylim, &part, ctxt);

       /* Use the partitions to split this problem into subproblems.  */

-      if (compareseq (xoff, part.xmid, yoff, part.ymid, part.lo_minimal, ctxt))

+      if (compareseq (xoff, part.xmid, yoff, part.ymid, ctxt))

         return true;

-      if (compareseq (part.xmid, xlim, part.ymid, ylim, part.hi_minimal, ctxt))

+      if (compareseq (part.xmid, xlim, part.ymid, ylim, ctxt))

         return true;

     }

diff -up diffutils-3.3/src/analyze.c.me diffutils-3.3/src/analyze.c

--- diffutils-3.3/src/analyze.c.me	2018-08-10 14:06:53.473858743 +0200

+++ diffutils-3.3/src/analyze.c	2018-08-10 14:08:30.533579865 +0200

@@ -542,7 +542,6 @@ diff_2_files (struct comparison *cmp)

     {

       struct context ctxt;

       lin diags;

-      lin too_expensive;

       /* Allocate vectors for the results of comparison:

 	 a flag for each line of each file, saying whether that line

@@ -574,18 +573,11 @@ diff_2_files (struct comparison *cmp)

       ctxt.heuristic = speed_large_files;

-      /* Set TOO_EXPENSIVE to be approximate square root of input size,

-	 bounded below by 256.  */

-      too_expensive = 1;

-      for (;  diags != 0;  diags >>= 2)

-	too_expensive <<= 1;

-      ctxt.too_expensive = MAX (256, too_expensive);

-

       files[0] = cmp->file[0];

       files[1] = cmp->file[1];

       compareseq (0, cmp->file[0].nondiscarded_lines,

-		  0, cmp->file[1].nondiscarded_lines, minimal, &ctxt);

+		  0, cmp->file[1].nondiscarded_lines, &ctxt);

       free (ctxt.fdiag - (cmp->file[1].nondiscarded_lines + 1));

diff -up diffutils-3.3/src/diff.h.me diffutils-3.3/src/diff.h

--- diffutils-3.3/src/diff.h.me	2018-08-10 14:28:25.878169926 +0200

+++ diffutils-3.3/src/diff.h	2018-08-10 14:28:40.739127903 +0200

@@ -376,7 +376,7 @@ extern void print_sdiff_script (struct c

 extern char const change_letter[4];

 extern char const pr_program[];

 extern char *concat (char const *, char const *, char const *);

-extern bool (*lines_differ) (char const *, size_t, char const *, size_t) _GL_ATTRIBUTE_PURE;

+extern bool (*lines_differ) (char const *, size_t, char const *, size_t);

 extern bool lines_differ_singlebyte (char const *, size_t, char const *, size_t) _GL_ATTRIBUTE_PURE;

 #ifdef HANDLE_MULTIBYTE

 extern bool lines_differ_multibyte (char const *, size_t, char const *, size_t) _GL_ATTRIBUTE_PURE;