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tcg/riscv: Improve setcond expansion
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Split out a helper function, tcg_out_setcond_int, which does not
always produce the complete boolean result, but returns a set of
flags to do so.

Based on 21af161, the same improvement for loongarch64.

Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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@rth7680
rth7680 committed May 25, 2023
1 parent 0956ecd commit f645369
Showing 1 changed file with 114 additions and 36 deletions.
150 changes: 114 additions & 36 deletions tcg/riscv/tcg-target.c.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -812,50 +812,128 @@ static void tcg_out_brcond(TCGContext *s, TCGCond cond, TCGReg arg1,
tcg_out_opc_branch(s, op, arg1, arg2, 0);
}

static void tcg_out_setcond(TCGContext *s, TCGCond cond, TCGReg ret,
TCGReg arg1, TCGReg arg2)
#define SETCOND_INV TCG_TARGET_NB_REGS
#define SETCOND_NEZ (SETCOND_INV << 1)
#define SETCOND_FLAGS (SETCOND_INV | SETCOND_NEZ)

static int tcg_out_setcond_int(TCGContext *s, TCGCond cond, TCGReg ret,
TCGReg arg1, tcg_target_long arg2, bool c2)
{
int flags = 0;

switch (cond) {
case TCG_COND_EQ:
tcg_out_opc_reg(s, OPC_SUB, ret, arg1, arg2);
tcg_out_opc_imm(s, OPC_SLTIU, ret, ret, 1);
break;
case TCG_COND_NE:
tcg_out_opc_reg(s, OPC_SUB, ret, arg1, arg2);
tcg_out_opc_reg(s, OPC_SLTU, ret, TCG_REG_ZERO, ret);
break;
case TCG_COND_LT:
tcg_out_opc_reg(s, OPC_SLT, ret, arg1, arg2);
case TCG_COND_EQ: /* -> NE */
case TCG_COND_GE: /* -> LT */
case TCG_COND_GEU: /* -> LTU */
case TCG_COND_GT: /* -> LE */
case TCG_COND_GTU: /* -> LEU */
cond = tcg_invert_cond(cond);
flags ^= SETCOND_INV;
break;
case TCG_COND_GE:
tcg_out_opc_reg(s, OPC_SLT, ret, arg1, arg2);
tcg_out_opc_imm(s, OPC_XORI, ret, ret, 1);
default:
break;
}

switch (cond) {
case TCG_COND_LE:
tcg_out_opc_reg(s, OPC_SLT, ret, arg2, arg1);
tcg_out_opc_imm(s, OPC_XORI, ret, ret, 1);
break;
case TCG_COND_GT:
tcg_out_opc_reg(s, OPC_SLT, ret, arg2, arg1);
case TCG_COND_LEU:
/*
* If we have a constant input, the most efficient way to implement
* LE is by adding 1 and using LT. Watch out for wrap around for LEU.
* We don't need to care for this for LE because the constant input
* is constrained to signed 12-bit, and 0x800 is representable in the
* temporary register.
*/
if (c2) {
if (cond == TCG_COND_LEU) {
/* unsigned <= -1 is true */
if (arg2 == -1) {
tcg_out_movi(s, TCG_TYPE_REG, ret, !(flags & SETCOND_INV));
return ret;
}
cond = TCG_COND_LTU;
} else {
cond = TCG_COND_LT;
}
tcg_debug_assert(arg2 <= 0x7ff);
if (++arg2 == 0x800) {
tcg_out_movi(s, TCG_TYPE_REG, TCG_REG_TMP0, arg2);
arg2 = TCG_REG_TMP0;
c2 = false;
}
} else {
TCGReg tmp = arg2;
arg2 = arg1;
arg1 = tmp;
cond = tcg_swap_cond(cond); /* LE -> GE */
cond = tcg_invert_cond(cond); /* GE -> LT */
flags ^= SETCOND_INV;
}
break;
case TCG_COND_LTU:
tcg_out_opc_reg(s, OPC_SLTU, ret, arg1, arg2);
default:
break;
case TCG_COND_GEU:
tcg_out_opc_reg(s, OPC_SLTU, ret, arg1, arg2);
tcg_out_opc_imm(s, OPC_XORI, ret, ret, 1);
}

