| /* |
| * Simplify - do instruction simplification before CSE |
| * |
| * Copyright (C) 2004 Linus Torvalds |
| */ |
| |
| /// |
| // Instruction simplification |
| // -------------------------- |
| // |
| // Notation |
| // ^^^^^^^^ |
| // The following conventions are used to describe the simplications: |
| // * Uppercase letters are reserved for constants: |
| // * `M` for a constant mask, |
| // * `S` for a constant shift, |
| // * `N` for a constant number of bits (usually other than a shift), |
| // * `C` or 'K' for others constants. |
| // * Lowercase letters `a`, `b`, `x`, `y`, ... are used for non-constants |
| // or when it doesn't matter if the pseudo is a constant or not. |
| // * Primes are used if needed to distinguish symbols (`M`, `M'`, ...). |
| // * Expressions or sub-expressions involving only constants are |
| // understood to be evaluated. |
| // * `$mask(N)` is used for `((1 << N) -1)` |
| // * `$trunc(x, N)` is used for `(x & $mask(N))` |
| // * Expressions like `(-1 << S)`, `(-1 >> S)` and others formulae are |
| // understood to be truncated to the size of the current instruction |
| // (needed, since in general this size is not the same as the one used |
| // by sparse for the evaluation of arithmetic operations). |
| // * `TRUNC(x, N)` is used for a truncation *to* a size of `N` bits |
| // * `ZEXT(x, N)` is used for a zero-extension *from* a size of `N` bits |
| // * `OP(x, C)` is used to represent some generic operation using a constant, |
| // including when the constant is implicit (e.g. `TRUNC(x, N)`). |
| // * `MASK(x, M)` is used to respresent a 'masking' instruction: |
| // - `AND(x, M)` |
| // - `LSR(x, S)`, with `M` = (-1 << S) |
| // - `SHL(x, S)`, with `M` = (-1 >> S) |
| // - `TRUNC(x, N)`, with `M` = $mask(N) |
| // - `ZEXT(x, N)`, with `M` = $mask(N) |
| // * `SHIFT(x, S)` is used for `LSR(x, S)` or `SHL(x, S)`. |
| |
| #include <assert.h> |
| |
| #include "parse.h" |
| #include "expression.h" |
| #include "linearize.h" |
| #include "flow.h" |
| #include "symbol.h" |
| |
| /// |
| // Utilities |
| // ^^^^^^^^^ |
| |
| /// |
| // find the trivial parent for a phi-source |
| static struct basic_block *phi_parent(struct basic_block *source, pseudo_t pseudo) |
| { |
| /* Can't go upwards if the pseudo is defined in the bb it came from.. */ |
| if (pseudo->type == PSEUDO_REG) { |
| struct instruction *def = pseudo->def; |
| if (def->bb == source) |
| return source; |
| } |
| if (bb_list_size(source->children) != 1 || bb_list_size(source->parents) != 1) |
| return source; |
| return first_basic_block(source->parents); |
| } |
| |
| /// |
| // copy the phi-node's phisrcs into to given array |
| // @return: 0 if the the list contained the expected |
| // number of element, a positive number if there was |
| // more than expected and a negative one if less. |
| // |
| // :note: we can't reuse a function like linearize_ptr_list() |
| // because any VOIDs in the phi-list must be ignored here |
| // as in this context they mean 'entry has been removed'. |
| static int get_phisources(struct instruction *sources[], int nbr, struct instruction *insn) |
| { |
| pseudo_t phi; |
| int i = 0; |
| |
| assert(insn->opcode == OP_PHI); |
| FOR_EACH_PTR(insn->phi_list, phi) { |
| struct instruction *def; |
| if (phi == VOID) |
| continue; |
| if (i >= nbr) |
| return 1; |
| def = phi->def; |
| assert(def->opcode == OP_PHISOURCE); |
| sources[i++] = def; |
| } END_FOR_EACH_PTR(phi); |
| return i - nbr; |
| } |
| |
| static int if_convert_phi(struct instruction *insn) |
| { |
| struct instruction *array[2]; |
