target-ppc: implement branch-less divw[o][.]
While implementing modulo instructions figured out that the implementation uses many branches. Change the logic to achieve the branch-less code. Undefined value is set to dividend in case of invalid input. Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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@ -1097,41 +1097,39 @@ static void gen_addpcis(DisasContext *ctx)
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static inline void gen_op_arith_divw(DisasContext *ctx, TCGv ret, TCGv arg1,
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TCGv arg2, int sign, int compute_ov)
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{
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TCGLabel *l1 = gen_new_label();
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TCGLabel *l2 = gen_new_label();
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TCGv_i32 t0 = tcg_temp_local_new_i32();
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TCGv_i32 t1 = tcg_temp_local_new_i32();
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TCGv_i32 t0 = tcg_temp_new_i32();
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TCGv_i32 t1 = tcg_temp_new_i32();
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TCGv_i32 t2 = tcg_temp_new_i32();
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TCGv_i32 t3 = tcg_temp_new_i32();
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tcg_gen_trunc_tl_i32(t0, arg1);
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tcg_gen_trunc_tl_i32(t1, arg2);
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tcg_gen_brcondi_i32(TCG_COND_EQ, t1, 0, l1);
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if (sign) {
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TCGLabel *l3 = gen_new_label();
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tcg_gen_brcondi_i32(TCG_COND_NE, t1, -1, l3);
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tcg_gen_brcondi_i32(TCG_COND_EQ, t0, INT32_MIN, l1);
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gen_set_label(l3);
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tcg_gen_div_i32(t0, t0, t1);
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tcg_gen_setcondi_i32(TCG_COND_EQ, t2, t0, INT_MIN);
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tcg_gen_setcondi_i32(TCG_COND_EQ, t3, t1, -1);
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tcg_gen_and_i32(t2, t2, t3);
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tcg_gen_setcondi_i32(TCG_COND_EQ, t3, t1, 0);
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tcg_gen_or_i32(t2, t2, t3);
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tcg_gen_movi_i32(t3, 0);
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tcg_gen_movcond_i32(TCG_COND_NE, t1, t2, t3, t2, t1);
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tcg_gen_div_i32(t3, t0, t1);
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tcg_gen_extu_i32_tl(ret, t3);
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} else {
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tcg_gen_divu_i32(t0, t0, t1);
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tcg_gen_setcondi_i32(TCG_COND_EQ, t2, t1, 0);
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tcg_gen_movi_i32(t3, 0);
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tcg_gen_movcond_i32(TCG_COND_NE, t1, t2, t3, t2, t1);
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tcg_gen_divu_i32(t3, t0, t1);
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tcg_gen_extu_i32_tl(ret, t3);
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}
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if (compute_ov) {
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tcg_gen_movi_tl(cpu_ov, 0);
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tcg_gen_extu_i32_tl(cpu_ov, t2);
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tcg_gen_or_tl(cpu_so, cpu_so, cpu_ov);
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}
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tcg_gen_br(l2);
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gen_set_label(l1);
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if (sign) {
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tcg_gen_sari_i32(t0, t0, 31);
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} else {
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tcg_gen_movi_i32(t0, 0);
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}
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if (compute_ov) {
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tcg_gen_movi_tl(cpu_ov, 1);
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tcg_gen_movi_tl(cpu_so, 1);
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}
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gen_set_label(l2);
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tcg_gen_extu_i32_tl(ret, t0);
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tcg_temp_free_i32(t0);
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tcg_temp_free_i32(t1);
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tcg_temp_free_i32(t2);
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tcg_temp_free_i32(t3);
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if (unlikely(Rc(ctx->opcode) != 0))
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gen_set_Rc0(ctx, ret);
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}
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