re PR middle-end/42505 (loop canonicalization causes a lot of unnecessary temporary variables)

2010-07-10  Sandra Loosemore  <sandra@codesourcery.com>

	PR middle-end/42505

	gcc/
	* tree-inline.c (estimate_num_insns): Refactor builtin complexity
	lookup code into....
	* builtins.c (is_simple_builtin, is_inexpensive_builtin): ...these
	new functions.
	* tree.h (is_simple_builtin, is_inexpensive_builtin): Declare.
	* cfgloopanal.c (target_clobbered_regs): Define.
	(init_set_costs): Initialize target_clobbered_regs.
	(estimate_reg_pressure_cost): Add call_p argument.  When true,
	adjust the number of available registers to exclude the
	call-clobbered registers.
	* cfgloop.h (target_clobbered_regs): Declare.
	(estimate_reg_pressure_cost): Adjust declaration.
	* tree-ssa-loop-ivopts.c (struct ivopts_data): Add body_includes_call.
	(ivopts_global_cost_for_size): Pass it to estimate_reg_pressure_cost.
	(determine_set_costs): Dump target_clobbered_regs.
	(loop_body_includes_call): New function.
	(tree_ssa_iv_optimize_loop): Use it to initialize new field.
	* loop-invariant.c (gain_for_invariant): Adjust arguments to pass
	call_p flag through.
	(best_gain_for_invariant): Likewise.
	(find_invariants_to_move): Likewise.
	(move_single_loop_invariants): Likewise, using already-computed
	has_call field.

From-SVN: r162043

gcc/ChangeLog

+2010-07-10  Sandra Loosemore  <sandra@codesourcery.com>
+
+	PR middle-end/42505
+	* tree-inline.c (estimate_num_insns): Refactor builtin complexity
+	lookup code into....
+	* builtins.c (is_simple_builtin, is_inexpensive_builtin): ...these
+	new functions.
+	* tree.h (is_simple_builtin, is_inexpensive_builtin): Declare.
+	* cfgloopanal.c (target_clobbered_regs): Define.
+	(init_set_costs): Initialize target_clobbered_regs.
+	(estimate_reg_pressure_cost): Add call_p argument.  When true,
+	adjust the number of available registers to exclude the
+	call-clobbered registers.
+	* cfgloop.h (target_clobbered_regs): Declare.
+	(estimate_reg_pressure_cost): Adjust declaration.
+	* tree-ssa-loop-ivopts.c (struct ivopts_data): Add body_includes_call.
+	(ivopts_global_cost_for_size): Pass it to estimate_reg_pressure_cost.
+	(determine_set_costs): Dump target_clobbered_regs.
+	(loop_body_includes_call): New function.
+	(tree_ssa_iv_optimize_loop): Use it to initialize new field.
+	* loop-invariant.c (gain_for_invariant): Adjust arguments to pass
+	call_p flag through.
+	(best_gain_for_invariant): Likewise.
+	(find_invariants_to_move): Likewise.
+	(move_single_loop_invariants): Likewise, using already-computed
+	has_call field.
+
 2010-07-10  Richard Guenther  <rguenther@suse.de>
 	    Joern Rennecke  <joern.rennecke@embecosm.com>
 

