rtl.def (DEFINE_COND_EXEC): New.

	* rtl.def (DEFINE_COND_EXEC): New.
	* md.texi: Document it.

	* gensupport.c (input_file): Remove.
	(struct queue_elem): Add lineno.
	(rtx_ready_queue): Remove.
	(errors): New.
	(predicable_default): New.
	(predicable_true, predicable_false): New.
	(define_attr_queue, define_attr_tail): New.
	(define_insn_queue, define_insn_tail): New.
	(define_cond_exec_queue, define_cond_exec_tail): New.
	(other_queue, other_tail): New.
	(queue_pattern): New.
	(process_rtx): Add patterns to the appropriate queues.
	(is_predicable, identify_predicable_attribute): New.
	(n_alternatives, collect_insn_data): New.
	(alter_predicate_for_insn, alter_test_for_insn): New.
	(shift_output_template, alter_output_for_insn): New.
	(process_one_cond_exec, process_define_cond_exec): New.
	(init_md_reader): Read the entire file.  Process define_cond_exec.
	(read_md_rtx): Return elements from the queues.

From-SVN: r33751

1 files changed, 710 insertions, 90 deletions

diff --git a/gcc/gensupport.c b/gcc/gensupport.c
index 2de3f44..317d359 100644
--- a/gcc/gensupport.c
+++ b/gcc/gensupport.c
@@ -32,19 +32,49 @@ struct obstack *rtl_obstack = &obstack;
 #define obstack_chunk_alloc xmalloc
 #define obstack_chunk_free free
 
-static FILE *input_file;
-
 static int sequence_num;
+static int errors;
+
+static int predicable_default;
+static const char *predicable_true;
+static const char *predicable_false;
+
+/* We initially queue all patterns, process the define_insn and
+   define_cond_exec patterns, then return them one at a time.  */
 
-struct queue_elem {
-    rtx data;
-    struct queue_elem *next;
+struct queue_elem
+{
+  rtx data;
+  int lineno;
+  struct queue_elem *next;
 };
 
-static struct queue_elem *rtx_ready_queue;
+static struct queue_elem *define_attr_queue;
+static struct queue_elem **define_attr_tail = &define_attr_queue;
+static struct queue_elem *define_insn_queue;
+static struct queue_elem **define_insn_tail = &define_insn_queue;
+static struct queue_elem *define_cond_exec_queue;
+static struct queue_elem **define_cond_exec_tail = &define_cond_exec_queue;
+static struct queue_elem *other_queue;
+static struct queue_elem **other_tail = &other_queue;
 
+static void queue_pattern PARAMS ((rtx, struct queue_elem ***, int));
 static void remove_constraints PARAMS ((rtx));
-static void process_rtx PARAMS ((rtx *));
+static void process_rtx PARAMS ((rtx, int));
+
+static int is_predicable PARAMS ((struct queue_elem *));
+static void identify_predicable_attribute PARAMS ((void));
+static int n_alternatives PARAMS ((const char *));
+static void collect_insn_data PARAMS ((rtx, int *, int *));
+static rtx alter_predicate_for_insn PARAMS ((rtx, int, int, int));
+static const char *alter_test_for_insn PARAMS ((struct queue_elem *,
+						struct queue_elem *));
+static char *shift_output_template PARAMS ((char *, const char *, int));
+static const char *alter_output_for_insn PARAMS ((struct queue_elem *,
+						  struct queue_elem *,
+						  int, int));
+static void process_one_cond_exec PARAMS ((struct queue_elem *));
+static void process_define_cond_exec PARAMS ((void));
 
 void
 message_with_line VPARAMS ((int lineno, const char *msg, ...))
@@ -69,6 +99,22 @@ message_with_line VPARAMS ((int lineno, const char *msg, ...))
   va_end (ap);
 }
 
