diff --git a/libctf/ctf-types.c b/libctf/ctf-types.c
index 044a1852c1a..d08d4542dc1 100644
--- a/libctf/ctf-types.c
+++ b/libctf/ctf-types.c
@@ -45,7 +45,7 @@ ctf_struct_member (ctf_dict_t *fp, ctf_lmember_t *dst, const ctf_type_t *tp,
     return -1;					/* errno is set for us.  */
 
   /* Already large.  */
-  if (tp->ctt_size == CTF_LSIZE_SENT)
+  if (tp->ctt_size >= CTF_LSTRUCT_THRESH)
     {
       ctf_lmember_t *lmp = (ctf_lmember_t *) vlen;
 
diff --git a/libctf/testsuite/lib/ctf-lib.exp b/libctf/testsuite/lib/ctf-lib.exp
index 4df6619606b..7175e14c30a 100644
--- a/libctf/testsuite/lib/ctf-lib.exp
+++ b/libctf/testsuite/lib/ctf-lib.exp
@@ -141,6 +141,8 @@ proc compile_link_one_host_cc { src output additional_args } {
 #
 #   link:
 #	If set, link the SOURCE together even if only one file is specified.
+#       If "objects", keep the input object files and pass them as additional
+#       arguments to LOOKUP.
 #
 #   link_flags:
 #	If set, extra flags to pass to the linker.
@@ -265,11 +267,14 @@ proc run_lookup_test { name } {
     # Compile the inputs and posibly link them together.
 
     set lookup_output ""
+    set objs {}
     if { [llength $opts(source)] > 0 } {
 	set lookup_flags ""
+	set ld_flags ""
 	if { $run_ld } {
 	    set lookup_output "tmpdir/out.so"
-	    set lookup_flags "-gctf -fPIC $shared $opts(link_flags)"
+	    set lookup_flags "-gctf -fPIC"
+	    set ld_flags "$shared $opts(link_flags)"
 	} else {
 	    set lookup_output "tmpdir/out.o"
 	    set lookup_flags "-gctf -fPIC -c"
@@ -280,19 +285,38 @@ proc run_lookup_test { name } {
 	if [board_info [target_info name] exists ldflags] {
 	    append lookup_flags " [board_info [target_info name] ldflags]"
 	}
-	set src {}
+	set objsrcs {}
+	set local_srcs {}
 	foreach sfile $opts(source) {
+	    set local_src [file join [file dirname $file] $sfile]
+	    lappend local_srcs $local_src
+
 	    if [is_remote host] {
-		lappend src [remote_download host [file join [file dirname $file] $sfile]]
+		set src [remote_download host [file join [file dirname $file] $sfile]]
 	    } else {
-		lappend src [file join [file dirname $file] $sfile]
+		set src [file join [file dirname $file] $sfile]
+	    }
+
+	    if { $opts(link) == "objects" } {
+		set obj "[file rootname $src].o"
+		set comp_output [prune_warnings [run_host_cmd "$CC_FOR_TARGET" "$CFLAGS_FOR_TARGET $lookup_flags $src -c -o $obj"]]
+
+		if { $comp_output != ""} {
+		    send_log "compilation of CTF program $local_src failed with <$comp_output>"
+		    fail $testname
+		    return 0
+		}
+		lappend objsrcs $obj
+		lappend objs $obj
+	    } else {
+		lappend objsrcs $src
 	    }
 	}
 
-	set comp_output [prune_warnings [run_host_cmd "$CC_FOR_TARGET" "$CFLAGS_FOR_TARGET $lookup_flags [concat $src] -o $lookup_output"]]
+	set comp_output [prune_warnings [run_host_cmd "$CC_FOR_TARGET" "$CFLAGS_FOR_TARGET $lookup_flags $ld_flags [concat $objsrcs] -o $lookup_output"]]
 
 	if { $comp_output != ""} {
-	    send_log "compilation of CTF program [concat $src] failed with <$comp_output>"
+	    send_log "compilation of CTF program [concat $local_srcs] failed with <$comp_output>"
 	    fail $testname
 	    return 0
 	}
@@ -306,12 +330,13 @@ proc run_lookup_test { name } {
 	}
     }
 
-    # Invoke the lookup program on the outputs, possibly through the wrapper.
+    # Invoke the lookup program on the outputs, possibly through the wrapper, including all
+    # the object file names if they were filled out.
 
     if { [llength $opts(wrapper)] == 0 } {
-	set results [run_host_cmd tmpdir/lookup $lookup_output]
+	set results [run_host_cmd tmpdir/lookup "$lookup_output $objs"]
     } else {
-	set results [run_host_cmd "$opts(wrapper) tmpdir/lookup" $lookup_output]
+	set results [run_host_cmd "$opts(wrapper) tmpdir/lookup" "$lookup_output $objs"]
     }
 
