diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 571b273c82..a04e6d8d6f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2013-04-19  Pedro Alves  <palves@redhat.com>
+
+	* alpha-tdep.c (heuristic_fence_post): Change type to int.
+	(alpha_heuristic_proc_start): Adjust to check -1 instead of
+	UINT_MAX.
+	* mips-tdep.c (heuristic_fence_post): Change type to int.
+	(heuristic_proc_start): Adjust to check -1 instead of UINT_MAX.
+
 2013-04-19  Pedro Alves  <palves@redhat.com>
 
 	* cris-tdep.c (usr_cmd_cris_version): Make unsigned.
diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c
index e39460545f..7696b42e12 100644
--- a/gdb/alpha-tdep.c
+++ b/gdb/alpha-tdep.c
@@ -1032,7 +1032,7 @@ static const struct frame_unwind alpha_sigtramp_frame_unwind = {
 /* Heuristic_proc_start may hunt through the text section for a long
    time across a 2400 baud serial line.  Allows the user to limit this
    search.  */
-static unsigned int heuristic_fence_post = 0;
+static int heuristic_fence_post = 0;
 
 /* Attempt to locate the start of the function containing PC.  We assume that
    the previous function ends with an about_to_return insn.  Not foolproof by
@@ -1059,7 +1059,7 @@ alpha_heuristic_proc_start (struct gdbarch *gdbarch, CORE_ADDR pc)
   if (func)
     return func;
 
-  if (heuristic_fence_post == UINT_MAX
+  if (heuristic_fence_post == -1
       || fence < tdep->vm_min_address)
     fence = tdep->vm_min_address;
 
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 9d9451c786..8e5d5d2cd8 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -787,7 +787,7 @@ static const signed char mips_reg3_to_reg[8] = { 16, 17, 2, 3, 4, 5, 6, 7 };
    time across a 2400 baud serial line.  Allows the user to limit this
    search.  */
 
-static unsigned int heuristic_fence_post = 0;
+static int heuristic_fence_post = 0;
 
 /* Number of bytes of storage in the actual machine representation for
    register N.  NOTE: This defines the pseudo register type so need to
@@ -4021,7 +4021,7 @@ heuristic_proc_start (struct gdbarch *gdbarch, CORE_ADDR pc)
   if (start_pc == 0)
     return 0;
 
-  if (heuristic_fence_post == UINT_MAX || fence < VM_MIN_ADDRESS)
+  if (heuristic_fence_post == -1 || fence < VM_MIN_ADDRESS)
     fence = VM_MIN_ADDRESS;
 
   instlen = mips_pc_is_mips (pc) ? MIPS_INSN32_SIZE : MIPS_INSN16_SIZE;