diff --git a/runtime/doc/todo.txt b/runtime/doc/todo.txt
index bde8146..9dc6a02 100644
--- a/runtime/doc/todo.txt
+++ b/runtime/doc/todo.txt
@@ -1093,6 +1093,7 @@
    Use register_shell_extension()? (George Reilly, 2010 May 26)
    Ron's version: http://dev.ronware.org/p/vim/finfo?name=gvim.nsi
 - Persistent undo bugs / fixes:
+    - check for sizeof(time_t) results in compiler warning in misc2.c
     - Memory leak reproduced by Dominique Pelle, 2010 May 28.
     - When there is no undo info (undolevels negative), delete the undo file.
     - Need to check all values for evil manipulation.
diff --git a/src/auto/configure b/src/auto/configure
index 34de4f3..77dea5d 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -11238,6 +11238,49 @@
 _ACEOF
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking size of time_t" >&5
+$as_echo_n "checking size of time_t... " >&6; }
+if test "${ac_cv_sizeof_time_t+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test "$cross_compiling" = yes; then :
+  as_fn_error "failed to compile test program" "$LINENO" 5
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#include <stdio.h>
+#if STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#endif
+#include <time.h>
+main()
+{
+  FILE *f=fopen("conftestval", "w");
+  if (!f) exit(1);
+  fprintf(f, "%d\n", (int)sizeof(time_t));
+  exit(0);
+}
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  ac_cv_sizeof_time_t=`cat conftestval`
+else
+  as_fn_error "failed to determine sizeof(time_t)" "$LINENO" 5
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sizeof_time_t" >&5
+$as_echo "$ac_cv_sizeof_time_t" >&6; }
+cat >>confdefs.h <<_ACEOF
+#define SIZEOF_TIME_T $ac_cv_sizeof_time_t
+_ACEOF
+
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking uint32_t is 32 bits" >&5
 $as_echo_n "checking uint32_t is 32 bits... " >&6; }
 if test "$cross_compiling" = yes; then :
diff --git a/src/config.h.in b/src/config.h.in
index c57cd2f..1099531 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -39,6 +39,9 @@
 /* Defined to the size of an int */
 #undef SIZEOF_INT
 
+/* Defined to the size of time_t */
+#undef SIZEOF_TIME_T
+
 /* Define when wchar_t is only 2 bytes. */
 #undef SMALL_WCHAR_T
 
diff --git a/src/configure.in b/src/configure.in
index 1d8cb09..35ecde3 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -2988,6 +2988,29 @@
 AC_MSG_RESULT($ac_cv_sizeof_int)
 AC_DEFINE_UNQUOTED(SIZEOF_INT, $ac_cv_sizeof_int)
 
+dnl Figure out sizeof(time_t) so that it can be used in #ifdef.
+AC_MSG_CHECKING(size of time_t)
+AC_CACHE_VAL(ac_cv_sizeof_time_t,
+	[AC_TRY_RUN([
+#include <stdio.h>
+#if STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#endif
+#include <time.h>
+main()
+{
+  FILE *f=fopen("conftestval", "w");
+  if (!f) exit(1);
+  fprintf(f, "%d\n", (int)sizeof(time_t));
+  exit(0);
+}],
+	    ac_cv_sizeof_time_t=`cat conftestval`,
+	    AC_MSG_ERROR([failed to determine sizeof(time_t)]),
+	    AC_MSG_ERROR([failed to compile test program]))])
+AC_MSG_RESULT($ac_cv_sizeof_time_t)
+AC_DEFINE_UNQUOTED(SIZEOF_TIME_T, $ac_cv_sizeof_time_t)
+
 dnl Make sure that uint32_t is really 32 bits unsigned.
 AC_MSG_CHECKING([uint32_t is 32 bits])
 AC_TRY_RUN([
diff --git a/src/misc2.c b/src/misc2.c
index f5bad9c..f35019d 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -6260,9 +6260,10 @@
     /* time_t can be up to 8 bytes in size, more than long_u, thus we
      * can't use put_bytes() here.
      * Another problem is that ">>" may do an arithmetic shift that keeps the
-     * sign.  A cast to long_u may truncate if time_t is 8 bytes.  So only use
-     * a cast when it is 4 bytes, it's safe to assume that long_u is 4 bytes
-     * or more and when using 8 bytes the top bit won't be set. */
+     * sign.  This happens for large values of wtime.  A cast to long_u may
+     * truncate if time_t is 8 bytes.  So only use a cast when it is 4 bytes,
+     * it's safe to assume that long_u is 4 bytes or more and when using 8
+     * bytes the top bit won't be set. */
     for (i = 7; i >= 0; --i)
     {
 	if (i + 1 > (int)sizeof(time_t))
@@ -6270,11 +6271,11 @@
 	    putc(0, fd);
 	else
 	{
-	    /* use "i" in condition to avoid compiler warning */
-	    if (i >= 0 && sizeof(time_t) > 4)
-		c = wtime >> (i * 8);
-	    else
-		c = (long_u)wtime >> (i * 8);
+#if defined(SIZEOF_TIME_T) && SIZEOF_TIME_T > 4
+	    c = wtime >> (i * 8);
+#else
+	    c = (long_u)wtime >> (i * 8);
+#endif
 	    putc(c, fd);
 	}
     }
diff --git a/src/testdir/Make_amiga.mak b/src/testdir/Make_amiga.mak
index 96215c0..bc9638c 100644
--- a/src/testdir/Make_amiga.mak
+++ b/src/testdir/Make_amiga.mak
@@ -26,7 +26,8 @@
 		test48.out test51.out test53.out test54.out test55.out \
 		test56.out test57.out test58.out test59.out test60.out \
 		test61.out test62.out test63.out test64.out test65.out \
-		test66.out test67.out test68.out test69.out
+		test66.out test67.out test68.out test69.out test70.out \
+		test71.out test72.out
 
