- /**
- * @file irarch.c
- * @date 28.9.2004
- * @author Sebastian Hack
- * @brief Machine dependent firm optimizations.
- *
- * $Id$
- */
+/*
+ * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @brief Machine dependent Firm optimizations.
+ * @date 28.9.2004
+ * @author Sebastian Hack, Michael Beck
+ * @version $Id$
+ *
+ * Implements "Strength Reduction of Multiplications by Integer Constants"
+ * by Youfeng Wu.
+ * Implements Division and Modulo by Consts from "Hackers Delight",
+ */
+#include "config.h"
#include <stdlib.h>
#include <assert.h>
#include "iropt_t.h"
#include "ircons_t.h"
#include "irgmod.h"
-#include "irvrfy.h"
-#include "tv.h"
+#include "irverify.h"
+#include "tv_t.h"
#include "dbginfo_t.h"
#include "iropt_dbg.h"
#include "irflag_t.h"
-#include "firmstat.h"
+#include "irhooks.h"
#include "ircons.h"
#include "irarch.h"
+#include "irflag.h"
+#include "be.h"
+#include "error.h"
+
+/** The bit mask, which optimizations to apply. */
+static arch_dep_opts_t opts;
+void arch_dep_set_opts(arch_dep_opts_t the_opts)
+{
+ opts = the_opts;
+}
-#undef DEB
+/** check, whether a mode allows a Mulh instruction. */
+static int allow_Mulh(const ir_settings_arch_dep_t *params, ir_mode *mode)
+{
+ if (get_mode_size_bits(mode) > params->max_bits_for_mulh)
+ return 0;
+ return (mode_is_signed(mode) && params->allow_mulhs) || (!mode_is_signed(mode) && params->allow_mulhu);
+}
-#define MAX_BITSTR 64
+/**
+ * An instruction,
+ */
+typedef struct instruction instruction;
+struct instruction {
+ insn_kind kind; /**< the instruction kind */
+ instruction *in[2]; /**< the ins */
+ unsigned shift_count; /**< shift count for LEA and SHIFT */
+ ir_node *irn; /**< the generated node for this instruction if any. */
+ int costs; /**< the costs for this instruction */
+};
-/** The params got from the factopry in arch_dep_init(...). */
-static const arch_dep_params_t *params = NULL;
+/**
+ * The environment for the strength reduction of multiplications.
+ */
+typedef struct mul_env {
+ struct obstack obst; /**< an obstack for local space. */
+ const ir_settings_arch_dep_t *params;
+ ir_mode *mode; /**< the mode of the multiplication constant */
+ unsigned bits; /**< number of bits in the mode */
+ unsigned max_S; /**< the maximum LEA shift value. */
+ instruction *root; /**< the root of the instruction tree */
+ ir_node *op; /**< the operand that is multiplied */
+ ir_node *blk; /**< the block where the new graph is built */
+ ir_graph *irg;
+ dbg_info *dbg; /**< the debug info for the new graph. */
+ ir_mode *shf_mode; /**< the (unsigned) mode for the shift constants */
+ int fail; /**< set to 1 if the instruction sequence fails the constraints */
+ int n_shift; /**< maximum number of allowed shift instructions */
-/** The bit mask, which optimizations to apply. */
-static arch_dep_opts_t opts;
+ evaluate_costs_func evaluate; /**< the evaluate callback */
+} mul_env;
-void arch_dep_init(arch_dep_params_factory_t factory)
+/**
+ * Some kind of default evaluator. Return the cost of
+ * instructions.
+ */
+static int default_evaluate(insn_kind kind, const ir_mode *mode, ir_tarval *tv)
{
- opts = arch_dep_none;
+ (void) mode;
+ (void) tv;
- if(factory != NULL)
- params = factory();
+ if (kind == MUL)
+ return 13;
+ return 1;
}
-void arch_dep_set_opts(arch_dep_opts_t the_opts) {
- opts = the_opts;
+/**
+ * emit a LEA (or an Add) instruction
+ */
+static instruction *emit_LEA(mul_env *env, instruction *a, instruction *b, unsigned shift)
+{
+ instruction *res = OALLOC(&env->obst, instruction);
+ res->kind = shift > 0 ? LEA : ADD;
+ res->in[0] = a;
+ res->in[1] = b;
+ res->shift_count = shift;
+ res->irn = NULL;
+ res->costs = -1;
+ return res;
}
-ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn)
+/**
+ * emit a SHIFT (or an Add or a Zero) instruction
+ */
+static instruction *emit_SHIFT(mul_env *env, instruction *a, unsigned shift)
{
- ir_node *block = get_nodes_block(irn);
- ir_node *res = irn;
- ir_node *operand = NULL;
- ir_node *left, *right;
- ir_mode *mode = get_irn_mode(irn);
- tarval *tv = NULL;