| struct basic_block *parents[3]; |
| struct basic_block *bb, *bb1, *bb2, *source; |
| struct instruction *br; |
| pseudo_t p1, p2; |
| |
| bb = insn->bb; |
| if (get_phisources(array, 2, insn)) |
| return 0; |
| if (linearize_ptr_list((struct ptr_list *)bb->parents, (void **)parents, 3) != 2) |
| return 0; |
| p1 = array[0]->phi_src; |
| bb1 = array[0]->bb; |
| p2 = array[1]->phi_src; |
| bb2 = array[1]->bb; |
| |
| /* Only try the simple "direct parents" case */ |
| if ((bb1 != parents[0] || bb2 != parents[1]) && |
| (bb1 != parents[1] || bb2 != parents[0])) |
| return 0; |
| |
| /* |
| * See if we can find a common source for this.. |
| */ |
| source = phi_parent(bb1, p1); |
| if (source != phi_parent(bb2, p2)) |
| return 0; |
| |
| /* |
| * Cool. We now know that 'source' is the exclusive |
| * parent of both phi-nodes, so the exit at the |
| * end of it fully determines which one it is, and |
| * we can turn it into a select. |
| * |
| * HOWEVER, right now we only handle regular |
| * conditional branches. No multijumps or computed |
| * stuff. Verify that here. |
| */ |
| br = last_instruction(source->insns); |
| if (!br || br->opcode != OP_CBR) |
| return 0; |
| |
| assert(br->cond); |
| assert(br->bb_false); |
| |
| /* |
| * We're in business. Match up true/false with p1/p2. |
| */ |
| if (br->bb_true == bb2 || br->bb_false == bb1) { |
| pseudo_t p = p1; |
| p1 = p2; |
| p2 = p; |
| } |
| |
| /* |
| * OK, we can now replace that last |
| * |
| * br cond, a, b |
| * |
| * with the sequence |
| * |
| * setcc cond |
| * select pseudo, p1, p2 |
| * br cond, a, b |
| * |
| * and remove the phi-node. If it then |
| * turns out that 'a' or 'b' is entirely |
| * empty (common case), and now no longer |
| * a phi-source, we'll be able to simplify |
| * the conditional branch too. |
| */ |
| insert_select(source, br, insn, p1, p2); |
| kill_instruction(insn); |
| return REPEAT_CSE; |
| } |
| |
| /// |
| // detect trivial phi-nodes |
| // @insn: the phi-node |
| // @pseudo: the candidate resulting pseudo (NULL when starting) |
| // @return: the unique result if the phi-node is trivial, NULL otherwise |
| // |
| // A phi-node is trivial if it has a single possible result: |
| // * all operands are the same |
| // * the operands are themselves defined by a chain or cycle of phi-nodes |
| // and the set of all operands involved contains a single value |
| // not defined by these phi-nodes |
| // |
| // Since the result is unique, these phi-nodes can be removed. |
| static pseudo_t trivial_phi(pseudo_t pseudo, struct instruction *insn, struct pseudo_list **list) |
| { |
| pseudo_t target = insn->target; |
| pseudo_t phi; |
| |
| add_pseudo(list, target); |
| |
| FOR_EACH_PTR(insn->phi_list, phi) { |
| struct instruction *def; |
| pseudo_t src; |
| |
| if (phi == VOID) |
| continue; |
| def = phi->def; |
| if (!def->bb) |
| continue; |
| src = def->phi_src; // bypass OP_PHISRC & get the real source |
| if (src == VOID) |
| continue; |
| if (!pseudo) { |
| pseudo = src; |
| continue; |
| } |
| if (src == pseudo) |
| continue; |
| if (src == target) |
| continue; |
| if (DEF_OPCODE(def, src) == OP_PHI) { |
| if (pseudo_in_list(*list, src)) |
| continue; |
| if ((pseudo = trivial_phi(pseudo, def, list))) |
| continue; |
| } |
| return NULL; |
| } END_FOR_EACH_PTR(phi); |
| |
| return pseudo ? pseudo : VOID; |
| } |
| |
| static int clean_up_phi(struct instruction *insn) |
| { |
| struct pseudo_list *list = NULL; |
| pseudo_t pseudo; |
| |
| if ((pseudo = trivial_phi(NULL, insn, &list))) { |
| convert_instruction_target(insn, pseudo); |
