[avr-gcc-list] Adjust REGISTER_MOVE_COST and MEMORY_MOVE_COST

[Anatoly Sokolov]

Hello.

  Now cost of moving 1, 2, 4-bytes data from register to register is 2 and
cost of moving to/from SP register is increased. But moving 1 byte of data
between registers request one MOV instruction ,moving 2 bytes two MOV
instruction or one MOVW instruction on devices which have it and etc. I have
changed REGISTER_MOVE_COST macro to consider it.

  Also cost of register to memory moves is increased by 2 that the GCC prefer
register to register moves rather register to memory moves.

  I have received ~0.6% code size decrease on test projects.

  I will be grateful for testing and feedback on this patch.


Index: gcc/config/avr/avr-protos.h
===================================================================
--- gcc/config/avr/avr-protos.h (revision 163854)
+++ gcc/config/avr/avr-protos.h (working copy)
@@ -38,6 +38,8 @@
 extern rtx avr_return_addr_rtx (int count, const_rtx tem);
 
 #ifdef TREE_CODE
+extern int avr_register_move_cost (enum machine_mode, int, int);
+extern int avr_memory_move_cost (enum machine_mode, int, bool);
 extern void asm_output_external (FILE *file, tree decl, char *name);
 extern int avr_progmem_p (tree decl, tree attributes);
 
Index: gcc/config/avr/avr.c
===================================================================
--- gcc/config/avr/avr.c        (revision 163854)
+++ gcc/config/avr/avr.c        (working copy)
@@ -5039,7 +5039,60 @@
       reg_alloc_order[i] = order[i];
 }
 
+/* Implements REGISTER_MOVE_COST.  */
 
+int
+avr_register_move_cost (enum machine_mode mode,
+                       int from, int to)
+{
+  if (from == STACK_REG)
+    return 6;
+  else if (to == STACK_REG)
+    return 12;
+  else
+    {
+      if (mode == QImode)
+       return 2;
+      if (mode == HImode)
+        {
+         if (AVR_HAVE_MOVW)
+           return 2;
+         else
+           return 4;
+       }
+      if (mode == SImode || mode ==SFmode)
+        {
+         if (AVR_HAVE_MOVW)
+           return 4;
+         else
+           return 8;
+       }
+      else
+        {
+         if (AVR_HAVE_MOVW)
+           return 8;
+         else
+           return 16;
+       }
+    }
+}
+
+/*  Implements MEMORY_MOVE_COST.  */
+
+int
+avr_memory_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
+                     int rclass ATTRIBUTE_UNUSED,
+                     bool in ATTRIBUTE_UNUSED)
+{
+  if (mode == QImode)
+    return 4;
+  if (mode == HImode)
+    return 6;
+  if (mode == SImode || mode ==SFmode)
+    return 10;
+  else
+    return 18;
+}
 /* Mutually recursive subroutine of avr_rtx_cost for calculating the
    cost of an RTX operand given its context.  X is the rtx of the
    operand, MODE is its mode, and OUTER is the rtx_code of this
Index: gcc/config/avr/avr.h
===================================================================
--- gcc/config/avr/avr.h        (revision 163854)
+++ gcc/config/avr/avr.h        (working copy)
@@ -462,15 +462,11 @@
 
 #define LEGITIMATE_CONSTANT_P(X) 1
 
-#define REGISTER_MOVE_COST(MODE, FROM, TO) ((FROM) == STACK_REG ? 6 \
-                                           : (TO) == STACK_REG ? 12 \
-                                           : 2)
+#define REGISTER_MOVE_COST(MODE, FROM, TO) \
+  avr_register_move_cost ((MODE), (FROM), (TO))
+#define MEMORY_MOVE_COST(MODE, CLASS, IN) \
+  avr_memory_move_cost ((MODE), (CLASS), (IN))
 
-#define MEMORY_MOVE_COST(MODE,CLASS,IN) ((MODE)==QImode ? 2 :  \
-                                        (MODE)==HImode ? 4 :   \
-                                        (MODE)==SImode ? 8 :   \
-                                        (MODE)==SFmode ? 8 : 16)
-
 #define BRANCH_COST(speed_p, predictable_p) 0
 
 #define SLOW_BYTE_ACCESS 0



Anatoly.