+ instruction *res = OALLOC(&env->obst, instruction);
+ if (shift == env->bits) {
+ /* a 2^bits with bits resolution is a zero */
+ res->kind = ZERO;
+ res->in[0] = NULL;
+ res->in[1] = NULL;
+ res->shift_count = 0;
+ } else if (shift != 1) {
+ res->kind = SHIFT;
+ res->in[0] = a;
+ res->in[1] = NULL;
+ res->shift_count = shift;
+ } else {
+ res->kind = ADD;
+ res->in[0] = a;
+ res->in[1] = a;
+ res->shift_count = 0;
+ }
+ res->irn = NULL;
+ res->costs = -1;
+ return res;
+}
- /* If the architecture dependent optimizations were not initialized
- or this optimization was not enabled. */
- if(params == NULL || (opts & arch_dep_mul_to_shift) == 0)
- return irn;
+/**
+ * emit a SUB instruction
+ */
+static instruction *emit_SUB(mul_env *env, instruction *a, instruction *b)
+{
+ instruction *res = OALLOC(&env->obst, instruction);
+ res->kind = SUB;
+ res->in[0] = a;
+ res->in[1] = b;
+ res->shift_count = 0;
+ res->irn = NULL;
+ res->costs = -1;
+ return res;
+}
- if(is_ir_node(irn)
- && get_irn_opcode(irn) == iro_Mul
- && mode_is_int(mode)) {
+/**
+ * emit the ROOT instruction
+ */
+static instruction *emit_ROOT(mul_env *env, ir_node *root_op)
+{
+ instruction *res = OALLOC(&env->obst, instruction);
+ res->kind = ROOT;
+ res->in[0] = NULL;
+ res->in[1] = NULL;
+ res->shift_count = 0;
+ res->irn = root_op;
+ res->costs = 0;
+ return res;
+}
- left = get_binop_left(irn);
- right = get_binop_right(irn);
- /* Look, if one operand is a constant. */
- if(get_irn_opcode(left) == iro_Const) {
- tv = get_Const_tarval(left);
- operand = right;
- } else if(get_irn_opcode(right) == iro_Const) {
- tv = get_Const_tarval(right);
- operand = left;
+/**
+ * Returns the condensed representation of the tarval tv
+ */
+static unsigned char *value_to_condensed(mul_env *env, ir_tarval *tv, int *pr)
+{
+ ir_mode *mode = get_tarval_mode(tv);
+ int bits = get_mode_size_bits(mode);
+ char *bitstr = get_tarval_bitpattern(tv);
+ int i, l, r;
+ unsigned char *R = (unsigned char*)obstack_alloc(&env->obst, bits);
+
+ l = r = 0;
+ for (i = 0; bitstr[i] != '\0'; ++i) {
+ if (bitstr[i] == '1') {
+ R[r] = i - l;
+ l = i;
+ ++r;
}
+ }
+ free(bitstr);
- if(tv != NULL) {
- int maximum_shifts = params->maximum_shifts;
- int also_use_subs = params->also_use_subs;
- int highest_shift_amount = params->highest_shift_amount;
-
- char *bitstr = get_tarval_bitpattern(tv);
- char *p;
- int i, last = 0;
- int counter = 0;
- int curr_bit;
- int compr_len = 0;
- char compr[MAX_BITSTR];
-
- int singleton;
- int end_of_group;
- int shift_with_sub[MAX_BITSTR] = { 0 };
- int shift_without_sub[MAX_BITSTR] = { 0 };
- int shift_with_sub_pos = 0;
- int shift_without_sub_pos = 0;
-
-#if DEB
- {
- int val = (int) get_tarval_long(tv);
- fprintf(stderr, "Found mul with %d(%x) = ", val, val);
- for(p = bitstr; *p != '\0'; p++)
- printf("%c", *p);
- printf("\n");
+ *pr = r;
+ return R;
+}
+
+/**
+ * Calculate the gain when using the generalized complementary technique
+ */
+static int calculate_gain(unsigned char *R, int r)
+{
+ int max_gain = 0;
+ int idx = -1, i;
+ int gain;
+
+ /* the gain for r == 1 */
+ gain = 2 - 3 - R[0];
+ for (i = 2; i < r; ++i) {
+ /* calculate the gain for r from the gain for r-1 */
+ gain += 2 - R[i - 1];
+
+ if (gain > max_gain) {
+ max_gain = gain;
+ idx = i;
+ }
+ }
+ return idx;
+}
+
+/**
+ * Calculates the condensed complement of a given (R,r) tuple
+ */
+static unsigned char *complement_condensed(mul_env *env, unsigned char *R, int r, int gain, int *prs)
+{
+ unsigned char *value = (unsigned char*)obstack_alloc(&env->obst, env->bits);
+ int i, l, j;
+ unsigned char c;
+
+ memset(value, 0, env->bits);
+
+ j = 0;
+ for (i = 0; i < gain; ++i) {
+ j += R[i];
+ value[j] = 1;
+ }
+
+ /* negate and propagate 1 */
+ c = 1;
+ for (i = 0; i <= j; ++i) {
+ unsigned char v = !value[i];
+
+ value[i] = v ^ c;
+ c = v & c;
+ }
+
+ /* condense it again */
+ l = r = 0;
+ R = value;
+ for (i = 0; i <= j; ++i) {
+ if (value[i] == 1) {
+ R[r] = i - l;
+ l = i;
+ ++r;
+ }
+ }
+
+ *prs = r;
+ return R;
+}
+
+/**
+ * creates a tarval from a condensed representation.