 .SUFFIXES: .in .out
 
@@ -115,3 +116,6 @@
 test67.out: test67.in
 test68.out: test68.in
 test69.out: test69.in
+test70.out: test70.in
+test71.out: test71.in
+test72.out: test72.in
diff --git a/src/testdir/Make_dos.mak b/src/testdir/Make_dos.mak
index 4b1af5f..6deca3d 100644
--- a/src/testdir/Make_dos.mak
+++ b/src/testdir/Make_dos.mak
@@ -27,7 +27,7 @@
 		test30.out test31.out test32.out test33.out test34.out \
 		test37.out test38.out test39.out test40.out test41.out \
 		test42.out test52.out test65.out test66.out test67.out \
-		test68.out test69.out test71.out
+		test68.out test69.out test71.out test72.out
 
 SCRIPTS32 =	test50.out test70.out
 
diff --git a/src/testdir/Make_ming.mak b/src/testdir/Make_ming.mak
index 960f5b2..0024a4e 100644
--- a/src/testdir/Make_ming.mak
+++ b/src/testdir/Make_ming.mak
@@ -46,7 +46,7 @@
 		test30.out test31.out test32.out test33.out test34.out \
 		test37.out test38.out test39.out test40.out test41.out \
 		test42.out test52.out test65.out test66.out test67.out \
-		test68.out test69.out test71.out
+		test68.out test69.out test71.out test72.out
 
 SCRIPTS32 =	test50.out test70.out
 
diff --git a/src/testdir/Make_os2.mak b/src/testdir/Make_os2.mak
index 426fb23..ccbdb3e 100644
--- a/src/testdir/Make_os2.mak
+++ b/src/testdir/Make_os2.mak
@@ -26,7 +26,8 @@
 		test48.out test51.out test53.out test54.out test55.out \
 		test56.out test57.out test58.out test59.out test60.out \
 		test61.out test62.out test63.out test64.out test65.out \
-		test66.out test67.out test68.out test69.out
+		test66.out test67.out test68.out test69.out test70.out \
+		test71.out test72.out
 
 .SUFFIXES: .in .out
 
diff --git a/src/testdir/Make_vms.mms b/src/testdir/Make_vms.mms
index acd5c65..afeb9fa 100644
--- a/src/testdir/Make_vms.mms
+++ b/src/testdir/Make_vms.mms
@@ -69,7 +69,8 @@
 	 test48.out test51.out test53.out test54.out test55.out \
 	 test56.out test57.out test60.out \
 	 test61.out test62.out test63.out test64.out test65.out \
-	 test66.out test67.out test68.out test69.out
+	 test66.out test67.out test68.out test69.out test70.out \
+	 test71.out test72.out
 
 .IFDEF WANT_GUI
 SCRIPT_GUI = test16.out
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index 53e0854..f970b26 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -23,7 +23,7 @@
 		test54.out test55.out test56.out test57.out test58.out \
 		test59.out test60.out test61.out test62.out test63.out \
 		test64.out test65.out test66.out test67.out test68.out \
-		test69.out test70.out test71.out
+		test69.out test70.out test71.out test72.out
 