gcc/builtins.c

@@ -13753,3 +13753,123 @@ set_builtin_user_assembler_name (tree decl, const char *asmspec)
       break;
     }
 }
+
+/* Return true if DECL is a builtin that expands to a constant or similarly
+   simple code.  */
+bool
+is_simple_builtin (tree decl)
+{
+  if (decl && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
+    switch (DECL_FUNCTION_CODE (decl))
+      {
+	/* Builtins that expand to constants.  */
+      case BUILT_IN_CONSTANT_P:
+      case BUILT_IN_EXPECT:
+      case BUILT_IN_OBJECT_SIZE:
+      case BUILT_IN_UNREACHABLE:
+	/* Simple register moves or loads from stack.  */
+      case BUILT_IN_RETURN_ADDRESS:
+      case BUILT_IN_EXTRACT_RETURN_ADDR:
+      case BUILT_IN_FROB_RETURN_ADDR:
+      case BUILT_IN_RETURN:
+      case BUILT_IN_AGGREGATE_INCOMING_ADDRESS:
+      case BUILT_IN_FRAME_ADDRESS:
+      case BUILT_IN_VA_END:
+      case BUILT_IN_STACK_SAVE:
+      case BUILT_IN_STACK_RESTORE:
+	/* Exception state returns or moves registers around.  */
+      case BUILT_IN_EH_FILTER:
+      case BUILT_IN_EH_POINTER:
+      case BUILT_IN_EH_COPY_VALUES:
+	return true;
+
+      default:
+	return false;
+      }
+
+  return false;
+}
+
+/* Return true if DECL is a builtin that is not expensive, i.e., they are
+   most probably expanded inline into reasonably simple code.  This is a
+   superset of is_simple_builtin.  */
+bool
+is_inexpensive_builtin (tree decl)
+{
+  if (!decl)
+    return false;
+  else if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_MD)
+    return true;
+  else if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
+    switch (DECL_FUNCTION_CODE (decl))
+      {
+      case BUILT_IN_ABS:
+      case BUILT_IN_ALLOCA:
+      case BUILT_IN_BSWAP32:
+      case BUILT_IN_BSWAP64:
+      case BUILT_IN_CLZ:
+      case BUILT_IN_CLZIMAX:
+      case BUILT_IN_CLZL:
+      case BUILT_IN_CLZLL:
+      case BUILT_IN_CTZ:
+      case BUILT_IN_CTZIMAX:
+      case BUILT_IN_CTZL:
+      case BUILT_IN_CTZLL:
+      case BUILT_IN_FFS:
+      case BUILT_IN_FFSIMAX:
+      case BUILT_IN_FFSL:
+      case BUILT_IN_FFSLL:
+      case BUILT_IN_IMAXABS:
+      case BUILT_IN_FINITE:
+      case BUILT_IN_FINITEF:
+      case BUILT_IN_FINITEL:
+      case BUILT_IN_FINITED32:
+      case BUILT_IN_FINITED64:
+      case BUILT_IN_FINITED128:
+      case BUILT_IN_FPCLASSIFY:
+      case BUILT_IN_ISFINITE:
+      case BUILT_IN_ISINF_SIGN:
+      case BUILT_IN_ISINF:
+      case BUILT_IN_ISINFF:
+      case BUILT_IN_ISINFL:
+      case BUILT_IN_ISINFD32:
+      case BUILT_IN_ISINFD64:
+      case BUILT_IN_ISINFD128:
+      case BUILT_IN_ISNAN:
+      case BUILT_IN_ISNANF:
+      case BUILT_IN_ISNANL:
+      case BUILT_IN_ISNAND32:
+      case BUILT_IN_ISNAND64:
+      case BUILT_IN_ISNAND128:
+      case BUILT_IN_ISNORMAL:
+      case BUILT_IN_ISGREATER:
+      case BUILT_IN_ISGREATEREQUAL:
+      case BUILT_IN_ISLESS:
+      case BUILT_IN_ISLESSEQUAL:
+      case BUILT_IN_ISLESSGREATER:
+      case BUILT_IN_ISUNORDERED:
+      case BUILT_IN_VA_ARG_PACK:
+      case BUILT_IN_VA_ARG_PACK_LEN:
+      case BUILT_IN_VA_COPY:
+      case BUILT_IN_TRAP:
+      case BUILT_IN_SAVEREGS:
+      case BUILT_IN_POPCOUNTL:
+      case BUILT_IN_POPCOUNTLL:
+      case BUILT_IN_POPCOUNTIMAX:
+      case BUILT_IN_POPCOUNT:
+      case BUILT_IN_PARITYL:
+      case BUILT_IN_PARITYLL:
+      case BUILT_IN_PARITYIMAX:
+      case BUILT_IN_PARITY:
+      case BUILT_IN_LABS:
+      case BUILT_IN_LLABS:
+      case BUILT_IN_PREFETCH:
+	return true;
+
+      default:
+	return is_simple_builtin (decl);
+      }
+
+  return false;
+}
+

gcc/cfgloop.h

@@ -627,13 +627,14 @@ fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
 /* The properties of the target.  */
 
 extern unsigned target_avail_regs;
+extern unsigned target_clobbered_regs;
 extern unsigned target_res_regs;
 extern unsigned target_reg_cost [2];
 extern unsigned target_spill_cost [2];
 
 /* Register pressure estimation for induction variable optimizations & loop
    invariant motion.  */
-extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool);
+extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool, bool);
 extern void init_set_costs (void);
 