+ */
+static ir_tarval *condensed_to_value(mul_env *env, unsigned char *R, int r)
+{
+ ir_tarval *res, *tv;
+ int i, j;
+
+ j = 0;
+ tv = get_mode_one(env->mode);
+ res = NULL;
+ for (i = 0; i < r; ++i) {
+ j = R[i];
+ if (j) {
+ ir_tarval *t = new_tarval_from_long(j, mode_Iu);
+ tv = tarval_shl(tv, t);
+ }
+ res = res ? tarval_add(res, tv) : tv;
+ }
+ return res;
+}
+
+/* forward */
+static instruction *basic_decompose_mul(mul_env *env, unsigned char *R, int r, ir_tarval *N);
+
+/*
+ * handle simple cases with up-to 2 bits set
+ */
+static instruction *decompose_simple_cases(mul_env *env, unsigned char *R, int r, ir_tarval *N)
+{
+ instruction *ins, *ins2;
+
+ (void) N;
+ if (r == 1) {
+ return emit_SHIFT(env, env->root, R[0]);
+ } else {
+ assert(r == 2);
+
+ ins = env->root;
+ if (R[1] <= env->max_S) {
+ ins = emit_LEA(env, ins, ins, R[1]);
+ if (R[0] != 0) {
+ ins = emit_SHIFT(env, ins, R[0]);
}
-#endif
-
- for(p = bitstr; *p != '\0'; p++) {
- int bit = *p != '0';
-
- switch(bit - last) {
- case -1: // The last was 1 we are now at 0
- case 1: // The last was 0 and we are now at 1
- compr[compr_len++] = counter;
- counter = 1;
- break;
- default:
- counter++;
- }
+ return ins;
+ }
+ if (R[0] != 0) {
+ ins = emit_SHIFT(env, ins, R[0]);
+ }
+
+ ins2 = emit_SHIFT(env, env->root, R[0] + R[1]);
+ return emit_LEA(env, ins, ins2, 0);
+ }
+}
- last = bit;
+/**
+ * Main decompose driver.
+ */
+static instruction *decompose_mul(mul_env *env, unsigned char *R, int r, ir_tarval *N)
+{
+ unsigned i;
+ int gain;
+
+ if (r <= 2)
+ return decompose_simple_cases(env, R, r, N);
+
+ if (env->params->also_use_subs) {
+ gain = calculate_gain(R, r);
+ if (gain > 0) {
+ instruction *instr1, *instr2;
+ unsigned char *R1, *R2;
+ int r1, r2, i, k, j;
+
+ R1 = complement_condensed(env, R, r, gain, &r1);
+ r2 = r - gain + 1;
+ R2 = (unsigned char*)obstack_alloc(&env->obst, r2);
+
+ k = 1;
+ for (i = 0; i < gain; ++i) {
+ k += R[i];
+ }
+ R2[0] = k;
+ R2[1] = R[gain] - 1;
+ j = 2;
+ if (R2[1] == 0) {
+ /* Two identical bits: normalize */
+ ++R2[0];
+ --j;
+ --r2;
+ }
+ for (i = gain + 1; i < r; ++i) {
+ R2[j++] = R[i];
}
- compr[compr_len++] = counter;
+ instr1 = decompose_mul(env, R1, r1, NULL);
+ instr2 = decompose_mul(env, R2, r2, NULL);
+ return emit_SUB(env, instr2, instr1);
+ }
+ }
+
+ if (N == NULL)
+ N = condensed_to_value(env, R, r);
+
+ for (i = env->max_S; i > 0; --i) {
+ ir_tarval *div_res, *mod_res;
+ ir_tarval *tv = new_tarval_from_long((1 << i) + 1, env->mode);
-#ifdef DEF
- {
- const char *prefix = "";
- for(i = 0; i < compr_len; i++, prefix = ",")
- fprintf(stderr, "%s%d", prefix, compr[i]);
- fprintf("\n");
+ div_res = tarval_divmod(N, tv, &mod_res);
+ if (mod_res == get_mode_null(env->mode)) {
+ unsigned char *Rs;
+ int rs;
+
+ Rs = value_to_condensed(env, div_res, &rs);
+ if (rs < r) {
+ instruction *N1 = decompose_mul(env, Rs, rs, div_res);
+ return emit_LEA(env, N1, N1, i);
}
-#endif
+ }
+ }
+ return basic_decompose_mul(env, R, r, N);
+}
- // Go over all recorded one groups.
- curr_bit = compr[0];
+#define IMAX(a,b) ((a) > (b) ? (a) : (b))
- for(i = 1; i < compr_len; i = end_of_group + 2) {
- int j, zeros_in_group, ones_in_group;
+/**
+ * basic decomposition routine
+ */
+static instruction *basic_decompose_mul(mul_env *env, unsigned char *R, int r, ir_tarval *N)
+{
+ instruction *Ns;
+ unsigned t;
- ones_in_group = compr[i];
- zeros_in_group = 0;
+ if (R[0] == 0) { /* Case 1 */
+ t = R[1] > IMAX(env->max_S, R[1]);
+ R[1] -= t;
+ Ns = decompose_mul(env, &R[1], r - 1, N);
+ return emit_LEA(env, env->root, Ns, t);
+ } else if (R[0] <= env->max_S) { /* Case 2 */
+ t = R[0];
+ R[1] += t;
+ Ns = decompose_mul(env, &R[1], r - 1, N);
+ return emit_LEA(env, Ns, env->root, t);
+ } else {
+ t = R[0];
+ R[0] = 0;
+ Ns = decompose_mul(env, R, r, N);
+ return emit_SHIFT(env, Ns, t);
+ }
+}
- // Scan for singular 0s in a sequence
- for(j = i + 1; j < compr_len && compr[j] == 1; j += 2) {
- zeros_in_group += 1;
- ones_in_group += (j + 1 < compr_len ? compr[j + 1] : 0);
- }
- end_of_group = j - 1;
+/**
+ * recursive build the graph form the instructions.