+/* Queue PATTERN on LIST_TAIL.  */
+
+static void
+queue_pattern (pattern, list_tail, lineno)
+     rtx pattern;
+     struct queue_elem ***list_tail;
+     int lineno;
+{
+  struct queue_elem *e = (struct queue_elem *) xmalloc (sizeof (*e));
+  e->data = pattern;
+  e->lineno = lineno;
+  e->next = NULL;
+  **list_tail = e;
+  *list_tail = &e->next;
+}
+
 /* Recursively remove constraints from an rtx.  */
 
 static void
@@ -103,64 +149,617 @@ remove_constraints (part)
       }
 }
 
-/* Handle any synthetic top level rtx, i.e. anything except:
-       DEFINE_INSN
-       DEFINE_EXPAND
-       DEFINE_SPLIT
-       DEFINE_PEEPHOLE
-       DEFINE_PEEPHOLE2
-       DEFINE_ATTRIBUTE
-       DEFINE_FUNCTION_UNIT
-       DEFINE_ASM_ATTRIBUTES */
+/* Process a top level rtx in some way, queueing as appropriate.  */
 
 static void
-process_rtx (desc)
-    rtx* desc;
-{
-  if (GET_CODE (*desc) == DEFINE_INSN_AND_SPLIT) 
-    {
-      struct queue_elem* elem = xmalloc (sizeof (struct queue_elem));
-      const char *split_cond;
-  
-      /* Create a split with values from the insn_and_split. */
-      rtx split = rtx_alloc (DEFINE_SPLIT);
-      XEXP (split, 0) = copy_rtx (XEXP (*desc, 1));
-      remove_constraints (XEXP (split, 0));
-      split_cond = XSTR (split, 1) = XSTR (*desc, 4);
-  
-      /* If the split condition starts with "&&", append it to the
-         insn condition to create the new split condition.  */
-      if (split_cond[0] == '&' && split_cond[1] == '&')
-        {
-	const char *insn_cond = XSTR (*desc, 2);
-  	char *combined = 
-  	    xmalloc (strlen (insn_cond) + strlen (split_cond) + 1);
-  	strcpy (combined, insn_cond);
-  	strcat (combined, split_cond);
-  	XSTR (split, 1) = combined;
-        }
-  
-      XVEC (split, 2) = XVEC (*desc, 5);
-      XSTR (split, 3) = XSTR (*desc, 6);
-  
-      /* Fix up the DEFINE_INSN.  */
-      PUT_CODE (*desc, DEFINE_INSN);
-      XVEC (*desc, 4) = XVEC (*desc, 7);
-  
-      /* Return the DEFINE_INSN part, and put the DEFINE_SPLIT
-         in the queue.  */
-      elem->next = rtx_ready_queue;
-      elem->data = split;	
-      rtx_ready_queue = elem;  
+process_rtx (desc, lineno)
+     rtx desc;
+     int lineno;
+{
+  switch (GET_CODE (desc))
+    {
+    case DEFINE_INSN:
+      queue_pattern (desc, &define_insn_tail, lineno);
+      break;
+
+    case DEFINE_COND_EXEC:
+      queue_pattern (desc, &define_cond_exec_tail, lineno);
+      break;
+
+    case DEFINE_ATTR:
+      queue_pattern (desc, &define_attr_tail, lineno);
+      break;
+
+    case DEFINE_INSN_AND_SPLIT:
+      {
+	const char *split_cond;
+	rtx split;
+
+	/* Create a split with values from the insn_and_split. */
+	split = rtx_alloc (DEFINE_SPLIT);
+	XEXP (split, 0) = copy_rtx (XEXP (desc, 1));
+	remove_constraints (XEXP (split, 0));
+
+	/* If the split condition starts with "&&", append it to the
+	   insn condition to create the new split condition.  */
+	split_cond = XSTR (desc, 4);
+	if (split_cond[0] == '&' && split_cond[1] == '&')
+	  {
+	    const char *insn_cond = XSTR (desc, 2);
+	    size_t insn_cond_len = strlen (insn_cond);
+	    size_t split_cond_len = strlen (split_cond);
+	    char *combined;
+
+	    combined = (char *) xmalloc (insn_cond_len + split_cond_len + 1);
+	    memcpy (combined, insn_cond, insn_cond_len);
+	    memcpy (combined + insn_cond_len, split_cond, split_cond_len + 1);
+
+	    split_cond = combined;
+	  }
+	XSTR (split, 1) = split_cond;
+	XVEC (split, 2) = XVEC (desc, 5);
+	XSTR (split, 3) = XSTR (desc, 6);
+
+	/* Fix up the DEFINE_INSN.  */
+	PUT_CODE (desc, DEFINE_INSN);
+	XVEC (desc, 4) = XVEC (desc, 7);
+
+	/* Queue them.  */
+	queue_pattern (desc, &define_insn_tail, lineno);
+	queue_pattern (split, &other_tail, lineno);
+	break;
+      }
+
+    default:
+      queue_pattern (desc, &other_tail, lineno);
+      break;
     }
 }
 
