Commit: RL78: Improve multiplication cost estimate

[Nick Clifton]

Hi DJ,

  This is the patch that I have checked in.

Cheers
  Nick

gcc/ChangeLog
2015-10-06  Nick Clifton  <ni...@redhat.com>

        * config/rl78/rl78.c (rl78_rtx_costs): Improve cost estimates for
        multiplication.

Index: gcc/config/rl78/rl78.c
===================================================================
--- gcc/config/rl78/rl78.c      (revision 228513)
+++ gcc/config/rl78/rl78.c      (working copy)
@@ -4165,12 +4165,31 @@
       return true;
     }
 
+  if (mode == HImode)
+    {
+      if (code == MULT && ! speed)
+       {
+         * total = COSTS_N_INSNS (8);
+         return true;
+       }
+      return false;
+    }
+
   if (mode == SImode)
     {
       switch (code)
        {
        case MULT:
-         if (RL78_MUL_G14)
+         if (! speed)
+           /* If we are compiling for space then we do not want to use the
+              inline SImode multiplication patterns or shift sequences.
+              The cost is not set to 1 or 5 however as we have to allow for
+              the possibility that we might be converting a leaf function
+              into a non-leaf function.  (There is no way to tell here).
+              A value of 13 seems to be a reasonable compromise for the
+              moment.  */
+           * total = COSTS_N_INSNS (13);
+         else if (RL78_MUL_G14)
            *total = COSTS_N_INSNS (14);
          else if (RL78_MUL_G13)
            *total = COSTS_N_INSNS (29);