 /* Loop optimizer initialization.  */

gcc/cfgloopanal.c

@@ -320,6 +320,8 @@ seq_cost (const_rtx seq, bool speed)
 /* The properties of the target.  */
 
 unsigned target_avail_regs;	/* Number of available registers.  */
+unsigned target_clobbered_regs; /* Number of available registers that are
+				   call-clobbered.  */
 unsigned target_res_regs;	/* Number of registers reserved for temporary
 				   expressions.  */
 unsigned target_reg_cost[2];	/* The cost for register when there still
@@ -342,10 +344,15 @@ init_set_costs (void)
   unsigned i;
 
   target_avail_regs = 0;
+  target_clobbered_regs = 0;
   for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
     if (TEST_HARD_REG_BIT (reg_class_contents[GENERAL_REGS], i)
 	&& !fixed_regs[i])
-      target_avail_regs++;
+      {
+	target_avail_regs++;
+	if (call_used_regs[i])
+	  target_clobbered_regs++;
+      }
 
   target_res_regs = 3;
 
@@ -379,20 +386,29 @@ init_set_costs (void)
 
 /* Estimates cost of increased register pressure caused by making N_NEW new
    registers live around the loop.  N_OLD is the number of registers live
-   around the loop.  */
+   around the loop.  If CALL_P is true, also take into account that
+   call-used registers may be clobbered in the loop body, reducing the
+   number of available registers before we spill.  */
 
 unsigned
-estimate_reg_pressure_cost (unsigned n_new, unsigned n_old, bool speed)
+estimate_reg_pressure_cost (unsigned n_new, unsigned n_old, bool speed,
+			    bool call_p)
 {
   unsigned cost;
   unsigned regs_needed = n_new + n_old;
+  unsigned available_regs = target_avail_regs;
+
+  /* If there is a call in the loop body, the call-clobbered registers
+     are not available for loop invariants.  */
+  if (call_p)
+    available_regs = available_regs - target_clobbered_regs;
 
   /* If we have enough registers, we should use them and not restrict
      the transformations unnecessarily.  */
-  if (regs_needed + target_res_regs <= target_avail_regs)
+  if (regs_needed + target_res_regs <= available_regs)
     return 0;
 
-  if (regs_needed <= target_avail_regs)
+  if (regs_needed <= available_regs)
     /* If we are close to running out of registers, try to preserve
        them.  */
     cost = target_reg_cost [speed] * n_new;

gcc/loop-invariant.c

@@ -1173,11 +1173,13 @@ get_inv_cost (struct invariant *inv, int *comp_cost, unsigned *regs_needed)
 /* Calculates gain for eliminating invariant INV.  REGS_USED is the number
    of registers used in the loop, NEW_REGS is the number of new variables
    already added due to the invariant motion.  The number of registers needed
-   for it is stored in *REGS_NEEDED.  */
+   for it is stored in *REGS_NEEDED.  SPEED and CALL_P are flags passed
+   through to estimate_reg_pressure_cost. */
 
 static int
 gain_for_invariant (struct invariant *inv, unsigned *regs_needed,
-		    unsigned *new_regs, unsigned regs_used, bool speed)
+		    unsigned *new_regs, unsigned regs_used,
+		    bool speed, bool call_p)
 {
   int comp_cost, size_cost;
 
@@ -1188,9 +1190,9 @@ gain_for_invariant (struct invariant *inv, unsigned *regs_needed,
   if (! flag_ira_loop_pressure)
     {
       size_cost = (estimate_reg_pressure_cost (new_regs[0] + regs_needed[0],
-					       regs_used, speed)
+					       regs_used, speed, call_p)
 		   - estimate_reg_pressure_cost (new_regs[0],
-						 regs_used, speed));
+						 regs_used, speed, call_p));
     }
   else
     {
@@ -1245,7 +1247,8 @@ gain_for_invariant (struct invariant *inv, unsigned *regs_needed,
 
 static int
 best_gain_for_invariant (struct invariant **best, unsigned *regs_needed,
-			 unsigned *new_regs, unsigned regs_used, bool speed)
+			 unsigned *new_regs, unsigned regs_used,
+			 bool speed, bool call_p)
 {
   struct invariant *inv;
   int i, gain = 0, again;
@@ -1261,7 +1264,7 @@ best_gain_for_invariant (struct invariant **best, unsigned *regs_needed,
 	continue;
 
       again = gain_for_invariant (inv, aregs_needed, new_regs, regs_used,
-      				  speed);
+      				  speed, call_p);
       if (again > gain)
 	{
 	  gain = again;
@@ -1314,7 +1317,7 @@ set_move_mark (unsigned invno, int gain)
 /* Determines which invariants to move.  */
 
