Commit 14e99210 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg: Use ctpop to generate ctz if needed 



Particularly when andc is also available, this is two insns
shorter than using clz to compute ctz.

Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent c3f8962f

tcg/tcg-op.c

+60 −40
Original line number Diff line number Diff line
@@ -497,33 +497,27 @@ void tcg_gen_ctz_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2) 
        tcg_gen_extrl_i64_i32(ret, t1);

        tcg_temp_free_i64(t1);

        tcg_temp_free_i64(t2);

    } else if (TCG_TARGET_HAS_clz_i32) {

        TCGv_i32 t1 = tcg_temp_new_i32();

        TCGv_i32 t2 = tcg_temp_new_i32();

        tcg_gen_neg_i32(t1, arg1);

        tcg_gen_xori_i32(t2, arg2, 31);

        tcg_gen_and_i32(t1, t1, arg1);

        tcg_gen_clz_i32(ret, t1, t2);

        tcg_temp_free_i32(t1);

        tcg_temp_free_i32(t2);

        tcg_gen_xori_i32(ret, ret, 31);

    } else if (TCG_TARGET_HAS_clz_i64) {

        TCGv_i32 t1 = tcg_temp_new_i32();

        TCGv_i32 t2 = tcg_temp_new_i32();

        TCGv_i64 x1 = tcg_temp_new_i64();

        TCGv_i64 x2 = tcg_temp_new_i64();

        tcg_gen_neg_i32(t1, arg1);

        tcg_gen_xori_i32(t2, arg2, 63);

        tcg_gen_and_i32(t1, t1, arg1);

        tcg_gen_extu_i32_i64(x1, t1);

        tcg_gen_extu_i32_i64(x2, t2);

        tcg_temp_free_i32(t1);

        tcg_temp_free_i32(t2);

        tcg_gen_clz_i64(x1, x1, x2);

        tcg_gen_extrl_i64_i32(ret, x1);

        tcg_temp_free_i64(x1);

        tcg_temp_free_i64(x2);

        tcg_gen_xori_i32(ret, ret, 63);

    } else if (TCG_TARGET_HAS_ctpop_i32

               || TCG_TARGET_HAS_ctpop_i64

               || TCG_TARGET_HAS_clz_i32

               || TCG_TARGET_HAS_clz_i64) {

        TCGv_i32 z, t = tcg_temp_new_i32();



        if (TCG_TARGET_HAS_ctpop_i32 || TCG_TARGET_HAS_ctpop_i64) {

            tcg_gen_subi_i32(t, arg1, 1);

            tcg_gen_andc_i32(t, t, arg1);

            tcg_gen_ctpop_i32(t, t);

        } else {

            /* Since all non-x86 hosts have clz(0) == 32, don't fight it.  */

            tcg_gen_neg_i32(t, arg1);

            tcg_gen_and_i32(t, t, arg1);

            tcg_gen_clzi_i32(t, t, 32);

            tcg_gen_xori_i32(t, t, 31);

        }

        z = tcg_const_i32(0);

        tcg_gen_movcond_i32(TCG_COND_EQ, ret, arg1, z, arg2, t);

        tcg_temp_free_i32(t);

        tcg_temp_free_i32(z);

    } else {

        gen_helper_ctz_i32(ret, arg1, arg2);

    }
@@ -531,10 +525,19 @@ void tcg_gen_ctz_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2) 


void tcg_gen_ctzi_i32(TCGv_i32 ret, TCGv_i32 arg1, uint32_t arg2)

{

    if (!TCG_TARGET_HAS_ctz_i32 && TCG_TARGET_HAS_ctpop_i32 && arg2 == 32) {

        /* This equivalence has the advantage of not requiring a fixup.  */

        TCGv_i32 t = tcg_temp_new_i32();

        tcg_gen_subi_i32(t, arg1, 1);

        tcg_gen_andc_i32(t, t, arg1);

        tcg_gen_ctpop_i32(ret, t);

        tcg_temp_free_i32(t);

    } else {

        TCGv_i32 t = tcg_const_i32(arg2);

        tcg_gen_ctz_i32(ret, arg1, t);

        tcg_temp_free_i32(t);

    }

}



void tcg_gen_clrsb_i32(TCGv_i32 ret, TCGv_i32 arg)

{
@@ -1842,16 +1845,24 @@ void tcg_gen_ctz_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2) 
{

    if (TCG_TARGET_HAS_ctz_i64) {

        tcg_gen_op3_i64(INDEX_op_ctz_i64, ret, arg1, arg2);

    } else if (TCG_TARGET_HAS_clz_i64) {

        TCGv_i64 t1 = tcg_temp_new_i64();

        TCGv_i64 t2 = tcg_temp_new_i64();

        tcg_gen_neg_i64(t1, arg1);

        tcg_gen_xori_i64(t2, arg2, 63);

        tcg_gen_and_i64(t1, t1, arg1);

        tcg_gen_clz_i64(ret, t1, t2);

        tcg_temp_free_i64(t1);

        tcg_temp_free_i64(t2);

        tcg_gen_xori_i64(ret, ret, 63);

    } else if (TCG_TARGET_HAS_ctpop_i64 || TCG_TARGET_HAS_clz_i64) {

        TCGv_i64 z, t = tcg_temp_new_i64();



        if (TCG_TARGET_HAS_ctpop_i64) {

            tcg_gen_subi_i64(t, arg1, 1);

            tcg_gen_andc_i64(t, t, arg1);

            tcg_gen_ctpop_i64(t, t);

        } else {

            /* Since all non-x86 hosts have clz(0) == 64, don't fight it.  */

            tcg_gen_neg_i64(t, arg1);

            tcg_gen_and_i64(t, t, arg1);

            tcg_gen_clzi_i64(t, t, 64);

            tcg_gen_xori_i64(t, t, 63);

        }

        z = tcg_const_i64(0);

        tcg_gen_movcond_i64(TCG_COND_EQ, ret, arg1, z, arg2, t);

        tcg_temp_free_i64(t);

        tcg_temp_free_i64(z);

    } else {

        gen_helper_ctz_i64(ret, arg1, arg2);

    }
@@ -1868,6 +1879,15 @@ void tcg_gen_ctzi_i64(TCGv_i64 ret, TCGv_i64 arg1, uint64_t arg2) 
        tcg_gen_ctz_i32(TCGV_LOW(ret), TCGV_LOW(arg1), t32);

        tcg_gen_movi_i32(TCGV_HIGH(ret), 0);

        tcg_temp_free_i32(t32);

    } else if (!TCG_TARGET_HAS_ctz_i64

               && TCG_TARGET_HAS_ctpop_i64

               && arg2 == 64) {

        /* This equivalence has the advantage of not requiring a fixup.  */

        TCGv_i64 t = tcg_temp_new_i64();

        tcg_gen_subi_i64(t, arg1, 1);

        tcg_gen_andc_i64(t, t, arg1);

        tcg_gen_ctpop_i64(ret, t);

        tcg_temp_free_i64(t);

    } else {

        TCGv_i64 t64 = tcg_const_i64(arg2);

        tcg_gen_ctz_i64(ret, arg1, t64);