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Commit c7e83f5f authored by yb9976's avatar yb9976
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Revised local optimizations for Mux nodes. 

The local optimization should now match the prediction of
ir_is_optimizable_mux. This fixes opt/mux.c on SPARC.
parent 0184994d
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ir/ir/iropt.c
View file @ c7e83f5f
......@@ -1736,14 +1736,12 @@ static bool is_cmp_unequal(const ir_node *node)
/**
* returns true for Cmp(x == 0) or Cmp(x != 0)
*/
static bool is_cmp_equality_zero(const ir_node *node)
static bool is_cmp_equality_zero(const ir_node *node, ir_relation relation)
{
ir_relation relation;
ir_node *right = get_Cmp_right(node);
if (!is_Const(right) || !is_Const_null(right))
return false;
relation = get_Cmp_relation(node);
return relation == ir_relation_equal
|| relation == ir_relation_less_greater
|| (!mode_is_signed(get_irn_mode(right))
......@@ -5535,30 +5533,45 @@ bool ir_is_optimizable_mux(const ir_node *sel, const ir_node *mux_false,
return true;
}
if (!is_Cmp(sel))
return false;
const ir_node *f = mux_false;
const ir_node *t = mux_true;
const ir_mode *dest_mode = get_irn_mode(f);
if (is_Cmp(sel)) {
ir_node *cmp_l = get_Cmp_left(sel);
ir_node *cmp_r = get_Cmp_right(sel);
ir_relation relation = get_Cmp_relation(sel);
if (is_Const(t)) {
/* first normalization step: try to move a constant to the false side,
* 0 preferred on false side too */
if (is_Const(t) &&
(!is_Const(f) ||
(is_Const_null(t) && !is_Const_null(f)))) {
if (!is_Const(f) || (is_Const_null(t) && !is_Const_null(f))) {
/* Mux(x, a, b) => Mux(not(x), b, a) */
t = mux_false;
f = mux_true;
relation = get_negated_relation(relation);
}
if (is_Const(f) && is_Const_null(f) && is_Const(t) && is_Const_one(t)
if (is_Const_null(f) && is_Const(t) && is_Const_one(t)
&& ir_is_optimizable_mux_set(sel, relation, dest_mode)) {
return true;
}
}
if (mode == mode_b) {
if (mode_is_int(mode) && is_cmp_equality_zero(sel, relation) && is_And(cmp_l) && f == cmp_r) {
const ir_node *and_l = get_And_left(cmp_l);
const ir_node *and_r = get_And_right(cmp_l);
if ((and_l == t || and_r == t) && is_single_bit(t)) {
/* Mux((a & (1<<n)) == 0, 0, (1<<n)) == (a & (1<<n)) xor ((1<<n)) */
/* Mux((a & (1<<n)) != 0, 0, (1<<n)) == a & (1<<n) */
return true;
}
}
}
ir_graph *irg = get_irn_irg(sel);
if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_MODEB_LOWERED) && mode == mode_b) {
/* note: after normalization, false can only happen on default */
if (is_Const(t)) {
ir_tarval *tv_t = get_Const_tarval(t);
......@@ -5574,34 +5587,15 @@ bool ir_is_optimizable_mux(const ir_node *sel, const ir_node *mux_false,
}
}
if (mode_is_int(mode) && is_cmp_equality_zero(sel)) {
const ir_node *cmp_r = get_Cmp_right(sel);
const ir_node *cmp_l = get_Cmp_left(sel);
if (is_And(cmp_l) && f == cmp_r) {
ir_node *and_l = get_And_left(cmp_l);
ir_node *and_r = get_And_right(cmp_l);
if ((and_l == t || and_r == t) && is_single_bit(t)) {
/* Mux((a & (1<<n)) == 0, 0, (1<<n)) == (a & (1<<n)) xor ((1<<n)) */
/* Mux((a & (1<<n)) != 0, 0, (1<<n)) == a & (1<<n) */
return true;
}
}
}
return false;
}
/**
* Optimize a Mux(c, 0, 1) node (sometimes called a "set" instruction)
*/
static ir_node *transform_Mux_set(ir_node *n)
static ir_node *transform_Mux_set(ir_node *n, ir_relation relation)
{
ir_node *cond = get_Mux_sel(n);
if (!is_Cmp(cond))
return n;
ir_node *left = get_Cmp_left(cond);
ir_mode *mode = get_irn_mode(left);