 static void
-find_invariants_to_move (bool speed)
+find_invariants_to_move (bool speed, bool call_p)
 {
   int gain;
   unsigned i, regs_used, regs_needed[N_REG_CLASSES], new_regs[N_REG_CLASSES];
@@ -1353,7 +1356,8 @@ find_invariants_to_move (bool speed)
 	new_regs[ira_reg_class_cover[i]] = 0;
     }
   while ((gain = best_gain_for_invariant (&inv, regs_needed,
-					  new_regs, regs_used, speed)) > 0)
+					  new_regs, regs_used,
+					  speed, call_p)) > 0)
     {
       set_move_mark (inv->invno, gain);
       if (! flag_ira_loop_pressure)
@@ -1573,7 +1577,8 @@ move_single_loop_invariants (struct loop *loop)
   init_inv_motion_data ();
 
   find_invariants (loop);
-  find_invariants_to_move (optimize_loop_for_speed_p (loop));
+  find_invariants_to_move (optimize_loop_for_speed_p (loop),
+			   LOOP_DATA (loop)->has_call);
   move_invariants (loop);
 
   free_inv_motion_data ();

gcc/tree-inline.c

@@ -3478,105 +3478,13 @@ estimate_num_insns (gimple stmt, eni_weights *weights)
 	if (POINTER_TYPE_P (funtype))
 	  funtype = TREE_TYPE (funtype);
 
-	if (decl && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_MD)
+	if (is_simple_builtin (decl))
+	  return 0;
+	else if (is_inexpensive_builtin (decl))
 	  cost = weights->target_builtin_call_cost;
 	else
 	  cost = weights->call_cost;
 
-	if (decl && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
-	  switch (DECL_FUNCTION_CODE (decl))
-	    {
-	    /* Builtins that expand to constants.  */
-	    case BUILT_IN_CONSTANT_P:
-	    case BUILT_IN_EXPECT:
-	    case BUILT_IN_OBJECT_SIZE:
-	    case BUILT_IN_UNREACHABLE:
-	    /* Simple register moves or loads from stack.  */
-	    case BUILT_IN_RETURN_ADDRESS:
-	    case BUILT_IN_EXTRACT_RETURN_ADDR:
-	    case BUILT_IN_FROB_RETURN_ADDR:
-	    case BUILT_IN_RETURN:
-	    case BUILT_IN_AGGREGATE_INCOMING_ADDRESS:
-	    case BUILT_IN_FRAME_ADDRESS:
-	    case BUILT_IN_VA_END:
-	    case BUILT_IN_STACK_SAVE:
-	    case BUILT_IN_STACK_RESTORE:
-	    /* Exception state returns or moves registers around.  */
-	    case BUILT_IN_EH_FILTER:
-	    case BUILT_IN_EH_POINTER:
-	    case BUILT_IN_EH_COPY_VALUES:
-	      return 0;
-
-	    /* builtins that are not expensive (that is they are most probably
-	       expanded inline into resonably simple code).  */
-	    case BUILT_IN_ABS:
-	    case BUILT_IN_ALLOCA:
-	    case BUILT_IN_BSWAP32:
-	    case BUILT_IN_BSWAP64:
-	    case BUILT_IN_CLZ:
-	    case BUILT_IN_CLZIMAX:
-	    case BUILT_IN_CLZL:
-	    case BUILT_IN_CLZLL:
-	    case BUILT_IN_CTZ:
-	    case BUILT_IN_CTZIMAX:
-	    case BUILT_IN_CTZL:
-	    case BUILT_IN_CTZLL:
-	    case BUILT_IN_FFS:
-	    case BUILT_IN_FFSIMAX:
-	    case BUILT_IN_FFSL:
-	    case BUILT_IN_FFSLL:
-	    case BUILT_IN_IMAXABS:
-	    case BUILT_IN_FINITE:
-	    case BUILT_IN_FINITEF:
-	    case BUILT_IN_FINITEL:
-	    case BUILT_IN_FINITED32:
-	    case BUILT_IN_FINITED64:
-	    case BUILT_IN_FINITED128:
-	    case BUILT_IN_FPCLASSIFY:
-	    case BUILT_IN_ISFINITE:
-	    case BUILT_IN_ISINF_SIGN:
-	    case BUILT_IN_ISINF:
-	    case BUILT_IN_ISINFF:
-	    case BUILT_IN_ISINFL:
-	    case BUILT_IN_ISINFD32:
-	    case BUILT_IN_ISINFD64:
-	    case BUILT_IN_ISINFD128:
-	    case BUILT_IN_ISNAN:
-	    case BUILT_IN_ISNANF:
-	    case BUILT_IN_ISNANL:
-	    case BUILT_IN_ISNAND32:
-	    case BUILT_IN_ISNAND64:
-	    case BUILT_IN_ISNAND128:
-	    case BUILT_IN_ISNORMAL:
-	    case BUILT_IN_ISGREATER:
-	    case BUILT_IN_ISGREATEREQUAL:
-	    case BUILT_IN_ISLESS:
-	    case BUILT_IN_ISLESSEQUAL:
-	    case BUILT_IN_ISLESSGREATER:
-	    case BUILT_IN_ISUNORDERED:
-	    case BUILT_IN_VA_ARG_PACK:
-	    case BUILT_IN_VA_ARG_PACK_LEN:
-	    case BUILT_IN_VA_COPY:
-	    case BUILT_IN_TRAP:
-	    case BUILT_IN_SAVEREGS:
-	    case BUILT_IN_POPCOUNTL:
-	    case BUILT_IN_POPCOUNTLL:
-	    case BUILT_IN_POPCOUNTIMAX:
-	    case BUILT_IN_POPCOUNT:
-	    case BUILT_IN_PARITYL:
-	    case BUILT_IN_PARITYLL:
-	    case BUILT_IN_PARITYIMAX:
-	    case BUILT_IN_PARITY:
-	    case BUILT_IN_LABS:
-	    case BUILT_IN_LLABS:
-	    case BUILT_IN_PREFETCH:
-	      cost = weights->target_builtin_call_cost;
-	      break;
-
-	    default:
-	      break;
-	    }
-
 	if (decl)
 	  funtype = TREE_TYPE (decl);
 