+ *
+ * @param env the environment
+ * @param inst the instruction
+ */
+static ir_node *build_graph(mul_env *env, instruction *inst)
+{
+ ir_node *l, *r, *c;
+ ir_graph *irg = env->irg;
+
+ if (inst->irn)
+ return inst->irn;
+
+ switch (inst->kind) {
+ case LEA:
+ l = build_graph(env, inst->in[0]);
+ r = build_graph(env, inst->in[1]);
+ c = new_r_Const_long(irg, env->shf_mode, inst->shift_count);
+ r = new_rd_Shl(env->dbg, env->blk, r, c, env->mode);
+ return inst->irn = new_rd_Add(env->dbg, env->blk, l, r, env->mode);
+ case SHIFT:
+ l = build_graph(env, inst->in[0]);
+ c = new_r_Const_long(irg, env->shf_mode, inst->shift_count);
+ return inst->irn = new_rd_Shl(env->dbg, env->blk, l, c, env->mode);
+ case SUB:
+ l = build_graph(env, inst->in[0]);
+ r = build_graph(env, inst->in[1]);
+ return inst->irn = new_rd_Sub(env->dbg, env->blk, l, r, env->mode);
+ case ADD:
+ l = build_graph(env, inst->in[0]);
+ r = build_graph(env, inst->in[1]);
+ return inst->irn = new_rd_Add(env->dbg, env->blk, l, r, env->mode);
+ case ZERO:
+ return inst->irn = new_r_Const(irg, get_mode_null(env->mode));
+ default:
+ panic("Unsupported instruction kind");
+ }
+}
- if(zeros_in_group >= ones_in_group - 1)
- end_of_group = i;
+/**
+ * Calculate the costs for the given instruction sequence.
+ * Note that additional costs due to higher register pressure are NOT evaluated yet
+ */
+static int evaluate_insn(mul_env *env, instruction *inst)
+{
+ int costs;
-#ifdef DEB
- fprintf(stderr, " i:%d, eg:%d\n", i, end_of_group);
-#endif
+ if (inst->costs >= 0) {
+ /* was already evaluated */
+ return 0;
+ }
- singleton = compr[i] == 1 && i == end_of_group;
- for(j = i; j <= end_of_group; j += 2) {
- int curr_ones = compr[j];
- int biased_curr_bit = curr_bit + 1;
- int k;
+ switch (inst->kind) {
+ case LEA:
+ case SUB:
+ case ADD:
+ costs = evaluate_insn(env, inst->in[0]);
+ costs += evaluate_insn(env, inst->in[1]);
+ costs += env->evaluate(inst->kind, env->mode, NULL);
+ inst->costs = costs;
+ return costs;
+ case SHIFT:
+ if (inst->shift_count > env->params->highest_shift_amount)
+ env->fail = 1;
+ if (env->n_shift <= 0)
+ env->fail = 1;
+ else
+ --env->n_shift;
+ costs = evaluate_insn(env, inst->in[0]);
+ costs += env->evaluate(inst->kind, env->mode, NULL);
+ inst->costs = costs;
+ return costs;
+ case ZERO:
+ inst->costs = costs = env->evaluate(inst->kind, env->mode, NULL);
+ return costs;
+ case MUL:
+ case ROOT:
+ break;
+ }
+ panic("Unsupported instruction kind");
+}
-#ifdef DEB
- fprintf(stderr, " j:%d, ones:%d\n", j, curr_ones);
-#endif
+/**
+ * Evaluate the replacement instructions and build a new graph
+ * if faster than the Mul.
+ * Returns the root of the new graph then or irn otherwise.
+ *
+ * @param irn the Mul operation
+ * @param operand the multiplication operand
+ * @param tv the multiplication constant
+ *
+ * @return the new graph
+ */
+static ir_node *do_decomposition(ir_node *irn, ir_node *operand, ir_tarval *tv)
+{
+ mul_env env;
+ instruction *inst;
+ unsigned char *R;
+ int r;
+ ir_node *res = irn;
+ int mul_costs;
- // If this ones group is a singleton group (it has no
- // singleton zeros inside
- if(singleton)
- shift_with_sub[shift_with_sub_pos++] = biased_curr_bit;
- else if(j == i)
- shift_with_sub[shift_with_sub_pos++] = -biased_curr_bit;
+ obstack_init(&env.obst);
+ env.params = be_get_backend_param()->dep_param;
+ env.mode = get_tarval_mode(tv);
+ env.bits = (unsigned)get_mode_size_bits(env.mode);
+ env.max_S = 3;
+ env.root = emit_ROOT(&env, operand);
+ env.fail = 0;
+ env.n_shift = env.params->maximum_shifts;
+ env.evaluate = env.params->evaluate != NULL ? env.params->evaluate : default_evaluate;
+ env.irg = get_irn_irg(irn);
- for(k = 0; k < curr_ones; k++)
- shift_without_sub[shift_without_sub_pos++] = biased_curr_bit + k;
+ R = value_to_condensed(&env, tv, &r);
+ inst = decompose_mul(&env, R, r, tv);
- curr_bit += curr_ones;
- biased_curr_bit = curr_bit + 1;
+ /* the paper suggests 70% here */
+ mul_costs = (env.evaluate(MUL, env.mode, tv) * 7 + 5) / 10;
+ if (evaluate_insn(&env, inst) <= mul_costs && !env.fail) {
+ env.op = operand;
+ env.blk = get_nodes_block(irn);
+ env.dbg = get_irn_dbg_info(irn);
+ env.shf_mode = find_unsigned_mode(env.mode);
+ if (env.shf_mode == NULL)
+ env.shf_mode = mode_Iu;
