(record_reg_classes): Handle case of single SET between a hard

register alone in a class and a pseudo.

From-SVN: r8474

diff --git a/gcc/regclass.c b/gcc/regclass.c
index d4636d5..129fbaf 100644 (file)
--- a/gcc/regclass.c
+++ b/gcc/regclass.c
@@ -1015,6 +1015,7 @@ record_reg_classes (n_alts, n_ops, ops, modes, constraints, insn)
   int alt;
   enum op_type {OP_READ, OP_WRITE, OP_READ_WRITE} op_types[MAX_RECOG_OPERANDS];
   int i, j;
+  rtx set;
 
   /* By default, each operand is an input operand.  */
 
@@ -1349,6 +1350,31 @@ record_reg_classes (n_alts, n_ops, ops, modes, constraints, insn)
                                     (qq->cost[class] + alt_cost) * scale);
          }
     }
+
+  /* If this insn is a single set copying operand 1 to operand 0
+     and one is a pseudo with the other a hard reg that is in its
+     own register class, set the cost of that register class to -1.  */
+
+  if ((set = single_set (insn)) != 0
+      && ops[0] == SET_DEST (set) && ops[1] == SET_SRC (set)
+      && GET_CODE (ops[0]) == REG && GET_CODE (ops[1]) == REG)
+    for (i = 0; i <= 1; i++)
+      if (REGNO (ops[i]) >= FIRST_PSEUDO_REGISTER)
+       {
+         int regno = REGNO (ops[!i]);
+         enum machine_mode mode = GET_MODE (ops[!i]);
+         int class;
+
+         if (regno >= FIRST_PSEUDO_REGISTER && prefclass != 0
+             && (reg_class_size[prefclass[regno]]
+                 == CLASS_MAX_NREGS (prefclass[regno], mode)))
+           op_costs[i].cost[prefclass[regno]] = -1;
+         else if (regno < FIRST_PSEUDO_REGISTER)
+           for (class = 0; class < N_REG_CLASSES; class++)
+             if (TEST_HARD_REG_BIT (reg_class_contents[class], regno)
+                 && reg_class_size[class] == CLASS_MAX_NREGS (class, mode))
+               op_costs[i].cost[class] = -1;
+       }
 }
 \f
 /* Compute the cost of loading X into (if TO_P is non-zero) or from (if