     if { [regexp {^UNSUPPORTED: (.*)$} $results -> reason] } {
diff --git a/libctf/testsuite/libctf-lookup/big-struct-corruption.c b/libctf/testsuite/libctf-lookup/big-struct-corruption.c
new file mode 100644
index 00000000000..2cc05be79cc
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/big-struct-corruption.c
@@ -0,0 +1,118 @@
+/* Determine whether libctf/33339 is fixed, if and only if GCC PR 121411 is also
+   fixed.  */
+
+#include "config.h"
+#include <ctf-api.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Determine whether the passed-in struct's member's offsets ever descend.  */
+static int
+offsets_ascending (ctf_dict_t *fp, ctf_id_t type)
+{
+  ctf_next_t *it = NULL;
+  ssize_t offset, last_offset = 0;
+
+  while ((offset = ctf_member_next (fp, type, &it, NULL, NULL, 0)) >= 0)
+    {
+      if (offset < last_offset)
+	return 0;
+      last_offset = offset;
+    }
+  if (ctf_errno (fp) != ECTF_NEXT_END)
+    {
+      fprintf (stderr, "Cannot check member offsets: %s\n",
+	       ctf_errmsg (ctf_errno (fp)));
+      exit (0);
+    }
+
+  return 1;
+}
+
+int
+main (int argc, char *argv[])
+{
+  ctf_archive_t *ctf;
+  ctf_dict_t *fp;
+  ctf_id_t type;
+  int err;
+
+  if (argc != 3)
+    {
+      fprintf (stderr, "Syntax: %s PROGRAM OBJ\n", argv[0]);
+      exit(1);
+    }
+
+  /* Check for bugginess of compiler.  */
+
+  if ((ctf = ctf_open (argv[2], NULL, &err)) == NULL)
+    {
+      fprintf (stderr, "Cannot open compiler object file %s: %s\n",
+	       argv[2], ctf_errmsg (err));
+      exit (1);
+    }
+
+  /* Verify that offsets only ascend.  */
+
+  if ((fp = ctf_arc_lookup_symbol_name (ctf, "huge_used", &type, &err)) == NULL)
+    {
+      fprintf (stderr, "UNSUPPORTED: compiler does not provide expected symbol.\n");
+      exit (0);
+    }
+
+  if (!offsets_ascending (fp, type))
+    {
+      fprintf (stderr, "UNSUPPORTED: GCC bug PR121411 detected.\n");
+      exit (0);
+    }
+
+  ctf_dict_close (fp);
+  ctf_close (ctf);
+
+  /* Check if test is disabled (e.g. on 32-bit).  */
+
+  if ((ctf = ctf_open (argv[1], NULL, &err)) == NULL)
+    {
+      fprintf (stderr, "Cannot open linked binary test file %s: %s\n",
+	       argv[1], ctf_errmsg (err));
+      exit (1);
+    }
+
+  if ((fp = ctf_arc_lookup_symbol_name (ctf, "test_disabled", &type, &err)) != NULL)
+    {
+      fprintf (stderr, "UNSUPPORTED: test not necessary on 32-bit targets.\n");
+      exit (0);
+    }
+
+  if ((fp = ctf_arc_lookup_symbol_name (ctf, "big_used", &type, &err)) == NULL)
+    {
+      fprintf (stderr, "big struct symbol not found.\n");
+      exit (1);
+    }
+
+  if (!offsets_ascending (fp, type))
+    {
+      fprintf (stderr, "large struct offsets incorrect.\n");
+      exit (1);
+    }
+  ctf_dict_close (fp);
+
+  if ((fp = ctf_arc_lookup_symbol_name (ctf, "huge_used", &type, &err)) == NULL)
+    {
+      fprintf (stderr, "huge struct symbol not found.\n");
+      exit (1);
+    }
+
+  if (!offsets_ascending (fp, type))
+    {
+      fprintf (stderr, "huge struct offsets incorrect.\n");
+      exit (1);
+    }
+
+  ctf_dict_close (fp);
+  ctf_close (ctf);
+
+  fprintf (stderr, "Large and huge structs working fine.\n");
+  exit (0);
+}
diff --git a/libctf/testsuite/libctf-lookup/big-struct-corruption.lk b/libctf/testsuite/libctf-lookup/big-struct-corruption.lk
new file mode 100644
index 00000000000..980cb0bcecc
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/big-struct-corruption.lk
@@ -0,0 +1,3 @@
+# source: big-struct-ctf.c
+# link: objects
+Large and huge structs working fine.
diff --git a/libctf/testsuite/libctf-lookup/big-struct-ctf.c b/libctf/testsuite/libctf-lookup/big-struct-ctf.c
new file mode 100644
index 00000000000..fc99a3e5878
--- /dev/null
+++ b/libctf/testsuite/libctf-lookup/big-struct-ctf.c
@@ -0,0 +1,72 @@
+#if defined (__SIZEOF_PTRDIFF_T__) && __SIZEOF_PTRDIFF_T__ > 4
+
+#define CONCAT_(a,b) a ## b
+#define CONCAT(a,b) CONCAT_(a, b)
+#define COUNT(name) CONCAT(name, __COUNTER__)
+#define MEMBNAME const char COUNT(memb)[1024 * 1024]
+#define MEMB10					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;					\
+  MEMBNAME;
+
+#define MEMB100					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10					\
+  MEMB10
+
+#define MEMB1000				\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100					\
+  MEMB100
+
+#define MEMB10000				\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000					\
+  MEMB1000
+
+struct big
+{
+  MEMB1000;
+};
+
+struct huge
+{
+  MEMB10000;
+};
+
+struct big big_used;
+struct huge huge_used;
+
+#else
+
+int test_disabled;
+
+#endif