| kill_instruction(insn); |
| return REPEAT_CSE; |
| } |
| |
| return if_convert_phi(insn); |
| } |
| |
| static int delete_pseudo_user_list_entry(struct pseudo_user_list **list, pseudo_t *entry, int count) |
| { |
| struct pseudo_user *pu; |
| |
| FOR_EACH_PTR(*list, pu) { |
| if (pu->userp == entry) { |
| MARK_CURRENT_DELETED(pu); |
| if (!--count) |
| goto out; |
| } |
| } END_FOR_EACH_PTR(pu); |
| assert(count <= 0); |
| out: |
| if (pseudo_user_list_empty(*list)) |
| *list = NULL; |
| return count; |
| } |
| |
| static inline void rem_usage(pseudo_t p, pseudo_t *usep, int kill) |
| { |
| if (has_use_list(p)) { |
| if (p->type == PSEUDO_SYM) |
| repeat_phase |= REPEAT_SYMBOL_CLEANUP; |
| delete_pseudo_user_list_entry(&p->users, usep, 1); |
| if (kill && !p->users) |
| kill_instruction(p->def); |
| } |
| } |
| |
| static inline void remove_usage(pseudo_t p, pseudo_t *usep) |
| { |
| rem_usage(p, usep, 1); |
| } |
| |
| void kill_use(pseudo_t *usep) |
| { |
| if (usep) { |
| pseudo_t p = *usep; |
| *usep = VOID; |
| rem_usage(p, usep, 1); |
| } |
| } |
| |
| // Like kill_use() but do not (recursively) kill dead instructions |
| void remove_use(pseudo_t *usep) |
| { |
| pseudo_t p = *usep; |
| *usep = VOID; |
| rem_usage(p, usep, 0); |
| } |
| |
| static void kill_use_list(struct pseudo_list *list) |
| { |
| pseudo_t p; |
| FOR_EACH_PTR(list, p) { |
| if (p == VOID) |
| continue; |
| kill_use(THIS_ADDRESS(p)); |
| } END_FOR_EACH_PTR(p); |
| } |
| |
| /// |
| // kill an instruction |
| // @insn: the instruction to be killed |
| // @force: if unset, the normal case, the instruction is not killed |
| // if not free of possible side-effect; if set the instruction |
| // is unconditionally killed. |
| // |
| // The killed instruction is removed from its BB and the usage |
| // of all its operands are removed. The instruction is also |
| // marked as killed by setting its ->bb to NULL. |
| int kill_insn(struct instruction *insn, int force) |
| { |
| if (!insn || !insn->bb) |
| return 0; |
| |
| switch (insn->opcode) { |
| case OP_SEL: |
| case OP_RANGE: |
| kill_use(&insn->src3); |
| /* fall through */ |
| |
| case OP_BINARY ... OP_BINCMP_END: |
| kill_use(&insn->src2); |
| /* fall through */ |
| |
| case OP_UNOP ... OP_UNOP_END: |
| case OP_SETVAL: |
| case OP_SLICE: |
| kill_use(&insn->src1); |
| break; |
| |
| case OP_PHI: |
| kill_use_list(insn->phi_list); |
| break; |
| case OP_PHISOURCE: |
| kill_use(&insn->phi_src); |
| break; |
| |
| case OP_SYMADDR: |
| kill_use(&insn->src); |
| repeat_phase |= REPEAT_SYMBOL_CLEANUP; |
| break; |
| |
| case OP_CBR: |
| case OP_SWITCH: |
| case OP_COMPUTEDGOTO: |
| kill_use(&insn->cond); |
| break; |
| |
| case OP_CALL: |
| if (!force) { |
| /* a "pure" function can be killed too */ |
| if (!(insn->func->type == PSEUDO_SYM)) |
| return 0; |
| if (!(insn->func->sym->ctype.modifiers & MOD_PURE)) |
| return 0; |
| } |
| kill_use_list(insn->arguments); |
| if (insn->func->type == PSEUDO_REG) |
| kill_use(&insn->func); |
| break; |
| |
| case OP_LOAD: |
| if (!force && insn->is_volatile) |
| return 0; |
| kill_use(&insn->src); |
| break; |
| |
| case OP_STORE: |
| if (!force) |
| return 0; |
| kill_use(&insn->src); |
| kill_use(&insn->target); |
| break; |
| |
| case OP_ENTRY: |
| /* ignore */ |
| return 0; |
| |
| case OP_BR: |
| case OP_SETFVAL: |
| default: |
| break; |
| } |
| |
| insn->bb = NULL; |
| return repeat_phase |= REPEAT_CSE; |
| } |
| |
| /// |
| // kill trivially dead instructions |
| static int dead_insn(struct instruction *insn, pseudo_t *src1, pseudo_t *src2, pseudo_t *src3) |