+/* Return true if attribute PREDICABLE is true for ELEM, which holds
+   a DEFINE_INSN.  */
+
+static int
+is_predicable (elem)
+     struct queue_elem *elem;
+{
+  rtvec vec = XVEC (elem->data, 4);
+  const char *value;
+  int i;
+
+  if (! vec)
+    return predicable_default;
+
+  for (i = GET_NUM_ELEM (vec) - 1; i >= 0; --i)
+    {
+      rtx sub = RTVEC_ELT (vec, i);
+      switch (GET_CODE (sub))
+	{
+	case SET_ATTR:
+	  if (strcmp (XSTR (sub, 0), "predicable") == 0)
+	    {
+	      value = XSTR (sub, 1);
+	      goto found;
+	    }
+	  break;
+
+	case SET_ATTR_ALTERNATIVE:
+	  if (strcmp (XSTR (sub, 0), "predicable") == 0)
+	    {
+	      message_with_line (elem->lineno,
+				 "multiple alternatives for `predicable'");
+	      errors = 1;
+	      return 0;
+	    }
+	  break;
+
+	case SET:
+	  if (GET_CODE (SET_DEST (sub)) != ATTR
+	      || strcmp (XSTR (SET_DEST (sub), 0), "predicable") != 0)
+	    break;
+	  sub = SET_SRC (sub);
+	  if (GET_CODE (sub) == CONST_STRING)
+	    {
+	      value = XSTR (sub, 0);
+	      goto found;
+	    }
+
+	  /* ??? It would be possible to handle this if we really tried.
+	     It's not easy though, and I'm not going to bother until it
+	     really proves necessary.  */
+	  message_with_line (elem->lineno,
+			     "non-constant value for `predicable'");
+	  errors = 1;
+	  return 0;
+
+	default:
+	  abort ();
+	}
+    }
+
+  return predicable_default;
+
+ found:
+  /* Verify that predicability does not vary on the alternative.  */
+  /* ??? It should be possible to handle this by simply eliminating
+     the non-predicable alternatives from the insn.  FRV would like
+     to do this.  Delay this until we've got the basics solid.  */
+  if (strchr (value, ',') != NULL)
+    {
+      message_with_line (elem->lineno,
+			 "multiple alternatives for `predicable'");
+      errors = 1;
+      return 0;
+    }
+
+  /* Find out which value we're looking at.  */
+  if (strcmp (value, predicable_true) == 0)
+    return 1;
+  if (strcmp (value, predicable_false) == 0)
+    return 0;
+
+  message_with_line (elem->lineno,
+		     "Unknown value `%s' for `predicable' attribute",
+		     value);
+  errors = 1;
+  return 0;
+}
+
+/* Examine the attribute "predicable"; discover its boolean values
+   and its default.  */
+
+static void
+identify_predicable_attribute ()
+{
+  struct queue_elem *elem;
+  char *true, *false;
+  const char *value;
+  size_t len;
+
+  /* Look for the DEFINE_ATTR for `predicable', which must exist.  */
+  for (elem = define_attr_queue; elem ; elem = elem->next)
+    if (strcmp (XSTR (elem->data, 0), "predicable") == 0)
+      goto found;
+
+  message_with_line (define_cond_exec_queue->lineno,
+		     "Attribute `predicable' not defined");
+  errors = 1;
+  return;
+
+ found:
+  value = XSTR (elem->data, 1);
+  len = strlen (value);
+  false = (char *) xmalloc (len + 1);
+  memcpy (false, value, len + 1);
+
+  true = strchr (false, ',');
+  if (true == NULL || strchr (++true, ',') != NULL)
+    {
+      message_with_line (elem->lineno,
+			 "Attribute `predicable' is not a boolean");
+      errors = 1;
+      return;
+    }
