[PATCH 8/9] Negative numbers added for sreal class.

[mliska <mliska at suse dot cz>]

gcc/ChangeLog:

2014-11-13  Martin Liska  <mliska@suse.cz>

	* predict.c (propagate_freq): More elegant sreal API is used.
	(estimate_bb_frequencies): New static constants defined by sreal
	replace precomputed ones.
	* sreal.c (sreal::normalize): New function.
	(sreal::to_int): Likewise.
	(sreal::operator+): Likewise.
	(sreal::operator-): Likewise.
	* sreal.h: Definition of new functions added.
---
 gcc/predict.c | 30 +++++++++++-------------
 gcc/sreal.c   | 56 ++++++++++++++++++++++++++++++++++++--------
 gcc/sreal.h   | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 3 files changed, 126 insertions(+), 35 deletions(-)

diff --git a/gcc/predict.c b/gcc/predict.c
index 0215e91..0f640f5 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -82,7 +82,7 @@ along with GCC; see the file COPYING3.  If not see
 
 /* real constants: 0, 1, 1-1/REG_BR_PROB_BASE, REG_BR_PROB_BASE,
 		   1/REG_BR_PROB_BASE, 0.5, BB_FREQ_MAX.  */
-static sreal real_zero, real_one, real_almost_one, real_br_prob_base,
+static sreal real_almost_one, real_br_prob_base,
 	     real_inv_br_prob_base, real_one_half, real_bb_freq_max;
 
 static void combine_predictions_for_insn (rtx_insn *, basic_block);
@@ -2528,13 +2528,13 @@ propagate_freq (basic_block head, bitmap tovisit)
 	bb->count = bb->frequency = 0;
     }
 
-  BLOCK_INFO (head)->frequency = real_one;
+  BLOCK_INFO (head)->frequency = sreal::one ();
   last = head;
   for (bb = head; bb; bb = nextbb)
     {
       edge_iterator ei;
-      sreal cyclic_probability = real_zero;
-      sreal frequency = real_zero;
+      sreal cyclic_probability = sreal::zero ();
+      sreal frequency = sreal::zero ();
 
       nextbb = BLOCK_INFO (bb)->next;
       BLOCK_INFO (bb)->next = NULL;
@@ -2559,13 +2559,13 @@ propagate_freq (basic_block head, bitmap tovisit)
 				  * BLOCK_INFO (e->src)->frequency /
 				  REG_BR_PROB_BASE);  */
 
-		sreal tmp (e->probability, 0);
+		sreal tmp = e->probability;
 		tmp *= BLOCK_INFO (e->src)->frequency;
 		tmp *= real_inv_br_prob_base;
 		frequency += tmp;
 	      }
 
-	  if (cyclic_probability == real_zero)
+	  if (cyclic_probability == sreal::zero ())
 	    {
 	      BLOCK_INFO (bb)->frequency = frequency;
 	    }
@@ -2577,7 +2577,7 @@ propagate_freq (basic_block head, bitmap tovisit)
 	      /* BLOCK_INFO (bb)->frequency = frequency
 					      / (1 - cyclic_probability) */
 
-	      cyclic_probability = real_one - cyclic_probability;
+	      cyclic_probability = sreal::one () - cyclic_probability;
 	      BLOCK_INFO (bb)->frequency = frequency / cyclic_probability;
 	    }
 	}
@@ -2591,7 +2591,7 @@ propagate_freq (basic_block head, bitmap tovisit)
 	     = ((e->probability * BLOCK_INFO (bb)->frequency)
 	     / REG_BR_PROB_BASE); */
 
-	  sreal tmp (e->probability, 0);
+	  sreal tmp = e->probability;
 	  tmp *= BLOCK_INFO (bb)->frequency;
 	  EDGE_INFO (e)->back_edge_prob = tmp * real_inv_br_prob_base;
 	}
@@ -2873,13 +2873,11 @@ estimate_bb_frequencies (bool force)
       if (!real_values_initialized)
         {
 	  real_values_initialized = 1;
-	  real_zero = sreal (0, 0);
-	  real_one = sreal (1, 0);
-	  real_br_prob_base = sreal (REG_BR_PROB_BASE, 0);
-	  real_bb_freq_max = sreal (BB_FREQ_MAX, 0);
+	  real_br_prob_base = REG_BR_PROB_BASE;
+	  real_bb_freq_max = BB_FREQ_MAX;
 	  real_one_half = sreal (1, -1);
-	  real_inv_br_prob_base = real_one / real_br_prob_base;
-	  real_almost_one = real_one - real_inv_br_prob_base;
+	  real_inv_br_prob_base = sreal::one () / real_br_prob_base;
+	  real_almost_one = sreal::one () - real_inv_br_prob_base;
 	}
 
       mark_dfs_back_edges ();
@@ -2897,7 +2895,7 @@ estimate_bb_frequencies (bool force)
 