gcc/tree-ssa-loop-ivopts.c

@@ -260,6 +260,9 @@ struct ivopts_data
 
   /* Are we optimizing for speed?  */
   bool speed;
+
+  /* Whether the loop body includes any function calls.  */
+  bool body_includes_call;
 };
 
 /* An assignment of iv candidates to uses.  */
@@ -4431,7 +4434,8 @@ ivopts_global_cost_for_size (struct ivopts_data *data, unsigned size)
 {
   /* We add size to the cost, so that we prefer eliminating ivs
      if possible.  */
-  return size + estimate_reg_pressure_cost (size, data->regs_used, data->speed);
+  return size + estimate_reg_pressure_cost (size, data->regs_used, data->speed,
+					    data->body_includes_call);
 }
 
 /* For each size of the induction variable set determine the penalty.  */
@@ -4450,6 +4454,7 @@ determine_set_costs (struct ivopts_data *data)
     {
       fprintf (dump_file, "Global costs:\n");
       fprintf (dump_file, "  target_avail_regs %d\n", target_avail_regs);
+      fprintf (dump_file, "  target_clobbered_regs %d\n", target_clobbered_regs);
       fprintf (dump_file, "  target_reg_cost %d\n", target_reg_cost[data->speed]);
       fprintf (dump_file, "  target_spill_cost %d\n", target_spill_cost[data->speed]);
     }
@@ -5859,6 +5864,25 @@ tree_ssa_iv_optimize_finalize (struct ivopts_data *data)
   VEC_free (iv_cand_p, heap, data->iv_candidates);
 }
 
+/* Returns true if the loop body BODY includes any function calls.  */
+
+static bool
+loop_body_includes_call (basic_block *body, unsigned num_nodes)
+{
+  gimple_stmt_iterator gsi;
+  unsigned i;
+
+  for (i = 0; i < num_nodes; i++)
+    for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi); gsi_next (&gsi))
+      {
+	gimple stmt = gsi_stmt (gsi);
+	if (is_gimple_call (stmt)
+	    && !is_inexpensive_builtin (gimple_call_fndecl (stmt)))
+	  return true;
+      }
+  return false;
+}
+
 /* Optimizes the LOOP.  Returns true if anything changed.  */
 
 static bool
@@ -5890,6 +5914,7 @@ tree_ssa_iv_optimize_loop (struct ivopts_data *data, struct loop *loop)
     }
 
   body = get_loop_body (loop);
+  data->body_includes_call = loop_body_includes_call (body, loop->num_nodes);
   renumber_gimple_stmt_uids_in_blocks (body, loop->num_nodes);
   free (body);
 

gcc/tree.h

@@ -5046,6 +5046,8 @@ extern tree build_range_check (location_t, tree, tree, int, tree, tree);
 extern bool merge_ranges (int *, tree *, tree *, int, tree, tree, int,
 			  tree, tree);
 extern void set_builtin_user_assembler_name (tree decl, const char *asmspec);
+extern bool is_simple_builtin (tree);
+extern bool is_inexpensive_builtin (tree);
 
 /* In convert.c */
 extern tree strip_float_extensions (tree);