target/riscv: optimize condition assign for scale < 0

for some cases, scale is always equal or less than 0, since lmul is not larger than 3

Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220325085902.29500-1-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/insn_trans/trans_rvv.c.inc b/target/riscv/insn_trans/trans_rvv.c.inc
index 8d675db..b336d57 100644 (file)
--- a/target/riscv/insn_trans/trans_rvv.c.inc
+++ b/target/riscv/insn_trans/trans_rvv.c.inc
@@ -1198,7 +1198,7 @@ GEN_LDST_WHOLE_TRANS(vs8r_v, 8, true)
 static inline uint32_t MAXSZ(DisasContext *s)
 {
     int scale = s->lmul - 3;
-    return scale < 0 ? s->cfg_ptr->vlen >> -scale : s->cfg_ptr->vlen << scale;
+    return s->cfg_ptr->vlen >> -scale;
 }
 
 static bool opivv_check(DisasContext *s, arg_rmrr *a)
@@ -3597,8 +3597,7 @@ static bool trans_vrgather_vx(DisasContext *s, arg_rmrr *a)
 
     if (a->vm && s->vl_eq_vlmax) {
         int scale = s->lmul - (s->sew + 3);
-        int vlmax = scale < 0 ?
-                       s->cfg_ptr->vlen >> -scale : s->cfg_ptr->vlen << scale;
+        int vlmax = s->cfg_ptr->vlen >> -scale;
         TCGv_i64 dest = tcg_temp_new_i64();
 
         if (a->rs1 == 0) {
@@ -3630,8 +3629,7 @@ static bool trans_vrgather_vi(DisasContext *s, arg_rmrr *a)
 
     if (a->vm && s->vl_eq_vlmax) {
         int scale = s->lmul - (s->sew + 3);
-        int vlmax = scale < 0 ?
-                       s->cfg_ptr->vlen >> -scale : s->cfg_ptr->vlen << scale;
+        int vlmax = s->cfg_ptr->vlen >> -scale;
         if (a->rs1 >= vlmax) {
             tcg_gen_gvec_dup_imm(MO_64, vreg_ofs(s, a->rd),
                                  MAXSZ(s), MAXSZ(s), 0);