| { |
| if (has_users(insn->target)) |
| return 0; |
| |
| insn->bb = NULL; |
| kill_use(src1); |
| kill_use(src2); |
| kill_use(src3); |
| return REPEAT_CSE; |
| } |
| |
| static inline bool has_target(struct instruction *insn) |
| { |
| return opcode_table[insn->opcode].flags & OPF_TARGET; |
| } |
| |
| void remove_dead_insns(struct entrypoint *ep) |
| { |
| struct basic_block *bb; |
| |
| FOR_EACH_PTR_REVERSE(ep->bbs, bb) { |
| struct instruction *insn; |
| FOR_EACH_PTR_REVERSE(bb->insns, insn) { |
| if (!insn->bb) |
| continue; |
| if (!has_target(insn)) |
| continue; |
| if (!has_users(insn->target)) |
| kill_instruction(insn); |
| } END_FOR_EACH_PTR_REVERSE(insn); |
| } END_FOR_EACH_PTR_REVERSE(bb); |
| } |
| |
| static inline int constant(pseudo_t pseudo) |
| { |
| return pseudo->type == PSEUDO_VAL; |
| } |
| |
| /// |
| // replace the operand of an instruction |
| // @insn: the instruction |
| // @pp: the address of the instruction's operand |
| // @new: the new value for the operand |
| // @return: REPEAT_CSE. |
| static inline int replace_pseudo(struct instruction *insn, pseudo_t *pp, pseudo_t new) |
| { |
| pseudo_t old = *pp; |
| use_pseudo(insn, new, pp); |
| remove_usage(old, pp); |
| return REPEAT_CSE; |
| } |
| |
| static int replace_with_pseudo(struct instruction *insn, pseudo_t pseudo) |
| { |
| convert_instruction_target(insn, pseudo); |
| |
| switch (insn->opcode) { |
| case OP_SEL: |
| case OP_RANGE: |
| kill_use(&insn->src3); |
| case OP_BINARY ... OP_BINCMP_END: |
| kill_use(&insn->src2); |
| case OP_UNOP ... OP_UNOP_END: |
| case OP_SYMADDR: |
| kill_use(&insn->src1); |
| break; |
| |
| default: |
| assert(0); |
| } |
| insn->bb = NULL; |
| return REPEAT_CSE; |
| } |
| |
| static inline int def_opcode(pseudo_t p) |
| { |
| if (p->type != PSEUDO_REG) |
| return OP_BADOP; |
| return p->def->opcode; |
| } |
| |
| static unsigned int value_size(long long value) |
| { |
| value >>= 8; |
| if (!value) |
| return 8; |
| value >>= 8; |
| if (!value) |
| return 16; |
| value >>= 16; |
| if (!value) |
| return 32; |
| return 64; |
| } |
| |
| /// |
| // try to determine the maximum size of bits in a pseudo |
| // |
| // Right now this only follow casts and constant values, but we |
| // could look at things like AND instructions, etc. |
| static unsigned int operand_size(struct instruction *insn, pseudo_t pseudo) |
| { |
| unsigned int size = insn->size; |
| |
| if (pseudo->type == PSEUDO_REG) { |
| struct instruction *src = pseudo->def; |
| if (src && src->opcode == OP_ZEXT && src->orig_type) { |
| unsigned int orig_size = src->orig_type->bit_size; |
| if (orig_size < size) |
| size = orig_size; |
| } |
| } |
| if (pseudo->type == PSEUDO_VAL) { |
| unsigned int orig_size = value_size(pseudo->value); |
| if (orig_size < size) |
| size = orig_size; |
| } |
| return size; |
| } |
| |
| static pseudo_t eval_insn(struct instruction *insn) |
| { |
| /* FIXME! Verify signs and sizes!! */ |
| unsigned int size = insn->size; |
| long long left = insn->src1->value; |
| long long right = insn->src2->value; |
| unsigned long long ul, ur; |
| long long res, mask, bits; |
| |
| mask = 1ULL << (size-1); |
| bits = mask | (mask-1); |
| |
| if (left & mask) |
| left |= ~bits; |
| if (right & mask) |
| right |= ~bits; |
| ul = left & bits; |
| ur = right & bits; |
| |
| switch (insn->opcode) { |
| case OP_ADD: |
| res = left + right; |
| break; |
| case OP_SUB: |
| res = left - right; |
| break; |
| case OP_MUL: |
| res = ul * ur; |
| break; |
| case OP_DIVU: |
| if (!ur) |
| goto undef; |
| res = ul / ur; |