+  true[-1] = '\0';
+
+  predicable_true = true;
+  predicable_false = false;
+
+  switch (GET_CODE (XEXP (elem->data, 2)))
+    {
+    case CONST_STRING:
+      value = XSTR (XEXP (elem->data, 2), 0);
+      break;
+
+    case CONST:
+      message_with_line (elem->lineno,
+			 "Attribute `predicable' cannot be const");
+      errors = 1;
+      return;
+
+    default:
+      message_with_line (elem->lineno,
+			 "Attribute `predicable' must have a constant default");
+      errors = 1;
+      return;
+    }
+
+  if (strcmp (value, true) == 0)
+    predicable_default = 1;
+  else if (strcmp (value, false) == 0)
+    predicable_default = 0;
+  else
+    {
+      message_with_line (elem->lineno,
+			 "Unknown value `%s' for `predicable' attribute",
+			 value);
+      errors = 1;
+    }
+}
+
+/* Return the number of alternatives in constraint S.  */
+
+static int
+n_alternatives (s)
+     const char *s;
+{
+  int n = 1;
+
+  if (s)
+    while (*s)
+      n += (*s++ == ',');
+
+  return n;
+}
+
+/* Determine how many alternatives there are in INSN, and how many
+   operands.  */
+
+static void
+collect_insn_data (pattern, palt, pmax)
+     rtx pattern;
+     int *palt, *pmax;
+{
+  const char *fmt;
+  enum rtx_code code;
+  int i, j, len;
+
+  code = GET_CODE (pattern);
+  switch (code)
+    {
+    case MATCH_OPERAND:
+      *palt = n_alternatives (XSTR (pattern, 2));
+      /* FALLTHRU */
+
+    case MATCH_OPERATOR:
+    case MATCH_SCRATCH:
+    case MATCH_PARALLEL:
+    case MATCH_INSN:
+      i = XINT (pattern, 0);
+      if (i > *pmax)
+	*pmax = i;
+      break;
+
+    default:
+      break;
+    }
+
+  fmt = GET_RTX_FORMAT (code);
+  len = GET_RTX_LENGTH (code);
+  for (i = 0; i < len; i++)
+    {
+      switch (fmt[i])
+	{
+	case 'e': case 'u':
+	  collect_insn_data (XEXP (pattern, i), palt, pmax);
+	  break;
+
+	case 'V':
+	  if (XVEC (pattern, i) == NULL)
+	    break;
+	  /* FALLTHRU */
+	case 'E':
+	  for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
+	    collect_insn_data (XVECEXP (pattern, i, j), palt, pmax);
+	  break;
+
+	case 'i': case 'w': case '0': case 's': case 'S':
+	  break;
+
+	default:
+	  abort ();
+	}
+    }
+}
+
+static rtx
+alter_predicate_for_insn (pattern, alt, max_op, lineno)
+     rtx pattern;
+     int alt, max_op, lineno;
+{
+  const char *fmt;
+  enum rtx_code code;
+  int i, j, len;
+
+  code = GET_CODE (pattern);
+  switch (code)
+    {
+    case MATCH_OPERAND:
+      {
+	const char *c = XSTR (pattern, 2);
+
+	if (n_alternatives (c) != 1)
+	  {
+	    message_with_line (lineno,
+			       "Too many alternatives for operand %d",
+			       XINT (pattern, 0));
+	    errors = 1;
+	    return NULL;
+	  }
+
+	/* Replicate C as needed to fill out ALT alternatives.  */
+	if (c && *c && alt > 1)
+	  {
+	    size_t c_len = strlen (c);
+	    size_t len = alt * (c_len + 1);
+	    char *new_c = (char *) xmalloc (len);
+
+	    memcpy (new_c, c, c_len);
+	    for (i = 1; i < alt; ++i)
+	      {
+		new_c[i * (c_len + 1) - 1] = ',';
+		memcpy (&new_c[i * (c_len + 1)], c, c_len);
+	      }
+	    new_c[len - 1] = '\0';
+	    XSTR (pattern, 2) = new_c;