 	  FOR_EACH_EDGE (e, ei, bb->succs)
 	    {
-	      EDGE_INFO (e)->back_edge_prob = sreal (e->probability, 0);
+	      EDGE_INFO (e)->back_edge_prob = e->probability;
 	      EDGE_INFO (e)->back_edge_prob *= real_inv_br_prob_base;
 	    }
 	}
@@ -2906,7 +2904,7 @@ estimate_bb_frequencies (bool force)
          to outermost to examine frequencies for back edges.  */
       estimate_loops ();
 
-      freq_max = real_zero;
+      freq_max = sreal::zero ();
       FOR_EACH_BB_FN (bb, cfun)
 	if (freq_max < BLOCK_INFO (bb)->frequency)
 	  freq_max = BLOCK_INFO (bb)->frequency;
diff --git a/gcc/sreal.c b/gcc/sreal.c
index 3f5456a..89b9c4d 100644
--- a/gcc/sreal.c
+++ b/gcc/sreal.c
@@ -1,4 +1,4 @@
-/* Simple data type for positive real numbers for the GNU compiler.
+/* Simple data type for real numbers for the GNU compiler.
    Copyright (C) 2002-2014 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
-/* This library supports positive real numbers and 0;
+/* This library supports real numbers;
    inf and nan are NOT supported.
    It is written to be simple and fast.
 
@@ -102,6 +102,7 @@ sreal::normalize ()
 {
   if (m_sig == 0)
     {
+      m_negative = 0;
       m_exp = -SREAL_MAX_EXP;
     }
   else if (m_sig < SREAL_MIN_SIG)
@@ -153,15 +154,17 @@ sreal::normalize ()
 int64_t
 sreal::to_int () const
 {
+  int64_t sign = m_negative ? -1 : 1;
+
   if (m_exp <= -SREAL_BITS)
     return 0;
   if (m_exp >= SREAL_PART_BITS)
-    return INTTYPE_MAXIMUM (int64_t);
+    return sign * INTTYPE_MAXIMUM (int64_t);
   if (m_exp > 0)
-    return m_sig << m_exp;
+    return sign * (m_sig << m_exp);
   if (m_exp < 0)
-    return m_sig >> -m_exp;
-  return m_sig;
+    return sign * (m_sig >> -m_exp);
+  return sign * m_sig;
 }
 
 /* Return *this + other.  */
@@ -169,9 +172,19 @@ sreal::to_int () const
 sreal
 sreal::operator+ (const sreal &other) const
 {
+  const sreal *a_p = this, *b_p = &other, *bb;
+
+  if (m_negative && !other.m_negative)
+    return other + *a_p;
+
+  if (!m_negative && other.m_negative)
+    return *a_p - -other;
+
+  gcc_assert (m_negative == other.m_negative);
+
   int dexp;
   sreal tmp, r;
-const sreal *a_p = this, *b_p = &other, *bb;
+  r.m_negative = a_p->m_negative;
 
   if (*a_p < *b_p)
     {
@@ -211,10 +224,30 @@ sreal::operator- (const sreal &other) const
   int dexp;
   sreal tmp, r;
   const sreal *bb;
+  const sreal *a_p = this;
+
+  /* -a - b => -a + (-b).  */
+  if (m_negative && !other.m_negative)
+    return *a_p + -other;
 
-  gcc_assert (*this >= other);
+  /* a - (-b) => a + b.  */
+  if (!m_negative && other.m_negative)
+    return *a_p + -other;
+
+  gcc_assert (m_negative == other.m_negative);
+
+  /* We want to substract a smaller number from bigger
+    for nonegative numbers.  */
+  if (!m_negative && *this < other)
+    return -(other - *this);
+
+  /* Example: -2 - (-3) => 3 - 2 */
+  if (m_negative && *this > other)
+    return -other - -(*this);
 
   dexp = m_exp - other.m_exp;
+
+  r.m_negative = m_negative;
   r.m_exp = m_exp;
   if (dexp > SREAL_BITS)
     {
@@ -240,7 +273,7 @@ sreal::operator- (const sreal &other) const
 sreal
 sreal::operator* (const sreal &other) const
 {
-sreal r;
+  sreal r;
   if (m_sig < SREAL_MIN_SIG || other.m_sig < SREAL_MIN_SIG)
     {
       r.m_sig = 0;
@@ -252,6 +285,8 @@ sreal r;
       r.m_exp = m_exp + other.m_exp;
       r.normalize ();
     }
+
+  r.m_negative = m_negative ^ other.m_negative;
   return r;
 }
 