- if(!singleton && j == end_of_group)
- shift_with_sub[shift_with_sub_pos++] = biased_curr_bit;
- else if(j != end_of_group)
- shift_with_sub[shift_with_sub_pos++] = -biased_curr_bit;
+ res = build_graph(&env, inst);
+ }
+ obstack_free(&env.obst, NULL);
+ return res;
+}
- curr_bit += compr[j + 1];
- }
+/* Replace Muls with Shifts and Add/Subs. */
+ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn)
+{
+ ir_node *res = irn;
+ ir_mode *mode = get_irn_mode(irn);
+ ir_graph *irg;
+ ir_node *left;
+ ir_node *right;
+ ir_node *operand;
+ ir_tarval *tv;
+ const ir_settings_arch_dep_t *params = be_get_backend_param()->dep_param;
- }
- {
- int *shifts = shift_with_sub;
- int n = shift_with_sub_pos;
- int highest_shift_wide = 0;
- int highest_shift_seq = 0;
- int last_shift = 0;
-
- /* If we may not use subs, or we can achive the same with adds,
- prefer adds. */
- if(!also_use_subs || shift_with_sub_pos >= shift_without_sub_pos) {
- shifts = shift_without_sub;
- n = shift_without_sub_pos;
- }
+ /* If the architecture dependent optimizations were not initialized
+ or this optimization was not enabled. */
+ if (params == NULL || (opts & arch_dep_mul_to_shift) == 0)
+ return irn;
- /* If the number of needed shifts exceeds the given maximum,
- use the Mul and exit. */
- if(n > maximum_shifts) {
-#ifdef DEB
- fprintf(stderr, "Only allowed %d shifts, but %d are needed\n",
- maximum_shifts, n);
-#endif
- return irn;
- }
+ if (!is_Mul(irn) || !mode_is_int(mode))
+ return res;
- /* Compute the highest shift needed for both, the
- sequential and wide representations. */
- for(i = 0; i < n; i++) {
- int curr = abs(shifts[i]);
- int curr_seq = curr - last;
+ /* we should never do the reverse transformations again
+ (like x+x -> 2*x) */
+ irg = get_irn_irg(irn);
+ set_irg_state(irg, IR_GRAPH_STATE_ARCH_DEP);
- highest_shift_wide = curr > highest_shift_wide ? curr
- : highest_shift_wide;
- highest_shift_seq = curr_seq > highest_shift_seq ? curr_seq
- : highest_shift_seq;
+ left = get_binop_left(irn);
+ right = get_binop_right(irn);
+ tv = NULL;
+ operand = NULL;
- last_shift = curr;
- }
+ /* Look, if one operand is a constant. */
+ if (is_Const(left)) {
+ tv = get_Const_tarval(left);
+ operand = right;
+ } else if (is_Const(right)) {
+ tv = get_Const_tarval(right);
+ operand = left;
+ }
+
+ if (tv != NULL) {
+ res = do_decomposition(irn, operand, tv);
+
+ if (res != irn) {
+ hook_arch_dep_replace_mul_with_shifts(irn);
+ exchange(irn, res);
+ }
+ }
+
+ return res;
+}
+
+/**
+ * calculated the ld2 of a tarval if tarval is 2^n, else returns -1.
+ */
+static int tv_ld2(ir_tarval *tv, int bits)
+{
+ int i, k = 0, num;
+
+ for (num = i = 0; i < bits; ++i) {
+ unsigned char v = get_tarval_sub_bits(tv, i);
- /* If the highest shift amount is greater than the given limit,
- give back the Mul */
- if(highest_shift_seq > highest_shift_amount) {
-#ifdef DEB
- fprintf(stderr, "Shift argument %d exceeds maximum %d\n",
- highest_shift_seq, highest_shift_amount);
-#endif
- return irn;
+ if (v) {
+ int j;
+
+ for (j = 0; j < 8; ++j)
+ if ((1 << j) & v) {
+ ++num;
+ k = 8 * i + j;
}
+ }
+ }
+ if (num == 1)
+ return k;
+ return -1;
+}
+
+
+/* for shorter lines */
+#define ABS(a) tarval_abs(a)
+#define NEG(a) tarval_neg(a)
+#define NOT(a) tarval_not(a)
+#define SHL(a, b) tarval_shl(a, b)
+#define SHR(a, b) tarval_shr(a, b)
+#define ADD(a, b) tarval_add(a, b)
+#define SUB(a, b) tarval_sub(a, b, NULL)
+#define MUL(a, b) tarval_mul(a, b)
+#define DIV(a, b) tarval_div(a, b)
+#define MOD(a, b) tarval_mod(a, b)
+#define CMP(a, b) tarval_cmp(a, b)
+#define CNV(a, m) tarval_convert_to(a, m)
+#define ONE(m) get_mode_one(m)
+#define ZERO(m) get_mode_null(m)
+
+/** The result of a the magic() function. */
+struct ms {
+ ir_tarval *M; /**< magic number */
+ int s; /**< shift amount */
+ int need_add; /**< an additional add is needed */
+ int need_sub; /**< an additional sub is needed */
+};
+
+/**
+ * Signed division by constant d: calculate the Magic multiplier M and the shift amount s
+ *
+ * see Hacker's Delight: 10-6 Integer Division by Constants: Incorporation into a Compiler
+ */
+static struct ms magic(ir_tarval *d)
+{
+ ir_mode *mode = get_tarval_mode(d);
+ ir_mode *u_mode = find_unsigned_mode(mode);
+ int bits = get_mode_size_bits(u_mode);
+ int p;