+	  }
+      }
+      /* FALLTHRU */
+
+    case MATCH_OPERATOR:
+    case MATCH_SCRATCH:
+    case MATCH_PARALLEL:
+    case MATCH_INSN:
+      XINT (pattern, 0) += max_op;
+      break;
+
+    default:
+      break;
+    }
+
+  fmt = GET_RTX_FORMAT (code);
+  len = GET_RTX_LENGTH (code);
+  for (i = 0; i < len; i++)
+    {
+      rtx r;
+
+      switch (fmt[i])
+	{
+	case 'e': case 'u':
+	  r = alter_predicate_for_insn (XEXP (pattern, i), alt,
+					max_op, lineno);
+	  if (r == NULL)
+	    return r;
+	  break;
+
+	case 'E':
+	  for (j = XVECLEN (pattern, i) - 1; j >= 0; --j)
+	    {
+	      r = alter_predicate_for_insn (XVECEXP (pattern, i, j),
+					    alt, max_op, lineno);
+	      if (r == NULL)
+		return r;
+	    }
+	  break;
+
+	case 'i': case 'w': case '0': case 's':
+	  break;
+
+	default:
+	  abort ();
+	}
+    }
+
+  return pattern;
+}
+
+static const char *
+alter_test_for_insn (ce_elem, insn_elem)
+     struct queue_elem *ce_elem, *insn_elem;
+{
+  const char *ce_test, *insn_test;
+  char *new_test;
+  size_t len, ce_len, insn_len;
+
+  ce_test = XSTR (ce_elem->data, 1);
+  insn_test = XSTR (insn_elem->data, 2);
+  if (!ce_test || *ce_test == '\0')
+    return insn_test;
+  if (!insn_test || *insn_test == '\0')
+    return ce_test;
+
+  ce_len = strlen (ce_test);
+  insn_len = strlen (insn_test);
+  len = 1 + ce_len + 1 + 4 + 1 + insn_len + 1 + 1;
+  new_test = (char *) xmalloc (len);
+
+  sprintf (new_test, "(%s) && (%s)", ce_test, insn_test);
+
+  return new_test;
+}
+
+/* Adjust all of the operand numbers in OLD to match the shift they'll
+   get from an operand displacement of DISP.  Return a pointer after the
+   adjusted string.  */
+
+static char *
+shift_output_template (new, old, disp)
+     char *new;
+     const char *old;
+     int disp;
+{
+  while (*old)
+    {
+      char c = *old++;
+      *new++ = c;
+      if (c == '%')
+	{
+	  c = *old++;
+	  if (ISDIGIT ((unsigned char) c))
+	    c += disp;
+	  else if (ISUPPER ((unsigned char) c)
+		   || ISLOWER ((unsigned char) c))
+	    {
+	      *new++ = c;
+	      c = *old++ + disp;
+	    }
+	  *new++ = c;
+	}
+    }
+
+  return new;
+}
+
+static const char *
+alter_output_for_insn (ce_elem, insn_elem, alt, max_op)
+     struct queue_elem *ce_elem, *insn_elem;
+     int alt, max_op;
+{
+  const char *ce_out, *insn_out;
+  char *new, *p;
+  size_t len, ce_len, insn_len;
+
+  /* ??? Could coordinate with genoutput to not duplicate code here.  */
+
+  ce_out = XSTR (ce_elem->data, 2);
+  insn_out = XSTR (insn_elem->data, 3);
+  if (!ce_out || *ce_out == '\0')
+    return insn_out;
+
+  ce_len = strlen (ce_out);
+  insn_len = strlen (insn_out);
+
+  if (*insn_out == '*')
+    /* You must take care of the predicate yourself.  */
+    return insn_out;
+
+  if (*insn_out == '@')
+    {
+      len = (ce_len + 1) * alt + insn_len + 1;
+      p = new = xmalloc (len);
+
+      do
+	{
+	  do
+	    *p++ = *insn_out++;
+	  while (ISSPACE ((unsigned char) *insn_out));
+
+	  if (*insn_out != '#')
+	    {
+	      p = shift_output_template (p, ce_out, max_op);
+	      *p++ = ' ';
+	    }
+
+	  do
+	    *p++ = *insn_out++;
