IRA: Use minimal cost for hard register movement

This is the 2nd attempt to fix PR90706.  IRA calculates wrong AVR
costs for moving general hard regs of SFmode.  This was the reason for
spilling a pseudo in the PR.  In this patch we use smaller move cost
of hard reg in its natural and operand modes.

        PR rtl-optimization/90706

gcc/ChangeLog:

	* ira-costs.cc: Include print-rtl.h.
	(record_reg_classes, scan_one_insn): Add code to print debug info.
	(record_operand_costs): Find and use smaller cost for hard reg
	move.

gcc/testsuite/ChangeLog:

	* gcc.target/avr/pr90706.c: New.

diff --git a/gcc/ira-costs.cc b/gcc/ira-costs.cc
index 4c28171..c0fdef8 100644 (file)
--- a/gcc/ira-costs.cc
+++ b/gcc/ira-costs.cc
@@ -34,6 +34,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "ira-int.h"
 #include "addresses.h"
 #include "reload.h"
+#include "print-rtl.h"
 
 /* The flags is set up every time when we calculate pseudo register
    classes through function ira_set_pseudo_classes.  */
@@ -503,6 +504,18 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops,
   int insn_allows_mem[MAX_RECOG_OPERANDS];
   move_table *move_in_cost, *move_out_cost;
   short (*mem_cost)[2];
+  const char *p;
+
+  if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+    {
+      fprintf (ira_dump_file, "    Processing insn %u", INSN_UID (insn));
+      if (INSN_CODE (insn) >= 0
+         && (p = get_insn_name (INSN_CODE (insn))) != NULL)
+       fprintf (ira_dump_file, " {%s}", p);
+      fprintf (ira_dump_file, " (freq=%d)\n",
+              REG_FREQ_FROM_BB (BLOCK_FOR_INSN (insn)));
+      dump_insn_slim (ira_dump_file, insn);
+  }
 
   for (i = 0; i < n_ops; i++)
     insn_allows_mem[i] = 0;
@@ -526,6 +539,21 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops,
          continue;
        }
 
+      if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+       {
+         fprintf (ira_dump_file, "      Alt %d:", alt);
+         for (i = 0; i < n_ops; i++)
+           {
+             p = constraints[i];
+             if (*p == '\0')
+               continue;
+             fprintf (ira_dump_file, "  (%d) ", i);
+             for (; *p != '\0' && *p != ',' && *p != '#'; p++)
+               fputc (*p, ira_dump_file);
+           }
+         fprintf (ira_dump_file, "\n");
+       }
+
       for (i = 0; i < n_ops; i++)
        {
          unsigned char c;
@@ -593,12 +621,16 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops,
                     register, this alternative can't be used.  */
 
                  if (classes[j] == NO_REGS)
-                   alt_fail = 1;
-                 /* Otherwise, add to the cost of this alternative
-                    the cost to copy the other operand to the hard
-                    register used for this operand.  */
+                   {
+                     alt_fail = 1;
+                   }
                  else
-                   alt_cost += copy_cost (ops[j], mode, classes[j], 1, NULL);
+                   /* Otherwise, add to the cost of this alternative the cost
+                      to copy the other operand to the hard register used for
+                      this operand.  */
+                   {
+                     alt_cost += copy_cost (ops[j], mode, classes[j], 1, NULL);
+                   }
                }
              else
                {
@@ -1021,18 +1053,45 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops,
       for (i = 0; i < n_ops; i++)
        if (REG_P (ops[i]) && REGNO (ops[i]) >= FIRST_PSEUDO_REGISTER)
          {
+           int old_cost;
+           bool cost_change_p = false;
            struct costs *pp = op_costs[i], *qq = this_op_costs[i];
            int *pp_costs = pp->cost, *qq_costs = qq->cost;
            int scale = 1 + (recog_data.operand_type[i] == OP_INOUT);
            cost_classes_t cost_classes_ptr
              = regno_cost_classes[REGNO (ops[i])];
 
-           pp->mem_cost = MIN (pp->mem_cost,
+           old_cost = pp->mem_cost;
+           pp->mem_cost = MIN (old_cost,
                                (qq->mem_cost + op_cost_add) * scale);
 
