[aarch64] Use force_reg instead of copy_to_mode_reg

[Prathamesh Kulkarni via Gcc-patches]

Hi Richard,
Based on your suggestions in the other thread, the patch uses force_reg
to avoid creating pseudo if value is already in a register.
Bootstrap+test passes on aarch64-linux-gnu.
OK to commit ?

Thanks,
Prathamesh

[aarch64] Use force_reg instead of copy_to_mode_reg.

Use force_reg instead of copy_to_mode_reg in aarch64_simd_dup_constant
and aarch64_expand_vector_init to avoid creating pseudo if original value
is already in a register.

gcc/ChangeLog:
        * config/aarch64/aarch64.cc (aarch64_simd_dup_constant): Use
        force_reg instead of copy_to_mode_reg.
        (aarch64_expand_vector_init): Likewise.

diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 0d7470c05a1..321580d7f6a 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -21968,7 +21968,7 @@ aarch64_simd_dup_constant (rtx vals)
   /* We can load this constant by using DUP and a constant in a
      single ARM register.  This will be cheaper than a vector
      load.  */
-  x = copy_to_mode_reg (inner_mode, x);
+  x = force_reg (inner_mode, x);
   return gen_vec_duplicate (mode, x);
 }
 
@@ -22082,7 +22082,7 @@ aarch64_expand_vector_init (rtx target, rtx vals)
   /* Splat a single non-constant element if we can.  */
   if (all_same)
     {
-      rtx x = copy_to_mode_reg (inner_mode, v0);
+      rtx x = force_reg (inner_mode, v0);
       aarch64_emit_move (target, gen_vec_duplicate (mode, x));
       return;
     }
@@ -22190,12 +22190,12 @@ aarch64_expand_vector_init (rtx target, rtx vals)
             vector register.  For big-endian we want that position to hold
             the last element of VALS.  */
          maxelement = BYTES_BIG_ENDIAN ? n_elts - 1 : 0;
-         rtx x = copy_to_mode_reg (inner_mode, XVECEXP (vals, 0, maxelement));
+         rtx x = force_reg (inner_mode, XVECEXP (vals, 0, maxelement));
          aarch64_emit_move (target, lowpart_subreg (mode, x, inner_mode));
        }
       else
        {
-         rtx x = copy_to_mode_reg (inner_mode, XVECEXP (vals, 0, maxelement));
+         rtx x = force_reg (inner_mode, XVECEXP (vals, 0, maxelement));
          aarch64_emit_move (target, gen_vec_duplicate (mode, x));
        }
 
@@ -22205,7 +22205,7 @@ aarch64_expand_vector_init (rtx target, rtx vals)
          rtx x = XVECEXP (vals, 0, i);
          if (matches[i][0] == maxelement)
            continue;
-         x = copy_to_mode_reg (inner_mode, x);
+         x = force_reg (inner_mode, x);
          emit_insn (GEN_FCN (icode) (target, x, GEN_INT (i)));
        }
       return;
@@ -22249,7 +22249,7 @@ aarch64_expand_vector_init (rtx target, rtx vals)
       rtx x = XVECEXP (vals, 0, i);
       if (CONST_INT_P (x) || CONST_DOUBLE_P (x))
        continue;
-      x = copy_to_mode_reg (inner_mode, x);
+      x = force_reg (inner_mode, x);
       emit_insn (GEN_FCN (icode) (target, x, GEN_INT (i)));
     }
 }