target/mips: optimize WSBH, DSBH and DSHD

Use the same mask to avoid having to load two different constants.

Suggested-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

target/mips/translate.c

@@ -4572,12 +4572,14 @@ static void gen_bshfl (DisasContext *ctx, uint32_t op2, int rt, int rd)
     case OPC_WSBH:
         {
             TCGv t1 = tcg_temp_new();
+            TCGv t2 = tcg_const_tl(0x00FF00FF);
             tcg_gen_shri_tl(t1, t0, 8);
-            tcg_gen_andi_tl(t1, t1, 0x00FF00FF);
+            tcg_gen_and_tl(t1, t1, t2);
+            tcg_gen_and_tl(t0, t0, t2);
             tcg_gen_shli_tl(t0, t0, 8);
-            tcg_gen_andi_tl(t0, t0, ~0x00FF00FF);
             tcg_gen_or_tl(t0, t0, t1);
+            tcg_temp_free(t2);
             tcg_temp_free(t1);
             tcg_gen_ext32s_tl(cpu_gpr[rd], t0);
         }
@@ -4592,27 +4594,31 @@ static void gen_bshfl (DisasContext *ctx, uint32_t op2, int rt, int rd)
     case OPC_DSBH:
         {
             TCGv t1 = tcg_temp_new();
+            TCGv t2 = tcg_const_tl(0x00FF00FF00FF00FFULL);
             tcg_gen_shri_tl(t1, t0, 8);
-            tcg_gen_andi_tl(t1, t1, 0x00FF00FF00FF00FFULL);
+            tcg_gen_and_tl(t1, t1, t2);
+            tcg_gen_and_tl(t0, t0, t2);
             tcg_gen_shli_tl(t0, t0, 8);
-            tcg_gen_andi_tl(t0, t0, ~0x00FF00FF00FF00FFULL);
             tcg_gen_or_tl(cpu_gpr[rd], t0, t1);
+            tcg_temp_free(t2);
             tcg_temp_free(t1);
         }
         break;
     case OPC_DSHD:
         {
             TCGv t1 = tcg_temp_new();
+            TCGv t2 = tcg_const_tl(0x0000FFFF0000FFFFULL);
             tcg_gen_shri_tl(t1, t0, 16);
-            tcg_gen_andi_tl(t1, t1, 0x0000FFFF0000FFFFULL);
+            tcg_gen_and_tl(t1, t1, t2);
+            tcg_gen_and_tl(t0, t0, t2);
             tcg_gen_shli_tl(t0, t0, 16);
-            tcg_gen_andi_tl(t0, t0, ~0x0000FFFF0000FFFFULL);
             tcg_gen_or_tl(t0, t0, t1);
             tcg_gen_shri_tl(t1, t0, 32);
             tcg_gen_shli_tl(t0, t0, 32);
             tcg_gen_or_tl(cpu_gpr[rd], t0, t1);
+            tcg_temp_free(t2);
             tcg_temp_free(t1);
         }
         break;