+	  while (*insn_out && *insn_out != '\n');
+	}
+      while (*insn_out);
+      *p = '\0';
+    }
+  else
+    {
+      len = ce_len + 1 + insn_len + 1;
+      new = xmalloc (len);
+
+      p = shift_output_template (new, ce_out, max_op);
+      *p++ = ' ';
+      memcpy (p, insn_out, insn_len + 1);
+    }
+
+  return new;
+}
+
+/* Replicate insns as appropriate for the given DEFINE_COND_EXEC.  */
+
+static void
+process_one_cond_exec (ce_elem)
+     struct queue_elem *ce_elem;
+{
+  struct queue_elem *insn_elem;
+  for (insn_elem = define_insn_queue; insn_elem ; insn_elem = insn_elem->next)
+    {
+      int alternatives, max_operand;
+      rtx pred, insn, pattern;
+
+      if (! is_predicable (insn_elem))
+	continue;
+
+      alternatives = 1;
+      max_operand = -1;
+      collect_insn_data (insn_elem->data, &alternatives, &max_operand);
+      max_operand += 1;
+
+      if (XVECLEN (ce_elem->data, 0) != 1)
+	{
+	  message_with_line (ce_elem->lineno,
+			     "too many patterns in predicate");
+	  errors = 1;
+	  return;
+	}
+
+      pred = copy_rtx (XVECEXP (ce_elem->data, 0, 0));
+      pred = alter_predicate_for_insn (pred, alternatives, max_operand,
+				       ce_elem->lineno);
+      if (pred == NULL)
+	return;
+
+      /* Construct a new pattern for the new insn.  */
+      insn = copy_rtx (insn_elem->data);
+      XSTR (insn, 0) = "";
+      pattern = rtx_alloc (COND_EXEC);
+      XEXP (pattern, 0) = pred;
+      if (XVECLEN (insn, 1) == 1)
+	{
+	  XEXP (pattern, 1) = XVECEXP (insn, 1, 0);
+	  XVECEXP (insn, 1, 0) = pattern;
+	  PUT_NUM_ELEM (XVEC (insn, 1), 1);
+	}
+      else
+	{
+	  XEXP (pattern, 1) = rtx_alloc (PARALLEL);
+	  XVEC (XEXP (pattern, 1), 0) = XVEC (insn, 1);
+	  XVEC (insn, 1) = rtvec_alloc (1);
+	  XVECEXP (insn, 1, 0) = pattern;
+	}
+
+      XSTR (insn, 2) = alter_test_for_insn (ce_elem, insn_elem);
+      XSTR (insn, 3) = alter_output_for_insn (ce_elem, insn_elem,
+					      alternatives, max_operand);
+
+      /* ??? Set `predicable' to false.  Not crucial since it's really
+         only used here, and we won't reprocess this new pattern.  */
+
+      /* Put the new pattern on the `other' list so that it
+	 (a) is not reprocessed by other define_cond_exec patterns
+	 (b) appears after all normal define_insn patterns.
+
+	 ??? B is debatable.  If one has normal insns that match
+	 cond_exec patterns, they will be preferred over these
+	 generated patterns.  Whether this matters in practice, or if
+	 it's a good thing, or whether we should thread these new
+	 patterns into the define_insn chain just after their generator
+	 is something we'll have to experiment with.  */
+
+      queue_pattern (insn, &other_tail, insn_elem->lineno);
+    }
+}
+
+/* If we have any DEFINE_COND_EXEC patterns, expand the DEFINE_INSN
+   patterns appropriately.  */
+
+static void
+process_define_cond_exec ()
+{
+  struct queue_elem *elem;
+
+  identify_predicable_attribute ();
+  if (errors)
+    return;
+
+  for (elem = define_cond_exec_queue; elem ; elem = elem->next)
+    process_one_cond_exec (elem);
+}
+
 /* The entry point for initializing the reader.  */
 