if (get_mode_arithmetic(mode) != irma_twos_complement)
......@@ -5612,7 +5606,7 @@ static ir_node *transform_Mux_set(ir_node *n)
return n;
ir_node *right = get_Cmp_right(cond);
ir_relation relation = get_Cmp_relation(cond) & ~ir_relation_unordered;
relation &= ~ir_relation_unordered;
/* Try to use an appropriate relation. */
if (relation == ir_relation_equal) {
......@@ -5743,29 +5737,60 @@ static ir_node *transform_node_Mux(ir_node *n)
}
}
if (is_Cmp(sel)) {
ir_node *cmp_l = get_Cmp_left(sel);
ir_node *cmp_r = get_Cmp_right(sel);
ir_relation relation = get_Cmp_relation(sel);
bool inverted = false;
if (is_Const(t)) {
/* first normalization step: try to move a constant to the false side,
* 0 preferred on false side too */
if (is_Cmp(sel) && is_Const(t) &&
(!is_Const(f) || (is_Const_null(t) && !is_Const_null(f)))) {
dbg_info *seldbgi = get_irn_dbg_info(sel);
ir_node *block = get_nodes_block(sel);
ir_relation relation = get_Cmp_relation(sel);
if (!is_Const(f) || (is_Const_null(t) && !is_Const_null(f))) {
/* Mux(x, a, b) => Mux(not(x), b, a) */
ir_node *tmp = t;
t = f;
f = tmp;
/* Mux(x, a, b) => Mux(not(x), b, a) */
relation = get_negated_relation(relation);
sel = new_rd_Cmp(seldbgi, block, get_Cmp_left(sel),
get_Cmp_right(sel), relation);
return new_rd_Mux(get_irn_dbg_info(n), get_nodes_block(n), sel, f, t, mode);
inverted = true;
}
if (is_Const(f) && is_Const_null(f) && is_Const(t) && is_Const_one(t)) {
n = transform_Mux_set(n);
if (is_Const_null(f) && is_Const(t) && is_Const_one(t)) {
n = transform_Mux_set(n, relation);
if (n != oldn)
return n;
}
}
if (mode_is_int(mode) && is_cmp_equality_zero(sel, relation) && is_And(cmp_l) && f == cmp_r) {
ir_node *and_l = get_And_left(cmp_l);
ir_node *and_r = get_And_right(cmp_l);
if ((and_l == t || and_r == t) && is_single_bit(t)) {
if (relation == ir_relation_equal) {
/* Mux((a & (1<<n)) == 0, 0, (1<<n)) == (a & (1<<n)) xor ((1<<n)) */
ir_node *block = get_nodes_block(n);
n = new_rd_Eor(get_irn_dbg_info(n), block, cmp_l, t, mode);
DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
} else {
/* Mux((a & (1<<n)) != 0, 0, (1<<n)) == a & (1<<n) */
n = cmp_l;
DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
}
return n;
}
}
/* Normalize Mux. */
if (inverted) {
dbg_info *seldbgi = get_irn_dbg_info(sel);
ir_node *block = get_nodes_block(sel);
/* Mux(x, a, b) => Mux(not(x), b, a) */
sel = new_rd_Cmp(seldbgi, block, cmp_l, cmp_r, relation);
return new_rd_Mux(get_irn_dbg_info(n), get_nodes_block(n), sel, f, t, mode);
}
}
/* the following optimizations create new mode_b nodes, so only do them
* before mode_b lowering */
......@@ -5847,31 +5872,6 @@ static ir_node *transform_node_Mux(ir_node *n)
}
}
if (is_Cmp(sel) && mode_is_int(mode) && is_cmp_equality_zero(sel)) {
ir_relation relation = get_Cmp_relation(sel);
ir_node *cmp_r = get_Cmp_right(sel);
ir_node *cmp_l = get_Cmp_left(sel);
if (is_And(cmp_l) && f == cmp_r) {
ir_node *and_l = get_And_left(cmp_l);
ir_node *and_r = get_And_right(cmp_l);
if ((and_l == t || and_r == t) && is_single_bit(t)) {
if (relation == ir_relation_equal) {
/* Mux((a & (1<<n)) == 0, 0, (1<<n)) == (a & (1<<n)) xor ((1<<n)) */
ir_node *block = get_nodes_block(n);
n = new_rd_Eor(get_irn_dbg_info(n), block, cmp_l, t, mode);
DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
} else {
/* Mux((a & (1<<n)) != 0, 0, (1<<n)) == a & (1<<n) */
n = cmp_l;
DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
}
return n;
}
}
}
return n;
}
......
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