switch (cond) {
case TCG_COND_NE:
flags |= SETCOND_NEZ;
if (!c2) {
tcg_out_opc_reg(s, OPC_XOR, ret, arg1, arg2);
} else if (arg2 == 0) {
ret = arg1;
} else {
tcg_out_opc_imm(s, OPC_XORI, ret, arg1, arg2);
}
break;
case TCG_COND_LEU:
tcg_out_opc_reg(s, OPC_SLTU, ret, arg2, arg1);
tcg_out_opc_imm(s, OPC_XORI, ret, ret, 1);

case TCG_COND_LT:
if (c2) {
tcg_out_opc_imm(s, OPC_SLTI, ret, arg1, arg2);
} else {
tcg_out_opc_reg(s, OPC_SLT, ret, arg1, arg2);
}
break;
case TCG_COND_GTU:
tcg_out_opc_reg(s, OPC_SLTU, ret, arg2, arg1);

case TCG_COND_LTU:
if (c2) {
tcg_out_opc_imm(s, OPC_SLTIU, ret, arg1, arg2);
} else {
tcg_out_opc_reg(s, OPC_SLTU, ret, arg1, arg2);
}
break;

default:
g_assert_not_reached();
break;
}
g_assert_not_reached();
}

return ret | flags;
}

static void tcg_out_setcond(TCGContext *s, TCGCond cond, TCGReg ret,
TCGReg arg1, tcg_target_long arg2, bool c2)
{
int tmpflags = tcg_out_setcond_int(s, cond, ret, arg1, arg2, c2);

if (tmpflags != ret) {
TCGReg tmp = tmpflags & ~SETCOND_FLAGS;

switch (tmpflags & SETCOND_FLAGS) {
case SETCOND_INV:
/* Intermediate result is boolean: simply invert. */
tcg_out_opc_imm(s, OPC_XORI, ret, tmp, 1);
break;
case SETCOND_NEZ:
/* Intermediate result is zero/non-zero: test != 0. */
tcg_out_opc_reg(s, OPC_SLTU, ret, TCG_REG_ZERO, tmp);
break;
case SETCOND_NEZ | SETCOND_INV:
/* Intermediate result is zero/non-zero: test == 0. */
tcg_out_opc_imm(s, OPC_SLTIU, ret, tmp, 1);
break;
default:
g_assert_not_reached();
}
}
}

static void tcg_out_call_int(TCGContext *s, const tcg_insn_unit *arg, bool tail)
Expand Down Expand Up @@ -1542,7 +1620,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,

case INDEX_op_setcond_i32:
case INDEX_op_setcond_i64:
tcg_out_setcond(s, args[3], a0, a1, a2);
tcg_out_setcond(s, args[3], a0, a1, a2, c2);
break;

case INDEX_op_qemu_ld_a32_i32:
Expand Down Expand Up @@ -1665,6 +1743,8 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
case INDEX_op_and_i64:
case INDEX_op_or_i64:
case INDEX_op_xor_i64:
case INDEX_op_setcond_i32:
case INDEX_op_setcond_i64:
return C_O1_I2(r, r, rI);

case INDEX_op_andc_i32:
Expand All @@ -1686,15 +1766,13 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
case INDEX_op_divu_i32:
case INDEX_op_rem_i32:
case INDEX_op_remu_i32:
case INDEX_op_setcond_i32:
case INDEX_op_mul_i64:
case INDEX_op_mulsh_i64:
case INDEX_op_muluh_i64:
case INDEX_op_div_i64:
case INDEX_op_divu_i64:
case INDEX_op_rem_i64:
case INDEX_op_remu_i64:
case INDEX_op_setcond_i64:
return C_O1_I2(r, rZ, rZ);

case INDEX_op_shl_i32:
Expand Down

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