+ ir_tarval *ad, *anc, *delta, *q1, *r1, *q2, *r2, *t; /* unsigned */
+ ir_relation d_cmp, M_cmp;
+
+ ir_tarval *bits_minus_1, *two_bits_1;
+
+ struct ms mag;
+
+ tarval_int_overflow_mode_t rem = tarval_get_integer_overflow_mode();
+
+ /* we need overflow mode to work correctly */
+ tarval_set_integer_overflow_mode(TV_OVERFLOW_WRAP);
+
+ /* 2^(bits-1) */
+ bits_minus_1 = new_tarval_from_long(bits - 1, u_mode);
+ two_bits_1 = SHL(get_mode_one(u_mode), bits_minus_1);
+
+ ad = CNV(ABS(d), u_mode);
+ t = ADD(two_bits_1, SHR(CNV(d, u_mode), bits_minus_1));
+ anc = SUB(SUB(t, ONE(u_mode)), MOD(t, ad)); /* Absolute value of nc */
+ p = bits - 1; /* Init: p */
+ q1 = DIV(two_bits_1, anc); /* Init: q1 = 2^p/|nc| */
+ r1 = SUB(two_bits_1, MUL(q1, anc)); /* Init: r1 = rem(2^p, |nc|) */
+ q2 = DIV(two_bits_1, ad); /* Init: q2 = 2^p/|d| */
+ r2 = SUB(two_bits_1, MUL(q2, ad)); /* Init: r2 = rem(2^p, |d|) */
+
+ do {
+ ++p;
+ q1 = ADD(q1, q1); /* Update q1 = 2^p/|nc| */
+ r1 = ADD(r1, r1); /* Update r1 = rem(2^p, |nc|) */
+
+ if (CMP(r1, anc) & ir_relation_greater_equal) {
+ q1 = ADD(q1, ONE(u_mode));
+ r1 = SUB(r1, anc);
+ }
+
+ q2 = ADD(q2, q2); /* Update q2 = 2^p/|d| */
+ r2 = ADD(r2, r2); /* Update r2 = rem(2^p, |d|) */
+
+ if (CMP(r2, ad) & ir_relation_greater_equal) {
+ q2 = ADD(q2, ONE(u_mode));
+ r2 = SUB(r2, ad);
+ }
+
+ delta = SUB(ad, r2);
+ } while (CMP(q1, delta) & ir_relation_less || (CMP(q1, delta) & ir_relation_equal && CMP(r1, ZERO(u_mode)) & ir_relation_equal));
+
+ d_cmp = CMP(d, ZERO(mode));
+
+ if (d_cmp & ir_relation_greater_equal)
+ mag.M = ADD(CNV(q2, mode), ONE(mode));
+ else
+ mag.M = SUB(ZERO(mode), ADD(CNV(q2, mode), ONE(mode)));
+
+ M_cmp = CMP(mag.M, ZERO(mode));
+
+ mag.s = p - bits;
+
+ /* need an add if d > 0 && M < 0 */
+ mag.need_add = d_cmp & ir_relation_greater && M_cmp & ir_relation_less;
+
+ /* need a sub if d < 0 && M > 0 */
+ mag.need_sub = d_cmp & ir_relation_less && M_cmp & ir_relation_greater;
+
+ tarval_set_integer_overflow_mode(rem);
+
+ return mag;
+}
+
+/** The result of the magicu() function. */
+struct mu {
+ ir_tarval *M; /**< magic add constant */
+ int s; /**< shift amount */
+ int need_add; /**< add indicator */
+};
+
+/**
+ * Unsigned division by constant d: calculate the Magic multiplier M and the shift amount s
+ *
+ * see Hacker's Delight: 10-10 Integer Division by Constants: Incorporation into a Compiler (Unsigned)
+ */
+static struct mu magicu(ir_tarval *d)
+{
+ ir_mode *mode = get_tarval_mode(d);
+ int bits = get_mode_size_bits(mode);
+ int p;
+ ir_tarval *nc, *delta, *q1, *r1, *q2, *r2;
+ ir_tarval *bits_minus_1, *two_bits_1, *seven_ff;
+
+ struct mu magu;
+
+ tarval_int_overflow_mode_t rem = tarval_get_integer_overflow_mode();
+
+ /* we need overflow mode to work correctly */
+ tarval_set_integer_overflow_mode(TV_OVERFLOW_WRAP);
+
+ bits_minus_1 = new_tarval_from_long(bits - 1, mode);
+ two_bits_1 = SHL(get_mode_one(mode), bits_minus_1);
+ seven_ff = SUB(two_bits_1, ONE(mode));
+
+ magu.need_add = 0; /* initialize the add indicator */
+ nc = SUB(NEG(ONE(mode)), MOD(NEG(d), d));
+ p = bits - 1; /* Init: p */
+ q1 = DIV(two_bits_1, nc); /* Init: q1 = 2^p/nc */
+ r1 = SUB(two_bits_1, MUL(q1, nc)); /* Init: r1 = rem(2^p, nc) */
+ q2 = DIV(seven_ff, d); /* Init: q2 = (2^p - 1)/d */
+ r2 = SUB(seven_ff, MUL(q2, d)); /* Init: r2 = rem(2^p - 1, d) */
+
+ do {
+ ++p;
+ if (CMP(r1, SUB(nc, r1)) & ir_relation_greater_equal) {
+ q1 = ADD(ADD(q1, q1), ONE(mode));
+ r1 = SUB(ADD(r1, r1), nc);
+ }
+ else {
+ q1 = ADD(q1, q1);
+ r1 = ADD(r1, r1);
+ }
+
+ if (CMP(ADD(r2, ONE(mode)), SUB(d, r2)) & ir_relation_greater_equal) {
+ if (CMP(q2, seven_ff) & ir_relation_greater_equal)
+ magu.need_add = 1;
+
+ q2 = ADD(ADD(q2, q2), ONE(mode));
+ r2 = SUB(ADD(ADD(r2, r2), ONE(mode)), d);
+ }
+ else {
+ if (CMP(q2, two_bits_1) & ir_relation_greater_equal)
+ magu.need_add = 1;
+
+ q2 = ADD(q2, q2);
+ r2 = ADD(ADD(r2, r2), ONE(mode));
+ }
+ delta = SUB(SUB(d, ONE(mode)), r2);
+ } while (p < 2*bits &&
+ (CMP(q1, delta) & ir_relation_less || (CMP(q1, delta) & ir_relation_equal && CMP(r1, ZERO(mode)) & ir_relation_equal)));
+
+ magu.M = ADD(q2, ONE(mode)); /* Magic number */
+ magu.s = p - bits; /* and shift amount */
+
+ tarval_set_integer_overflow_mode(rem);
+
+ return magu;
+}
+
+/**
+ * Build the Mulh replacement code for n / tv.