-int 
+int
 init_md_reader (filename)
-    const char *filename;
+     const char *filename;
 {
+  FILE *input_file;
+  int c;
+
   read_rtx_filename = filename;
   input_file = fopen (filename, "r");
   if (input_file == 0)
@@ -170,52 +769,73 @@ init_md_reader (filename)
     }
 
   obstack_init (rtl_obstack);
+  errors = 0;
   sequence_num = 0;
-  rtx_ready_queue = NULL; 
 
-  return SUCCESS_EXIT_CODE;
-}
-
-
-/* The entry point for reading a single rtx from an md file.  */
-
-rtx 
-read_md_rtx (lineno, seqnr)
-    int *lineno;
-    int *seqnr;
-{ 
-  rtx desc;
-
-  if (rtx_ready_queue != NULL) 
+  /* Read the entire file.  */
+  while (1)
     {
-      desc = rtx_ready_queue->data;
-      rtx_ready_queue = rtx_ready_queue->next;
-    }
-  else 
-    {
-      int c;
+      rtx desc;
+      int lineno;
+
       c = read_skip_spaces (input_file);
       if (c == EOF)
-	return NULL;
+	break;
 
       ungetc (c, input_file);
+      lineno = read_rtx_lineno;
       desc = read_rtx (input_file);
-      process_rtx (&desc);
+      process_rtx (desc, lineno);
     }
-  *lineno = read_rtx_lineno;
+  fclose (input_file);
+
+  /* Process define_cond_exec patterns.  */
+  if (define_cond_exec_queue != NULL)
+    process_define_cond_exec ();
+
+  return errors ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;
+}
+
+/* The entry point for reading a single rtx from an md file.  */
+
+rtx
+read_md_rtx (lineno, seqnr)
+     int *lineno;
+     int *seqnr;
+{
+  struct queue_elem **queue, *elem;
+  rtx desc;
+
+  /* Read all patterns from a given queue before moving on to the next.  */
+  if (define_attr_queue != NULL)
+    queue = &define_attr_queue;
+  else if (define_insn_queue != NULL)
+    queue = &define_insn_queue;
+  else if (other_queue != NULL)
+    queue = &other_queue;
+  else
+    return NULL_RTX;
+
+  elem = *queue;
+  *queue = elem->next;
+  desc = elem->data;
+  *lineno = elem->lineno;
   *seqnr = sequence_num;
+
+  free (elem);
+
   switch (GET_CODE (desc))
     {
-      case DEFINE_INSN:
-      case DEFINE_EXPAND:
-      case DEFINE_SPLIT:
-      case DEFINE_PEEPHOLE:
-      case DEFINE_PEEPHOLE2:
-	sequence_num++;
-	break;
-
-      default:
-	break;
+    case DEFINE_INSN:
+    case DEFINE_EXPAND:
+    case DEFINE_SPLIT:
+    case DEFINE_PEEPHOLE:
+    case DEFINE_PEEPHOLE2:
+      sequence_num++;
+      break;
+
+    default:
+      break;
     }
 
   return desc;