+           if (ira_dump_file != NULL && internal_flag_ira_verbose > 5
+               && pp->mem_cost < old_cost)
+             {
+               cost_change_p = true;
+               fprintf (ira_dump_file, "        op %d(r=%u) new costs MEM:%d",
+                        i, REGNO(ops[i]), pp->mem_cost);
+             }
            for (k = cost_classes_ptr->num - 1; k >= 0; k--)
-             pp_costs[k]
-               = MIN (pp_costs[k], (qq_costs[k] + op_cost_add) * scale);
+             {
+               old_cost = pp_costs[k];
+               pp_costs[k]
+                 = MIN (old_cost, (qq_costs[k] + op_cost_add) * scale);
+               if (ira_dump_file != NULL && internal_flag_ira_verbose > 5
+                   && pp_costs[k] < old_cost)
+                 {
+                   if (!cost_change_p)
+                     fprintf (ira_dump_file, "        op %d(r=%u) new costs",
+                              i, REGNO(ops[i]));
+                   cost_change_p = true;
+                   fprintf (ira_dump_file, " %s:%d",
+                            reg_class_names[cost_classes_ptr->classes[k]],
+                            pp_costs[k]);
+                 }
+             }
+           if (ira_dump_file != NULL && internal_flag_ira_verbose > 5
+               && cost_change_p)
+             fprintf (ira_dump_file, "\n");
          }
     }
 
@@ -1307,26 +1366,48 @@ record_operand_costs (rtx_insn *insn, enum reg_class *pref)
              || ((regno = REGNO (dest)) >= FIRST_PSEUDO_REGISTER
                  && (other_regno = REGNO (src)) < FIRST_PSEUDO_REGISTER)))
        {
-         machine_mode mode = GET_MODE (SET_SRC (set));
+         machine_mode mode = GET_MODE (SET_SRC (set)), cost_mode = mode;
+         machine_mode hard_reg_mode = GET_MODE(regno_reg_rtx[other_regno]);
+         poly_int64 pmode_size = GET_MODE_SIZE (mode);
+         poly_int64 phard_reg_mode_size = GET_MODE_SIZE (hard_reg_mode);
+         HOST_WIDE_INT mode_size, hard_reg_mode_size;
          cost_classes_t cost_classes_ptr = regno_cost_classes[regno];
          enum reg_class *cost_classes = cost_classes_ptr->classes;
          reg_class_t rclass, hard_reg_class, bigger_hard_reg_class;
-         int cost, k;
+         int cost_factor = 1, cost, k;
          move_table *move_costs;
          bool dead_p = find_regno_note (insn, REG_DEAD, REGNO (src));
 
-         ira_init_register_move_cost_if_necessary (mode);
-         move_costs = ira_register_move_cost[mode];
          hard_reg_class = REGNO_REG_CLASS (other_regno);
-         bigger_hard_reg_class = ira_pressure_class_translate[hard_reg_class];
-         /* Target code may return any cost for mode which does not
-            fit the hard reg class (e.g. DImode for AREG on
-            i386).  Check this and use a bigger class to get the
-            right cost.  */
-         if (bigger_hard_reg_class != NO_REGS
-             && ! ira_hard_reg_in_set_p (other_regno, mode,
-                                         reg_class_contents[hard_reg_class]))
-           hard_reg_class = bigger_hard_reg_class;
+          bigger_hard_reg_class = ira_pressure_class_translate[hard_reg_class];
+          /* Target code may return any cost for mode which does not fit the
+             hard reg class (e.g. DImode for AREG on i386).  Check this and use
+             a bigger class to get the right cost.  */
+          if (bigger_hard_reg_class != NO_REGS
+              && ! ira_hard_reg_in_set_p (other_regno, mode,
+                                          reg_class_contents[hard_reg_class]))
+            hard_reg_class = bigger_hard_reg_class;
+          ira_init_register_move_cost_if_necessary (mode);
+          ira_init_register_move_cost_if_necessary (hard_reg_mode);
+         /* Use smaller movement cost for natural hard reg mode or its mode as
+            operand.  */
+          if (pmode_size.is_constant (&mode_size)
+              && phard_reg_mode_size.is_constant (&hard_reg_mode_size))
+            {
+             /* Assume we are moving in the natural modes: */
+              cost_factor = mode_size / hard_reg_mode_size;
+              if (mode_size % hard_reg_mode_size != 0)
+               cost_factor++;
+             if (cost_factor
+                 * (ira_register_move_cost
+                    [hard_reg_mode][hard_reg_class][hard_reg_class])
+                 < (ira_register_move_cost
+                    [mode][hard_reg_class][hard_reg_class]))
+               cost_mode = hard_reg_mode;
+             else
+               cost_factor = 1;
+            }
+          move_costs = ira_register_move_cost[cost_mode];
          i = regno == (int) REGNO (src) ? 1 : 0;
          for (k = cost_classes_ptr->num - 1; k >= 0; k--)
            {
@@ -1334,7 +1415,7 @@ record_operand_costs (rtx_insn *insn, enum reg_class *pref)
              cost = (i == 0
                      ? move_costs[hard_reg_class][rclass]
                      : move_costs[rclass][hard_reg_class]);
-             
+             cost *= cost_factor;
              op_costs[i]->cost[k] = cost * frequency;
              /* If this insn is a single set copying operand 1 to
                 operand 0 and one operand is an allocno with the
@@ -1506,12 +1587,24 @@ scan_one_insn (rtx_insn *insn)
 
