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 7d2e9848c4717e5b36e974a078fa4ecd3023c272..84a21ace541e14c72630cfb73f7fbc316acf5ea6 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;