@@ -261,9 +296,10 @@ sreal
 sreal::operator/ (const sreal &other) const
 {
   gcc_assert (other.m_sig != 0);
-sreal r;
+  sreal r;
   r.m_sig = (m_sig << SREAL_PART_BITS) / other.m_sig;
   r.m_exp = m_exp - other.m_exp - SREAL_PART_BITS;
+  r.m_negative = m_negative ^ other.m_negative;
   r.normalize ();
   return r;
 }
diff --git a/gcc/sreal.h b/gcc/sreal.h
index 461e28b..bfed3c7 100644
--- a/gcc/sreal.h
+++ b/gcc/sreal.h
@@ -1,4 +1,4 @@
-/* Definitions for simple data type for positive real numbers.
+/* Definitions for simple data type for real numbers.
    Copyright (C) 2002-2014 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -25,7 +25,7 @@ along with GCC; see the file COPYING3.  If not see
 
 #define SREAL_MIN_SIG ((uint64_t) 1 << (SREAL_PART_BITS - 1))
 #define SREAL_MAX_SIG (((uint64_t) 1 << SREAL_PART_BITS) - 1)
-#define SREAL_MAX_EXP (INT_MAX / 4)
+#define SREAL_MAX_EXP (INT_MAX / 8)
 
 #define SREAL_BITS SREAL_PART_BITS
 
@@ -34,10 +34,21 @@ class sreal
 {
 public:
   /* Construct an uninitialized sreal.  */
-  sreal () : m_sig (-1), m_exp (-1) {}
+  sreal () : m_sig (-1), m_exp (-1), m_negative (0) {}
 
   /* Construct a sreal.  */
-  sreal (uint64_t sig, int exp) : m_sig (sig), m_exp (exp) { normalize (); }
+  sreal (int64_t sig, int exp = 0) : m_exp (exp)
+  {
+    m_negative = sig < 0;
+
+    // TODO: speed up
+    if (sig < 0)
+      sig = -sig;
+
+    m_sig = (uint64_t) sig;
+
+    normalize ();
+  }
 
   void dump (FILE *) const;
   int64_t to_int () const;
@@ -49,13 +60,58 @@ public:
 
   bool operator< (const sreal &other) const
   {
-    return m_exp < other.m_exp
+    if (m_negative != other.m_negative)
+      return m_negative > other.m_negative;
+
+    bool r = m_exp < other.m_exp
       || (m_exp == other.m_exp && m_sig < other.m_sig);
+
+    return m_negative ? !r : r;
   }
 
   bool operator== (const sreal &other) const
   {
-    return m_exp == other.m_exp && m_sig == other.m_sig;
+    return m_exp == other.m_exp && m_sig == other.m_sig
+		    && m_negative == other.m_negative;
+  }
+
+  sreal operator- () const
+  {
+    if (m_sig == 0)
+      return *this;
+
+    sreal tmp = *this;
+    tmp.m_negative = !tmp.m_negative;
+
+    return tmp;
+  }
+
+  sreal shift (int sig) const
+  {
+    sreal tmp = *this;
+    tmp.m_sig += sig;
+
+    return tmp;
+  }
+
+  /* Return zero constant.  */
+  inline static sreal zero ()
+  {
+    static const sreal zero = sreal (0);
+    return zero;
+  }
+
+  /* Return one constant.  */
+  inline static sreal one ()
+  {
+    static const sreal one = sreal (1);
+    return one;
+  }
+
+  /* Global minimum sreal can hold.  */
+  inline static sreal min ()
+  {
+    return sreal (LONG_MIN, 0);
   }
 
 private:
@@ -63,7 +119,8 @@ private:
   void shift_right (int amount);
 
   uint64_t m_sig;		/* Significant.  */
-  signed int m_exp;			/* Exponent.  */
+  signed int m_exp: 31;		/* Exponent.  */
+  unsigned int m_negative: 1;	/* Negative sign.  */
 };
 
 extern void debug (sreal &ref);
@@ -76,12 +133,12 @@ inline sreal &operator+= (sreal &a, const sreal &b)
 
 inline sreal &operator-= (sreal &a, const sreal &b)
 {
-return a = a - b;
+  return a = a - b;
 }
 
 inline sreal &operator/= (sreal &a, const sreal &b)
 {
-return a = a / b;
+  return a = a / b;
 }
 
 inline sreal &operator*= (sreal &a, const sreal &b)
-- 
2.1.2