Segher Boessenkool <segher@koffie.nl>

	* predict.c (real_inv_br_prob_base): New variable.
	(propagate_freq): Use multiply by reciprocal instead of
	division.  Don't divide by 1.0 at all.
	(estimate_bb_frequencies): Similar.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@61326 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ab9add8..5d907b1 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2003-01-15  Segher Boessenkool  <segher@koffie.nl>
+
+       * predict.c (real_inv_br_prob_base): New variable.
+       (propagate_freq): Use multiply by reciprocal instead of
+       division.  Don't divide by 1.0 at all.
+       (estimate_bb_frequencies): Similar.
+
 2003-01-15  Alexandre Oliva  <aoliva@redhat.com>
 
        * configure.in (libgcc_visibility): Force disabled on IRIX 6 too.

diff --git a/gcc/predict.c b/gcc/predict.c
index 3f3e2fc..4ca71d3 100644 (file)
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -53,10 +53,10 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #include "target.h"
 #include "loop.h"
 
-/* real constants: 0, 1, 1-1/REG_BR_PROB_BASE, REG_BR_PROB_BASE, 0.5,
-                   REAL_BB_FREQ_MAX.  */
+/* 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 REAL_VALUE_TYPE real_zero, real_one, real_almost_one, real_br_prob_base,
-                      real_one_half, real_bb_freq_max;
+                      real_inv_br_prob_base, real_one_half, real_bb_freq_max;
 
 /* Random guesstimation given names.  */
 #define PROB_VERY_UNLIKELY     (REG_BR_PROB_BASE / 10 - 1)
@@ -988,20 +988,25 @@ propagate_freq (loop)
                                     TYPE_MODE (double_type_node));
                REAL_ARITHMETIC (tmp, MULT_EXPR, tmp,
                                 BLOCK_INFO (e->src)->frequency);
-               REAL_ARITHMETIC (tmp, RDIV_EXPR, tmp, real_br_prob_base);
+               REAL_ARITHMETIC (tmp, MULT_EXPR, tmp, real_inv_br_prob_base);
                REAL_ARITHMETIC (frequency, PLUS_EXPR, frequency, tmp);
              }
 
-         if (REAL_VALUES_LESS (real_almost_one, cyclic_probability))
-           memcpy (&cyclic_probability, &real_almost_one, sizeof (real_zero));
+         if (REAL_VALUES_IDENTICAL (cyclic_probability, real_zero))
+           memcpy (&BLOCK_INFO (bb)->frequency, &frequency, sizeof (frequency));
+         else
+           {
+             if (REAL_VALUES_LESS (real_almost_one, cyclic_probability))
+               memcpy (&cyclic_probability, &real_almost_one, sizeof (real_zero));
 
-         /* BLOCK_INFO (bb)->frequency = frequency / (1 - cyclic_probability)
-          */
+             /* BLOCK_INFO (bb)->frequency = frequency / (1 - cyclic_probability)
+              */
 
-         REAL_ARITHMETIC (cyclic_probability, MINUS_EXPR, real_one,
+             REAL_ARITHMETIC (cyclic_probability, MINUS_EXPR, real_one,
                           cyclic_probability);
-         REAL_ARITHMETIC (BLOCK_INFO (bb)->frequency,
-                          RDIV_EXPR, frequency, cyclic_probability);
+             REAL_ARITHMETIC (BLOCK_INFO (bb)->frequency,
+                              RDIV_EXPR, frequency, cyclic_probability);
+           }
        }
 
       BLOCK_INFO (bb)->tovisit = 0;
@@ -1020,7 +1025,7 @@ propagate_freq (loop)
            REAL_ARITHMETIC (tmp, MULT_EXPR, tmp,
                             BLOCK_INFO (bb)->frequency);
            REAL_ARITHMETIC (EDGE_INFO (e)->back_edge_prob,
-                            RDIV_EXPR, tmp, real_br_prob_base);
+                            MULT_EXPR, tmp, real_inv_br_prob_base);
 
          }
 
@@ -1151,11 +1156,9 @@ estimate_bb_frequencies (loops)
       REAL_VALUE_FROM_INT (real_br_prob_base, REG_BR_PROB_BASE, 0, double_mode);
       REAL_VALUE_FROM_INT (real_bb_freq_max, BB_FREQ_MAX, 0, double_mode);
       REAL_VALUE_FROM_INT (real_one_half, 2, 0, double_mode);
-
       REAL_ARITHMETIC (real_one_half, RDIV_EXPR, real_one, real_one_half);
-
-      REAL_ARITHMETIC (real_almost_one, RDIV_EXPR, real_one, real_br_prob_base);
-      REAL_ARITHMETIC (real_almost_one, MINUS_EXPR, real_one, real_almost_one);
+      REAL_ARITHMETIC (real_inv_br_prob_base, RDIV_EXPR, real_one, real_br_prob_base);
+      REAL_ARITHMETIC (real_almost_one, MINUS_EXPR, real_one, real_inv_br_prob_base);
 
       mark_dfs_back_edges ();
       /* Fill in the probability values in flowgraph based on the REG_BR_PROB
@@ -1199,8 +1202,8 @@ estimate_bb_frequencies (loops)
              REAL_VALUE_FROM_INT (EDGE_INFO (e)->back_edge_prob,
                                   e->probability, 0, double_mode);
              REAL_ARITHMETIC (EDGE_INFO (e)->back_edge_prob,
-                              RDIV_EXPR, EDGE_INFO (e)->back_edge_prob,
-                              real_br_prob_base);
+                              MULT_EXPR, EDGE_INFO (e)->back_edge_prob,
+                              real_inv_br_prob_base);
            }
        }
 
@@ -1215,13 +1218,14 @@ estimate_bb_frequencies (loops)
          memcpy (&freq_max, &BLOCK_INFO (bb)->frequency,
                  sizeof (freq_max));
 
+      REAL_ARITHMETIC (freq_max, RDIV_EXPR, real_bb_freq_max, freq_max);
+
       FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
        {
          REAL_VALUE_TYPE tmp;
 
          REAL_ARITHMETIC (tmp, MULT_EXPR, BLOCK_INFO (bb)->frequency,
-                          real_bb_freq_max);
-         REAL_ARITHMETIC (tmp, RDIV_EXPR, tmp, freq_max);
+                          freq_max);
          REAL_ARITHMETIC (tmp, PLUS_EXPR, tmp, real_one_half);
          bb->frequency = REAL_VALUE_UNSIGNED_FIX (tmp);
        }