   record_operand_costs (insn, pref);
 
+  if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+    {
+      const char *p;
+      fprintf (ira_dump_file, "    Final costs after insn %u", INSN_UID (insn));
+      if (INSN_CODE (insn) >= 0
+         && (p = get_insn_name (INSN_CODE (insn))) != NULL)
+       fprintf (ira_dump_file, " {%s}", p);
+      fprintf (ira_dump_file, " (freq=%d)\n",
+              REG_FREQ_FROM_BB (BLOCK_FOR_INSN (insn)));
+      dump_insn_slim (ira_dump_file, insn);
+    }
+
   /* Now add the cost for each operand to the total costs for its
      allocno.  */
   for (i = 0; i < recog_data.n_operands; i++)
     {
       rtx op = recog_data.operand[i];
-      
+
       if (GET_CODE (op) == SUBREG)
        op = SUBREG_REG (op);
       if (REG_P (op) && REGNO (op) >= FIRST_PSEUDO_REGISTER)
@@ -1521,8 +1614,8 @@ scan_one_insn (rtx_insn *insn)
          struct costs *q = op_costs[i];
          int *p_costs = p->cost, *q_costs = q->cost;
          cost_classes_t cost_classes_ptr = regno_cost_classes[regno];
-         int add_cost;
-         
+         int add_cost = 0;
+
          /* If the already accounted for the memory "cost" above, don't
             do so again.  */
          if (!counted_mem)
@@ -1533,6 +1626,11 @@ scan_one_insn (rtx_insn *insn)
              else
                p->mem_cost += add_cost;
            }
+         if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+           {
+             fprintf (ira_dump_file, "        op %d(r=%u) MEM:%d(+%d)",
+                      i, REGNO(op), p->mem_cost, add_cost);
+           }
          for (k = cost_classes_ptr->num - 1; k >= 0; k--)
            {
              add_cost = q_costs[k];
@@ -1540,7 +1638,15 @@ scan_one_insn (rtx_insn *insn)
                p_costs[k] = INT_MAX;
              else
                p_costs[k] += add_cost;
+             if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+               {
+                 fprintf (ira_dump_file, " %s:%d(+%d)",
+                          reg_class_names[cost_classes_ptr->classes[k]],
+                          p_costs[k], add_cost);
+               }
            }
+         if (ira_dump_file != NULL && internal_flag_ira_verbose > 5)
+           fprintf (ira_dump_file, "\n");
        }
     }
   return insn;

diff --git a/gcc/testsuite/gcc.target/avr/pr90706.c b/gcc/testsuite/gcc.target/avr/pr90706.c
new file mode 100644 (file)
index 0000000..4b9bcbe
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/pr90706.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+ 
+unsigned char check(float x)
+{
+   return (0.0 < x);
+}
+ /* { dg-final { scan-assembler-not "ldd" } } */
+ /* { dg-final { scan-assembler-not "std" } } */