+ *
+ * Note that 'div' might be a Mod operation as well
+ */
+static ir_node *replace_div_by_mulh(ir_node *div, ir_tarval *tv)
+{
+ dbg_info *dbg = get_irn_dbg_info(div);
+ ir_node *n = get_binop_left(div);
+ ir_node *block = get_irn_n(div, -1);
+ ir_mode *mode = get_irn_mode(n);
+ int bits = get_mode_size_bits(mode);
+ ir_node *q, *t, *c;
+
+ /* Beware: do not transform bad code */
+ if (is_Bad(n) || is_Bad(block))
+ return div;
+
+ if (mode_is_signed(mode)) {
+ ir_graph *irg = get_irn_irg(div);
+ struct ms mag = magic(tv);
+
+ /* generate the Mulh instruction */
+ c = new_r_Const(irg, mag.M);
+ q = new_rd_Mulh(dbg, block, n, c, mode);
+
+ /* do we need an Add or Sub */
+ if (mag.need_add)
+ q = new_rd_Add(dbg, block, q, n, mode);
+ else if (mag.need_sub)
+ q = new_rd_Sub(dbg, block, q, n, mode);
+
+ /* Do we need the shift */
+ if (mag.s > 0) {
+ c = new_r_Const_long(irg, mode_Iu, mag.s);
+ q = new_rd_Shrs(dbg, block, q, c, mode);
+ }
+
+ /* final */
+ c = new_r_Const_long(irg, mode_Iu, bits - 1);
+ t = new_rd_Shr(dbg, block, q, c, mode);
+
+ q = new_rd_Add(dbg, block, q, t, mode);
+ } else {
+ struct mu mag = magicu(tv);
+ ir_node *c;
+ ir_graph *irg = get_irn_irg(div);
+
+ /* generate the Mulh instruction */
+ c = new_r_Const(irg, mag.M);
+ q = new_rd_Mulh(dbg, block, n, c, mode);
+
+ if (mag.need_add) {
+ if (mag.s > 0) {
+ /* use the GM scheme */
+ t = new_rd_Sub(dbg, block, n, q, mode);
+
+ c = new_r_Const(irg, get_mode_one(mode_Iu));
+ t = new_rd_Shr(dbg, block, t, c, mode);
+
+ t = new_rd_Add(dbg, block, t, q, mode);
+
+ c = new_r_Const_long(irg, mode_Iu, mag.s - 1);
+ q = new_rd_Shr(dbg, block, t, c, mode);
+ } else {
+ /* use the default scheme */
+ q = new_rd_Add(dbg, block, q, n, mode);
+ }
+ } else if (mag.s > 0) { /* default scheme, shift needed */
+ c = new_r_Const_long(irg, mode_Iu, mag.s);
+ q = new_rd_Shr(dbg, block, q, c, mode);
+ }
+ }
+ return q;
+}
+
+/* Replace Divs with Shifts and Add/Subs and Mulh. */
+ir_node *arch_dep_replace_div_by_const(ir_node *irn)
+{
+ const ir_settings_arch_dep_t *params = be_get_backend_param()->dep_param;
+ ir_node *res = irn;
+
+ /* If the architecture dependent optimizations were not initialized
+ or this optimization was not enabled. */
+ if (params == NULL || (opts & arch_dep_div_by_const) == 0)
+ return irn;
+
+ if (is_Div(irn)) {
+ ir_node *c = get_Div_right(irn);
+ ir_node *block, *left;
+ ir_mode *mode;
+ ir_tarval *tv, *ntv;
+ dbg_info *dbg;
+ int n, bits;
+ int k;
+ int n_flag = 0;
+
+ if (! is_Const(c))
+ return irn;
- /* If we have subs, we cannot do sequential. */
- if(1 /* also_use_subs */) {
- if(n > 0) {
- ir_node *curr = NULL;
+ tv = get_Const_tarval(c);
- i = n - 1;
+ /* check for division by zero */
+ if (tarval_is_null(tv))
+ return irn;
- do {
- int curr_shift = shifts[i];
- int sub = curr_shift < 0;
- int amount = abs(curr_shift) - 1;
- ir_node *aux = operand;
+ left = get_Div_left(irn);
+ mode = get_irn_mode(left);
+ /* can only handle integer Div's */
+ if (!mode_is_int(mode))
+ return irn;
- assert(amount >= 0 && "What is a negative shift??");
+ block = get_irn_n(irn, -1);
+ dbg = get_irn_dbg_info(irn);
- if(amount != 0) {
- tarval *shift_amount = new_tarval_from_long(amount, mode_Iu);
- ir_node *cnst = new_r_Const(current_ir_graph, block, mode_Iu, shift_amount);
- aux = new_r_Shl(current_ir_graph, block, operand, cnst, mode);
- }
+ bits = get_mode_size_bits(mode);
+ n = (bits + 7) / 8;
- if(curr) {
- if(sub)
- curr = new_r_Sub(current_ir_graph, block, curr, aux, mode);
- else
- curr = new_r_Add(current_ir_graph, block, curr, aux, mode);
- } else
- curr = aux;
+ k = -1;
+ if (mode_is_signed(mode)) {
+ /* for signed divisions, the algorithm works for a / -2^k by negating the result */
+ ntv = tarval_neg(tv);
+ n_flag = 1;
+ k = tv_ld2(ntv, n);
+ }
+
+ if (k < 0) {
+ n_flag = 0;
+ k = tv_ld2(tv, n);
+ }
- } while(--i >= 0);
+ if (k >= 0) { /* division by 2^k or -2^k */
