target-s390x: Use clz opcode

Signed-off-by: NRichard Henderson <rth@twiddle.net>

target/s390x/helper.h

@@ -70,7 +70,6 @@ DEF_HELPER_FLAGS_4(msdb, TCG_CALL_NO_WG, i64, env, i64, i64, i64)
 DEF_HELPER_FLAGS_3(tceb, TCG_CALL_NO_RWG_SE, i32, env, i64, i64)
 DEF_HELPER_FLAGS_3(tcdb, TCG_CALL_NO_RWG_SE, i32, env, i64, i64)
 DEF_HELPER_FLAGS_4(tcxb, TCG_CALL_NO_RWG_SE, i32, env, i64, i64, i64)
-DEF_HELPER_FLAGS_1(clz, TCG_CALL_NO_RWG_SE, i64, i64)
 DEF_HELPER_FLAGS_2(sqeb, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_2(sqdb, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_3(sqxb, TCG_CALL_NO_WG, i64, env, i64, i64)

target/s390x/int_helper.c

@@ -117,12 +117,6 @@ uint64_t HELPER(divu64)(CPUS390XState *env, uint64_t ah, uint64_t al,
     return ret;
 }
 
-/* count leading zeros, for find leftmost one */
-uint64_t HELPER(clz)(uint64_t v)
-{
-    return clz64(v);
-}
-
 uint64_t HELPER(cvd)(int32_t reg)
 {
     /* positive 0 */

target/s390x/translate.c

@@ -2249,7 +2249,7 @@ static ExitStatus op_flogr(DisasContext *s, DisasOps *o)
     gen_op_update1_cc_i64(s, CC_OP_FLOGR, o->in2);
 
     /* R1 = IN ? CLZ(IN) : 64.  */
-    gen_helper_clz(o->out, o->in2);
+    tcg_gen_clzi_i64(o->out, o->in2, 64);
 
     /* R1+1 = IN & ~(found bit).  Note that we may attempt to shift this
        value by 64, which is undefined.  But since the shift is 64 iff the