value-prof.c: New.

	* value-prof.c: New.
	* value-prof.h: New.

From-SVN: r68521

gcc/value-prof.c

+/* Transformations based on profile information for values.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "expr.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "value-prof.h"
+#include "output.h"
+#include "flags.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "optabs.h"
+
+/* In this file value profile based optimizations will be placed (none are
+   here just now, but they are hopefully coming soon).
+
+   Every such optimization should add its requirements for profiled values to
+   insn_values_to_profile function.  This function is called from branch_prob
+   in profile.c and the requested values are instrumented by it in the first
+   compilation with -fprofile-arcs.  The optimization may then read the
+   gathered data in the second compilation with -fbranch-probablities (the
+   description of an exact way how to do it will be added here once the
+   code responsible for reading of the data is merged).  */
+
+static void insn_values_to_profile (rtx, unsigned *, struct histogram_value **);
+
+/* Release the list of VALUES of length N_VALUES for that we want to measure
+   histograms.  */
+void
+free_profiled_values (unsigned n_values ATTRIBUTE_UNUSED,
+		      struct histogram_value *values)
+{
+  free (values);
+}
+
+/* Find values inside INSN for that we want to measure histograms and adds
+   them to list VALUES (increasing the record of its length in N_VALUES).  */
+static void
+insn_values_to_profile (rtx insn ATTRIBUTE_UNUSED,
+			unsigned *n_values ATTRIBUTE_UNUSED,
+			struct histogram_value **values ATTRIBUTE_UNUSED)
+{
+}
+
+/* Find list of values for that we want to measure histograms.  */
+void
+find_values_to_profile (unsigned *n_values, struct histogram_value **values)
+{
+  rtx insn;
+  unsigned i;
+
+  *n_values = 0;
+  *values = NULL;
+  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+    insn_values_to_profile (insn, n_values, values);
+
+  for (i = 0; i < *n_values; i++)
+    {
+      switch ((*values)[i].type)
+	{
+	case HIST_TYPE_INTERVAL:
+	  (*values)[i].n_counters = (*values)[i].hdata.intvl.steps +
+		  ((*values)[i].hdata.intvl.may_be_less ? 1 : 0) +
+		  ((*values)[i].hdata.intvl.may_be_more ? 1 : 0);
+	  break;
+
+	case HIST_TYPE_POW2:
+	  (*values)[i].n_counters = GET_MODE_BITSIZE ((*values)[i].mode) +
+		  ((*values)[i].hdata.pow2.may_be_other ? 1 : 0);
+	  break;
+
+	case HIST_TYPE_SINGLE_VALUE:
+	  (*values)[i].n_counters = 3;
+	  break;
+
+	case HIST_TYPE_CONST_DELTA:
+	  (*values)[i].n_counters = 4;
+	  break;
+
+	default:
+	  abort ();
+	}
+    }
+}

gcc/value-prof.h

+/* Definitions for transformations based on profile information for values.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.  */
+
+/* Supported histogram types.  */
+enum hist_type
+{
+  HIST_TYPE_INTERVAL,	/* Measures histogram of values inside a specified
+			   interval.  */
+  HIST_TYPE_POW2,	/* Histogram of power of 2 values.  */
+  HIST_TYPE_SINGLE_VALUE, /* Tries to identify the value that is (almost)
+			   always constant.  */
+  HIST_TYPE_CONST_DELTA	/* Tries to identify the (almost) always constant
+			   difference between two evaluations of a value.  */
+};
+
+/* The value to measure.  */
+struct histogram_value
+{
+  rtx value;		/* The value to profile.  */
+  enum machine_mode mode; /* And its mode.  */
+  rtx seq;		/* Insns requiered to count the profiled value.  */
+  rtx insn;		/* Insn before that to measure.  */
+  enum hist_type type;	/* Type of information to measure.  */
+  unsigned n_counters;	/* Number of requiered counters.  */
+  union
+    {
+      struct
+	{
+	  int int_start;	/* First value in interval.  */
+	  int steps;		/* Number of values in it.  */
+	  int may_be_less;	/* May the value be below?  */
+	  int may_be_more;	/* Or above.  */
+	} intvl;	/* Interval histogram data.  */
+      struct
+	{
+	  int may_be_other;	/* If the value may be non-positive or not 2^k.  */
+	} pow2;		/* Power of 2 histogram data.  */
+    } hdata;		/* Profiled information specific data.  */
+};
+
+extern void find_values_to_profile (unsigned *, struct histogram_value **);
+extern void free_profiled_values (unsigned, struct histogram_value *);