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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: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2016-11-22 12:40:35 +00:00
parent c3f8962f32
commit 14e99210f6
1 changed files with 60 additions and 40 deletions
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100
tcg/tcg-op.c
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@ -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);
}
@ -531,9 +525,18 @@ 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)
{
TCGv_i32 t = tcg_const_i32(arg2);
tcg_gen_ctz_i32(ret, arg1, t);
tcg_temp_free_i32(t);
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);