tcg/aarch64: Use tcg_constant_vec with tcg vec expanders

Improve rotrv_vec to reduce "t1 = -v2, t2 = t1 + c" to
"t1 = -v2, t2 = c - v2".  This avoids a serial dependency
between t1 and t2.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/aarch64/tcg-target.c.inc

@@ -2516,7 +2516,7 @@ void tcg_expand_vec_op(TCGOpcode opc, TCGType type, unsigned vece,
                        TCGArg a0, ...)
 {
     va_list va;
-    TCGv_vec v0, v1, v2, t1, t2;
+    TCGv_vec v0, v1, v2, t1, t2, c1;
     TCGArg a2;
 
     va_start(va, a0);
@@ -2548,8 +2548,8 @@ void tcg_expand_vec_op(TCGOpcode opc, TCGType type, unsigned vece,
 
     case INDEX_op_rotlv_vec:
         t1 = tcg_temp_new_vec(type);
-        tcg_gen_dupi_vec(vece, t1, 8 << vece);
-        tcg_gen_sub_vec(vece, t1, v2, t1);
+        c1 = tcg_constant_vec(type, vece, 8 << vece);
+        tcg_gen_sub_vec(vece, t1, v2, c1);
         /* Right shifts are negative left shifts for AArch64.  */
         vec_gen_3(INDEX_op_shlv_vec, type, vece, tcgv_vec_arg(t1),
                   tcgv_vec_arg(v1), tcgv_vec_arg(t1));
@@ -2562,9 +2562,9 @@ void tcg_expand_vec_op(TCGOpcode opc, TCGType type, unsigned vece,
     case INDEX_op_rotrv_vec:
         t1 = tcg_temp_new_vec(type);
         t2 = tcg_temp_new_vec(type);
+        c1 = tcg_constant_vec(type, vece, 8 << vece);
         tcg_gen_neg_vec(vece, t1, v2);
-        tcg_gen_dupi_vec(vece, t2, 8 << vece);
-        tcg_gen_add_vec(vece, t2, t1, t2);
+        tcg_gen_sub_vec(vece, t2, c1, v2);
         /* Right shifts are negative left shifts for AArch64.  */
         vec_gen_3(INDEX_op_shlv_vec, type, vece, tcgv_vec_arg(t1),
                   tcgv_vec_arg(v1), tcgv_vec_arg(t1));