target-arm: Handle always condition codes within arm_test_cc

Handling this with TCG_COND_ALWAYS will allow these unlikely
cases to be handled without special cases in the rest of the
translator.  The TCG optimizer ought to be able to reduce
these ALWAYS conditions completely.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-id: 1441909103-24666-4-git-send-email-rth@twiddle.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 7d2e984..84a21ac 100644 (file)
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -804,6 +804,14 @@ void arm_test_cc(DisasCompare *cmp, int cc)
         tcg_gen_andc_i32(value, cpu_ZF, value);
         break;
 
+    case 14: /* always */
+    case 15: /* always */
+        /* Use the ALWAYS condition, which will fold early.
+         * It doesn't matter what we use for the value.  */
+        cond = TCG_COND_ALWAYS;
+        value = cpu_ZF;
+        goto no_invert;
+
     default:
         fprintf(stderr, "Bad condition code 0x%x\n", cc);
         abort();
@@ -813,6 +821,7 @@ void arm_test_cc(DisasCompare *cmp, int cc)
         cond = tcg_invert_cond(cond);
     }
 
+ no_invert:
     cmp->cond = cond;
     cmp->value = value;
     cmp->value_global = global;