+ ir_graph *irg = get_irn_irg(irn);
+ if (mode_is_signed(mode)) {
+ ir_node *k_node;
+ ir_node *curr = left;
- res = curr;
+ /* create the correction code for signed values only if there might be a remainder */
+ if (! get_Div_no_remainder(irn)) {
+ if (k != 1) {
+ k_node = new_r_Const_long(irg, mode_Iu, k - 1);
+ curr = new_rd_Shrs(dbg, block, left, k_node, mode);
}
+
+ k_node = new_r_Const_long(irg, mode_Iu, bits - k);
+ curr = new_rd_Shr(dbg, block, curr, k_node, mode);
+
+ curr = new_rd_Add(dbg, block, left, curr, mode);
+ } else {
+ k_node = left;
}
-#ifdef DEB
- {
- const char *prefix = "";
- for(i = 0; i < n; i++) {
- fprintf(stderr, "%s%d", prefix, shifts[i]);
- prefix = ", ";
- }
- fprintf(stderr, "\n");
+ k_node = new_r_Const_long(irg, mode_Iu, k);
+ res = new_rd_Shrs(dbg, block, curr, k_node, mode);
+
+ if (n_flag) { /* negate the result */
+ ir_node *k_node;
+
+ k_node = new_r_Const(irg, get_mode_null(mode));
+ res = new_rd_Sub(dbg, block, k_node, res, mode);
}
-#endif
+ } else { /* unsigned case */
+ ir_node *k_node;
+ k_node = new_r_Const_long(irg, mode_Iu, k);
+ res = new_rd_Shr(dbg, block, left, k_node, mode);
}
-
- if(bitstr)
- free(bitstr);
+ } else {
+ /* other constant */
+ if (allow_Mulh(params, mode))
+ res = replace_div_by_mulh(irn, tv);
}
-
}
+ if (res != irn)
+ hook_arch_dep_replace_division_by_const(irn);
+
return res;
}
+/* Replace Mods with Shifts and Add/Subs and Mulh. */
+ir_node *arch_dep_replace_mod_by_const(ir_node *irn)
+{
+ const ir_settings_arch_dep_t *params = be_get_backend_param()->dep_param;
+ ir_node *res = irn;
-static const arch_dep_params_t default_params = {
- 1, /* also use subs */
- 4, /* maximum shifts */
- 31 /* maximum shift amount */
-};
+ /* If the architecture dependent optimizations were not initialized
+ or this optimization was not enabled. */
+ if (params == NULL || (opts & arch_dep_mod_by_const) == 0)
+ return irn;
+
+ if (is_Mod(irn)) {
+ ir_node *c = get_Mod_right(irn);
+ ir_node *block, *left;
+ ir_mode *mode;
+ ir_tarval *tv, *ntv;
+ dbg_info *dbg;
+ int n, bits;
+ int k;
+
+ if (! is_Const(c))
+ return irn;
+
+ tv = get_Const_tarval(c);
+
+ /* check for division by zero */
+ if (tarval_is_null(tv))
+ return irn;
+
+ left = get_Mod_left(irn);
+ mode = get_irn_mode(left);
+ block = get_irn_n(irn, -1);
+ dbg = get_irn_dbg_info(irn);
+ bits = get_mode_size_bits(mode);
+ n = (bits + 7) / 8;
+
+ k = -1;
+ if (mode_is_signed(mode)) {
+ /* for signed divisions, the algorithm works for a / -2^k by negating the result */
+ ntv = tarval_neg(tv);
+ k = tv_ld2(ntv, n);
+ }
+
+ if (k < 0) {
+ k = tv_ld2(tv, n);
+ }
+
+ if (k >= 0) {
+ ir_graph *irg = get_irn_irg(irn);
+ /* division by 2^k or -2^k:
+ * we use "modulus" here, so x % y == x % -y that's why is no difference between the case 2^k and -2^k
+ */
+ if (mode_is_signed(mode)) {
+ ir_node *k_node;
+ ir_node *curr = left;
+
+ if (k != 1) {
+ k_node = new_r_Const_long(irg, mode_Iu, k - 1);
+ curr = new_rd_Shrs(dbg, block, left, k_node, mode);
+ }
+
+ k_node = new_r_Const_long(irg, mode_Iu, bits - k);
+ curr = new_rd_Shr(dbg, block, curr, k_node, mode);
+
+ curr = new_rd_Add(dbg, block, left, curr, mode);
+
+ k_node = new_r_Const_long(irg, mode, (-1) << k);
+ curr = new_rd_And(dbg, block, curr, k_node, mode);
+
+ res = new_rd_Sub(dbg, block, left, curr, mode);
+ } else { /* unsigned case */
+ ir_node *k_node;
+
+ k_node = new_r_Const_long(irg, mode, (1 << k) - 1);
+ res = new_rd_And(dbg, block, left, k_node, mode);
+ }
+ } else {
+ /* other constant */
+ if (allow_Mulh(params, mode)) {
+ res = replace_div_by_mulh(irn, tv);
+
+ res = new_rd_Mul(dbg, block, res, c, mode);
-const arch_dep_params_t *arch_dep_default_factory(void) {
- return &default_params;
+ /* res = arch_dep_mul_to_shift(res); */
+
+ res = new_rd_Sub(dbg, block, left, res, mode);
+ }
+ }
+ }
+
+ if (res != irn)
+ hook_arch_dep_replace_division_by_const(irn);
+
+ return res;
}
projects / libfirm / blobdiff