diff options
| -rw-r--r-- | peephole.c | 13 |
1 files changed, 13 insertions, 0 deletions
@@ -196,6 +196,7 @@ static inline int node_sub_add_equiv(Node *a, Node *b) { static int node_equiv_input(Node *a, Node *b); +/* TODO: separate out equivalence as in complete identity vs. just same value */ static int node_equiv(Node *a, Node *b) { /* will doing this recursively be too slow? */ if (a == b) return 1; @@ -217,6 +218,7 @@ static inline int node_known_not_equiv_ord(Node *a, Node *b) { return 0; } static inline int node_known_not_equiv(Node *a, Node *b) { + if (node_cmp_incompat(a->op, b->op) && node_equiv_input(a, b)) return 1; return node_known_not_equiv_ord(a, b) || node_known_not_equiv_ord(b, a); } @@ -486,6 +488,10 @@ zero_no_effect: if (node_eql_i64(CAR(n), 0)) return CDR(n); if (BOOL_EQ(CDR(n), 1)) return CAR(n); if (BOOL_EQ(CDR(n), 0)) return NODE(N_OP_NOT, CAR(n)); if (T(CAR(n), N_OP_NOT) && node_equiv(CDR(n), CAAR(n))) return node_new_lit_bool(p, 0); + if (((T(CAR(n), N_CMP_LTE) && T(CDR(n), N_CMP_GTE)) || (T(CAR(n), N_CMP_GTE) && T(CDR(n), N_CMP_LTE))) + && node_equiv_input(CAR(n), CDR(n))) { + return NODE(N_CMP_EQL, CAAR(n), CADR(n)); + } break; case N_CMP_NEQ: if (same) return node_new_lit_bool(p, 0); @@ -560,6 +566,13 @@ zero_no_effect: if (node_eql_i64(CAR(n), 0)) return CDR(n); } } break; + case N_OP_SHL: + case N_OP_SHR: + /* a (<< | >>) 0 -> a */ + /* 0 (<< | >>) a -> 0 */ + if (node_eql_i64(CDR(n), 0) || node_eql_i64(CAR(n), 0)) return CAR(n); + break; + default: break; } |