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#include "all.h"
#include <stdbool.h>
#include <stddef.h>
static void mark_changed(bool *ch) { *ch = true; }
static bool is_arith(ast_type_e t) { return t == AST_INC || t == AST_DEC; }
static bool is_ptr(ast_type_e t) {
return t == AST_PTR_INC || t == AST_PTR_DEC;
}
static int node_signed_value(const ast_node_t *n) {
if (n->type == AST_DEC || n->type == AST_PTR_DEC)
return -n->val;
return n->val;
}
static void set_arith_node(ast_node_t *n, int v) {
if (v > 0) {
n->type = AST_INC;
n->val = v;
} else {
n->type = AST_DEC;
n->val = -v;
}
}
static void set_ptr_node(ast_node_t *n, int v) {
if (v > 0) {
n->type = AST_PTR_INC;
n->val = v;
} else {
n->type = AST_PTR_DEC;
n->val = -v;
}
}
static void optimize_list(ast_node_t **head, bool *ch);
static void optimize_loop_node(ast_node_t *n, bool *ch) {
if (!n || n->type != AST_LOOP)
return;
if (n->children.len == 0 || n->children._data[0] == NULL) {
n->children.len = 0;
return;
}
optimize_list(&n->children._data[0], ch);
if (n->children._data[0] == NULL) {
n->children.len = 0;
return;
}
if (n->children.len == 1) {
ast_node_t *c = n->children._data[0];
if ((c->type == AST_INC || c->type == AST_DEC) && c->val == 1) {
n->type = AST_CLEAR;
n->val = 0;
n->children.len = 0;
n->children._data[0] = NULL;
mark_changed(ch);
}
}
}
static void optimize_list(ast_node_t **head, bool *ch) {
ast_node_t **p = head;
while (*p) {
ast_node_t *n = *p;
if (n->type == AST_LOOP) {
optimize_loop_node(n, ch);
if (n->type == AST_LOOP && n->children.len == 0) {
*p = n->next;
mark_changed(ch);
continue;
}
}
if (*p && (*p)->next) {
ast_node_t *a = *p;
ast_node_t *b = a->next;
if (is_arith(a->type) && is_arith(b->type)) {
int v = node_signed_value(a) + node_signed_value(b);
if (v == 0) {
a->next = b->next;
mark_changed(ch);
continue;
}
set_arith_node(a, v);
a->next = b->next;
mark_changed(ch);
continue;
}
if (is_ptr(a->type) && is_ptr(b->type)) {
int v = node_signed_value(a) + node_signed_value(b);
if (v == 0) {
a->next = b->next;
mark_changed(ch);
continue;
}
set_ptr_node(a, v);
a->next = b->next;
mark_changed(ch);
continue;
}
}
p = &(*p)->next;
}
}
ast_node_t *optimize_ast(ast_node_t *ast) {
bool ch;
do {
ch = false;
optimize_list(&ast, &ch);
} while (ch);
return ast;
}
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