 SCRIPTS_GUI = test16.out
 
diff --git a/src/testdir/test61.in b/src/testdir/test61.in
index 909d123..7ce72e6 100644
--- a/src/testdir/test61.in
+++ b/src/testdir/test61.in
@@ -50,53 +50,6 @@
 obbbb:set ul=100
 :undojoin
 occccu:.w >>test.out
-:"
-:" Test 'undofile': first a simple one-line change.
-:set nocp ul=100 undofile
-:e! Xtestfile
-ggdGithis is one line:set ul=100
-:s/one/ONE/
-:set ul=100
-:w
-:bwipe!
-:e Xtestfile
-u:.w >>test.out
-:"
-:" Test 'undofile', change in original file fails check
-:set noundofile
-:e! Xtestfile
-:s/line/Line/
-:w
-:set undofile
-:bwipe!
-:e Xtestfile
-u:.w >>test.out
-:"
-:" Test 'undofile', add 10 lines, delete 6 lines, undo 3
-:set undofile
-ggdGione
-two
-three
-four
-five
-six
-seven
-eight
-nine
-ten:set ul=100
-3Gdd:set ul=100
-dd:set ul=100
-dd:set ul=100
-dd:set ul=100
-dd:set ul=100
-dd:set ul=100
-:w
-:bwipe!
-:e Xtestfile
-uuu:w >>test.out
-:"
-:" Rename the undo file so that it gets cleaned up.
-:call rename(".Xtestfile.un~", "Xtestundo")
 :qa!
 ENDTEST
 
diff --git a/src/testdir/test61.ok b/src/testdir/test61.ok
index ea88c07..020dd53 100644
--- a/src/testdir/test61.ok
+++ b/src/testdir/test61.ok
@@ -22,12 +22,3 @@
 123456abc
 aaaa
 aaaa
-this is one line
-this is ONE Line
-one
-two
-six
-seven
-eight
-nine
-ten
diff --git a/src/testdir/test72.in b/src/testdir/test72.in
new file mode 100644
index 0000000..a5674b5
--- /dev/null
+++ b/src/testdir/test72.in
@@ -0,0 +1,60 @@
+Tests for undo file.
+Since this script is sourced we need to explicitly break changes up in
+undo-able pieces.  Do that by setting 'undolevels'.
+
+STARTTEST
+:so small.vim
+:"
+:" Test 'undofile': first a simple one-line change.
+:set nocp ul=100 undofile
+:e! Xtestfile
+ggdGithis is one line:set ul=100
+:s/one/ONE/
+:set ul=100
+:w
+:bwipe!
+:e Xtestfile
+u:.w! test.out
+:"
+:" Test 'undofile', change in original file fails check
+:set noundofile
+:e! Xtestfile
+:s/line/Line/
+:w
+:set undofile
+:bwipe!
+:e Xtestfile
+u:.w >>test.out
+:"
+:" Test 'undofile', add 10 lines, delete 6 lines, undo 3
+:set undofile
+ggdGione
+two
+three
+four
+five
+six
+seven
+eight
+nine
+ten:set ul=100
+3Gdd:set ul=100
+dd:set ul=100
+dd:set ul=100
+dd:set ul=100
+dd:set ul=100
+dd:set ul=100
+:w
+:bwipe!
+:e Xtestfile
+uuu:w >>test.out
+:"
+:" Rename the undo file so that it gets cleaned up.
+:call rename(".Xtestfile.un~", "Xtestundo")
+:qa!
+ENDTEST
+
+1111 -----
+2222 -----
+
+123456789
diff --git a/src/testdir/test72.ok b/src/testdir/test72.ok
new file mode 100644
index 0000000..66e7250
--- /dev/null
+++ b/src/testdir/test72.ok
@@ -0,0 +1,9 @@
+this is one line
+this is ONE Line
+one
+two
+six
+seven
+eight
+nine
+ten
diff --git a/src/undo.c b/src/undo.c
index 958c6d2..5b04986 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -858,6 +858,8 @@
 	}
 	vim_memset(array, 0, sizeof(char_u *) * uep->ue_size);
     }
+    else
+	array = NULL;
     uep->ue_array = array;
 
     for (i = 0; i < uep->ue_size; ++i)
@@ -1365,7 +1367,6 @@
 	if (num_read_uhps >= num_head)
 	{
 	    corruption_error("num_head", file_name);
-	    u_free_uhp(uhp);
 	    goto error;
 	}
 
@@ -1442,7 +1443,7 @@
          * culling was done at undofile write time, and there can be uh_seq
          * gaps in the uhps.
          */
-        for (i = num_read_uhps - 1; i >= -1; i--)
+        for (i = num_read_uhps - 1; ; --i)
         {
             /* if i == -1, we've hit the leftmost side of the table, so insert
              * at uhp_table[0]. */