[PATCH 40/50] rtlanal.c:for_each_inc_dec

[Richard Sandiford <rdsandiford@googlemail.com>]

The old for_each_inc_dec callback had a for_each_rtx-like return value,
with >0 being returned directly, 0 meaning "continue" and <0 meaning
"skip subrtxes".  But there's no reason to distinguish the latter two
cases since auto-inc/dec expressions aren't allowed to contain other
auto-inc/dec expressions.  And if for_each_rtx is going away, there's
no longer any consistency argument for using the same interface.


gcc/
	* rtl.h (for_each_inc_dec_fn): Remove special case for -1.
	* cselib.c (cselib_record_autoinc_cb): Update accordingly.
	(cselib_record_sets): Likewise.
	* dse.c (emit_inc_dec_insn_before, check_for_inc_dec_1)
	(check_for_inc_dec): Likewise.
	* rtlanal.c (for_each_inc_dec_ops): Delete.
	(for_each_inc_dec_find_inc_dec): Take the MEM as argument,
	rather than a pointer to the memory address.  Replace
	for_each_inc_dec_ops argument with separate function and data
	arguments.  Abort on non-autoinc addresses.
	(for_each_inc_dec_find_mem): Delete.
	(for_each_inc_dec): Use FOR_EACH_SUBRTX_VAR to visit every
	autoinc MEM.

Index: gcc/rtl.h
===================================================================
--- gcc/rtl.h	2014-08-03 11:25:31.042163078 +0100
+++ gcc/rtl.h	2014-08-03 11:25:31.324165866 +0100
@@ -2293,9 +2293,8 @@ extern int for_each_rtx (rtx *, rtx_func
    within MEM that sets DEST to SRC + SRCOFF, or SRC if SRCOFF is
    NULL.  The callback is passed the same opaque ARG passed to
    for_each_inc_dec.  Return zero to continue looking for other
-   autoinc operations, -1 to skip OP's operands, and any other value
-   to interrupt the traversal and return that value to the caller of
-   for_each_inc_dec.  */
+   autoinc operations or any other value to interrupt the traversal and
+   return that value to the caller of for_each_inc_dec.  */
 typedef int (*for_each_inc_dec_fn) (rtx mem, rtx op, rtx dest, rtx src,
 				    rtx srcoff, void *arg);
 extern int for_each_inc_dec (rtx *, for_each_inc_dec_fn, void *arg);
Index: gcc/cselib.c
===================================================================
--- gcc/cselib.c	2014-08-03 11:25:09.536950464 +0100
+++ gcc/cselib.c	2014-08-03 11:25:31.323165856 +0100
@@ -2464,7 +2464,7 @@ cselib_record_autoinc_cb (rtx mem ATTRIB
 
   data->n_sets++;
 
-  return -1;
+  return 0;
 }
 
 /* Record the effects of any sets and autoincs in INSN.  */
@@ -2523,7 +2523,7 @@ cselib_record_sets (rtx insn)
 
   data.sets = sets;
   data.n_sets = n_sets_before_autoinc = n_sets;
-  for_each_inc_dec (&insn, cselib_record_autoinc_cb, &data);
+  for_each_inc_dec (&PATTERN (insn), cselib_record_autoinc_cb, &data);
   n_sets = data.n_sets;
 
   /* Look up the values that are read.  Do this before invalidating the
Index: gcc/dse.c
===================================================================
--- gcc/dse.c	2014-08-03 11:25:25.192105241 +0100
+++ gcc/dse.c	2014-08-03 11:25:31.323165856 +0100
@@ -895,7 +895,7 @@ emit_inc_dec_insn_before (rtx mem ATTRIB
 
   emit_insn_before (new_insn, insn);
 
-  return -1;
+  return 0;
 }
 
 /* Before we delete INSN_INFO->INSN, make sure that the auto inc/dec, if it
@@ -908,7 +908,8 @@ check_for_inc_dec_1 (insn_info_t insn_in
   rtx insn = insn_info->insn;
   rtx note = find_reg_note (insn, REG_INC, NULL_RTX);
   if (note)
-    return for_each_inc_dec (&insn, emit_inc_dec_insn_before, insn_info) == 0;
+    return for_each_inc_dec (&PATTERN (insn), emit_inc_dec_insn_before,
+			     insn_info) == 0;
   return true;
 }
 
@@ -927,7 +928,8 @@ check_for_inc_dec (rtx insn)
   insn_info.fixed_regs_live = NULL;
   note = find_reg_note (insn, REG_INC, NULL_RTX);
   if (note)
-    return for_each_inc_dec (&insn, emit_inc_dec_insn_before, &insn_info) == 0;
+    return for_each_inc_dec (&PATTERN (insn), emit_inc_dec_insn_before,
+			     &insn_info) == 0;
   return true;
 }
 
Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c	2014-08-03 11:25:31.043163088 +0100
+++ gcc/rtlanal.c	2014-08-03 11:25:31.325165876 +0100
@@ -3105,49 +3105,32 @@ for_each_rtx (rtx *x, rtx_function f, vo
 
