[Qemu-devel] [PATCH 2/3] target-s390x: optimize (negative-) abs computation

[Aurelien Jarno <aurelien@aurel32.net>]

Now that movcond exists, it's easy to write (negative-) absolute value
using TCG code instead of an helper.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
 target-s390x/helper.h     |  2 --
 target-s390x/int_helper.c | 22 ----------------------
 target-s390x/translate.c  | 16 ++++++++++++++--
 3 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/target-s390x/helper.h b/target-s390x/helper.h
index 8d2c859..c4ec3f1 100644
--- a/target-s390x/helper.h
+++ b/target-s390x/helper.h
@@ -17,8 +17,6 @@ DEF_HELPER_4(mvst, i64, env, i64, i64, i64)
 DEF_HELPER_5(ex, i32, env, i32, i64, i64, i64)
 DEF_HELPER_FLAGS_1(abs_i32, TCG_CALL_NO_RWG_SE, i32, s32)
 DEF_HELPER_FLAGS_1(nabs_i32, TCG_CALL_NO_RWG_SE, s32, s32)
-DEF_HELPER_FLAGS_1(abs_i64, TCG_CALL_NO_RWG_SE, i64, s64)
-DEF_HELPER_FLAGS_1(nabs_i64, TCG_CALL_NO_RWG_SE, s64, s64)
 DEF_HELPER_FLAGS_4(stam, TCG_CALL_NO_WG, void, env, i32, i64, i32)
 DEF_HELPER_FLAGS_4(lam, TCG_CALL_NO_WG, void, env, i32, i64, i32)
 DEF_HELPER_4(mvcle, i32, env, i32, i64, i32)
diff --git a/target-s390x/int_helper.c b/target-s390x/int_helper.c
index cb8dd98..f53723d 100644
--- a/target-s390x/int_helper.c
+++ b/target-s390x/int_helper.c
@@ -135,28 +135,6 @@ int32_t HELPER(nabs_i32)(int32_t val)
     }
 }
 
-/* absolute value 64-bit */
-uint64_t HELPER(abs_i64)(int64_t val)
-{
-    HELPER_LOG("%s: val 0x%" PRIx64 "\n", __func__, val);
-
-    if (val < 0) {
-        return -val;
-    } else {
-        return val;
-    }
-}
-
-/* negative absolute value 64-bit */
-int64_t HELPER(nabs_i64)(int64_t val)
-{
-    if (val < 0) {
-        return val;
-    } else {
-        return -val;
-    }
-}
-
 /* count leading zeros, for find leftmost one */
 uint64_t HELPER(clz)(uint64_t v)
 {
diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index c297938..5898adb 100644
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -1304,7 +1304,13 @@ static ExitStatus help_branch(DisasContext *s, DisasCompare *c,
 
 static ExitStatus op_abs(DisasContext *s, DisasOps *o)
 {
-    gen_helper_abs_i64(o->out, o->in2);
+    TCGv_i64 z, n;
+    z = tcg_const_i64(0);
+    n = tcg_temp_new_i64();
+    tcg_gen_neg_i64(n, o->in2);
+    tcg_gen_movcond_i64(TCG_COND_LT, o->out, o->in2, z, n, o->in2);
+    tcg_temp_free_i64(n);
+    tcg_temp_free_i64(z);
     return NO_EXIT;
 }
 
@@ -2675,7 +2681,13 @@ static ExitStatus op_msdb(DisasContext *s, DisasOps *o)
 
 static ExitStatus op_nabs(DisasContext *s, DisasOps *o)
 {
-    gen_helper_nabs_i64(o->out, o->in2);
+    TCGv_i64 z, n;
+    z = tcg_const_i64(0);
+    n = tcg_temp_new_i64();
+    tcg_gen_neg_i64(n, o->in2);
+    tcg_gen_movcond_i64(TCG_COND_GE, o->out, o->in2, z, n, o->in2);
+    tcg_temp_free_i64(n);
+    tcg_temp_free_i64(z);
     return NO_EXIT;
 }
 
-- 
2.1.4