 \f
 
-/* Data structure that holds the internal state communicated between
-   for_each_inc_dec, for_each_inc_dec_find_mem and
-   for_each_inc_dec_find_inc_dec.  */
-
-struct for_each_inc_dec_ops {
-  /* The function to be called for each autoinc operation found.  */
-  for_each_inc_dec_fn fn;
-  /* The opaque argument to be passed to it.  */
-  void *arg;
-  /* The MEM we're visiting, if any.  */
-  rtx mem;
-};
-
-static int for_each_inc_dec_find_mem (rtx *r, void *d);
-
-/* Find PRE/POST-INC/DEC/MODIFY operations within *R, extract the
-   operands of the equivalent add insn and pass the result to the
-   operator specified by *D.  */
+/* MEM has a PRE/POST-INC/DEC/MODIFY address X.  Extract the operands of
+   the equivalent add insn and pass the result to FN, using DATA as the
+   final argument.  */
 
 static int
-for_each_inc_dec_find_inc_dec (rtx *r, void *d)
+for_each_inc_dec_find_inc_dec (rtx mem, for_each_inc_dec_fn fn, void *data)
 {
-  rtx x = *r;
-  struct for_each_inc_dec_ops *data = (struct for_each_inc_dec_ops *)d;
-
+  rtx x = XEXP (mem, 0);
   switch (GET_CODE (x))
     {
     case PRE_INC:
     case POST_INC:
       {
-	int size = GET_MODE_SIZE (GET_MODE (data->mem));
+	int size = GET_MODE_SIZE (GET_MODE (mem));
 	rtx r1 = XEXP (x, 0);
 	rtx c = gen_int_mode (size, GET_MODE (r1));
-	return data->fn (data->mem, x, r1, r1, c, data->arg);
+	return fn (mem, x, r1, r1, c, data);
       }
 
     case PRE_DEC:
     case POST_DEC:
       {
-	int size = GET_MODE_SIZE (GET_MODE (data->mem));
+	int size = GET_MODE_SIZE (GET_MODE (mem));
 	rtx r1 = XEXP (x, 0);
 	rtx c = gen_int_mode (-size, GET_MODE (r1));
-	return data->fn (data->mem, x, r1, r1, c, data->arg);
+	return fn (mem, x, r1, r1, c, data);
       }
 
     case PRE_MODIFY:
@@ -3155,69 +3138,43 @@ for_each_inc_dec_find_inc_dec (rtx *r, v
       {
 	rtx r1 = XEXP (x, 0);
 	rtx add = XEXP (x, 1);
-	return data->fn (data->mem, x, r1, add, NULL, data->arg);
-      }
-
-    case MEM:
-      {
-	rtx save = data->mem;
-	int ret = for_each_inc_dec_find_mem (r, d);
-	data->mem = save;
-	return ret;
+	return fn (mem, x, r1, add, NULL, data);
       }
 
     default:
-      return 0;
-    }
-}
-
-/* If *R is a MEM, find PRE/POST-INC/DEC/MODIFY operations within its
-   address, extract the operands of the equivalent add insn and pass
-   the result to the operator specified by *D.  */
-
-static int
-for_each_inc_dec_find_mem (rtx *r, void *d)
-{
-  rtx x = *r;
-  if (x != NULL_RTX && MEM_P (x))
-    {
-      struct for_each_inc_dec_ops *data = (struct for_each_inc_dec_ops *) d;
-      int result;
-
-      data->mem = x;
-
-      result = for_each_rtx (&XEXP (x, 0), for_each_inc_dec_find_inc_dec,
-			     data);
-      if (result)
-	return result;
-
-      return -1;
+      gcc_unreachable ();
     }
-  return 0;
 }
 
-/* Traverse *X looking for MEMs, and for autoinc operations within
-   them.  For each such autoinc operation found, call FN, passing it
+/* Traverse *LOC looking for MEMs that have autoinc addresses.
+   For each such autoinc operation found, call FN, passing it
    the innermost enclosing MEM, the operation itself, the RTX modified
    by the operation, two RTXs (the second may be NULL) that, once
    added, represent the value to be held by the modified RTX
-   afterwards, and ARG.  FN is to return -1 to skip looking for other
-   autoinc operations within the visited operation, 0 to continue the
-   traversal, or any other value to have it returned to the caller of
+   afterwards, and DATA.  FN is to return 0 to continue the
+   traversal or any other value to have it returned to the caller of
    for_each_inc_dec.  */
 
 int
-for_each_inc_dec (rtx *x,
+for_each_inc_dec (rtx *loc,
 		  for_each_inc_dec_fn fn,
-		  void *arg)
+		  void *data)
 {
-  struct for_each_inc_dec_ops data;
-
-  data.fn = fn;
-  data.arg = arg;
-  data.mem = NULL;
-
-  return for_each_rtx (x, for_each_inc_dec_find_mem, &data);
+  subrtx_var_iterator::array_type array;
+  FOR_EACH_SUBRTX_VAR (iter, array, *loc, NONCONST)
+    {
+      rtx mem = *iter;
+      if (mem
+	  && MEM_P (mem)
+	  && GET_RTX_CLASS (GET_CODE (XEXP (mem, 0))) == RTX_AUTOINC)
+	{
+	  int res = for_each_inc_dec_find_inc_dec (mem, fn, data);
+	  if (res != 0)
+	    return res;
+	  iter.skip_subrtxes ();
+	}
+    }
+  return 0;
 }
 
 \f