| break; |
| case OP_DIVS: |
| if (!right) |
| goto undef; |
| if (left == mask && right == -1) |
| goto undef; |
| res = left / right; |
| break; |
| case OP_MODU: |
| if (!ur) |
| goto undef; |
| res = ul % ur; |
| break; |
| case OP_MODS: |
| if (!right) |
| goto undef; |
| if (left == mask && right == -1) |
| goto undef; |
| res = left % right; |
| break; |
| case OP_SHL: |
| if (ur >= size) |
| goto undef; |
| res = left << right; |
| break; |
| case OP_LSR: |
| if (ur >= size) |
| goto undef; |
| res = ul >> ur; |
| break; |
| case OP_ASR: |
| if (ur >= size) |
| goto undef; |
| res = left >> right; |
| break; |
| /* Logical */ |
| case OP_AND: |
| res = left & right; |
| break; |
| case OP_OR: |
| res = left | right; |
| break; |
| case OP_XOR: |
| res = left ^ right; |
| break; |
| |
| /* Binary comparison */ |
| case OP_SET_EQ: |
| res = left == right; |
| break; |
| case OP_SET_NE: |
| res = left != right; |
| break; |
| case OP_SET_LE: |
| res = left <= right; |
| break; |
| case OP_SET_GE: |
| res = left >= right; |
| break; |
| case OP_SET_LT: |
| res = left < right; |
| break; |
| case OP_SET_GT: |
| res = left > right; |
| break; |
| case OP_SET_B: |
| res = ul < ur; |
| break; |
| case OP_SET_A: |
| res = ul > ur; |
| break; |
| case OP_SET_BE: |
| res = ul <= ur; |
| break; |
| case OP_SET_AE: |
| res = ul >= ur; |
| break; |
| default: |
| return NULL; |
| } |
| res &= bits; |
| |
| return value_pseudo(res); |
| |
| undef: |
| return NULL; |
| } |
| |
| /// |
| // Simplifications |
| // ^^^^^^^^^^^^^^^ |
| |
| /// |
| // try to simplify MASK(OR(AND(x, M'), b), M) |
| // @insn: the masking instruction |
| // @mask: the associated mask (M) |
| // @ora: one of the OR's operands, guaranteed to be PSEUDO_REG |
| // @orb: the other OR's operand |
| // @return: 0 if no changes have been made, one or more REPEAT_* flags otherwise. |
| static int simplify_mask_or_and(struct instruction *insn, unsigned long long mask, |
| pseudo_t ora, pseudo_t orb) |
| { |
| unsigned long long omask, nmask; |
| struct instruction *and = ora->def; |
| pseudo_t src2 = and->src2; |
| |
| if (and->opcode != OP_AND) |
| return 0; |
| if (!constant(src2)) |
| return 0; |
| omask = src2->value; |
| nmask = omask & mask; |
| if (nmask == 0) { |
| // if (M' & M) == 0: ((a & M') | b) -> b |
| return replace_pseudo(insn, &insn->src1, orb); |
| } |
| if (multi_users(insn->src1)) |
| return 0; // can't modify anything inside the OR |
| if (nmask == mask) { |
| struct instruction *or = insn->src1->def; |
| pseudo_t *arg = (ora == or->src1) ? &or->src1 : &or->src2; |
| // if (M' & M) == M: ((a & M') | b) -> (a | b) |
| return replace_pseudo(or, arg, and->src1); |
| } |
| if (nmask != omask && !multi_users(ora)) { |
| // if (M' & M) != M': AND(a, M') -> AND(a, (M' & M)) |
| and->src2 = value_pseudo(nmask); |
| return REPEAT_CSE; |
| } |
| return 0; |
| } |
| |
| /// |
| // try to simplify MASK(OR(a, b), M) |
| // @insn: the masking instruction |
| // @mask: the associated mask (M) |
| // @or: the OR instruction |
| // @return: 0 if no changes have been made, one or more REPEAT_* flags otherwise. |
| static int simplify_mask_or(struct instruction *insn, unsigned long long mask, struct instruction *or) |
| { |
| pseudo_t src1 = or->src1; |
| pseudo_t src2 = or->src2; |
| int rc; |
| |
| if (src1->type == PSEUDO_REG) { |
| if ((rc = simplify_mask_or_and(insn, mask, src1, src2))) |
| return rc; |
| } |
| if (src2->type == PSEUDO_REG) { |
| if ((rc = simplify_mask_or_and(insn, mask, src2, src1))) |
| return rc; |
| } else if (src2->type == PSEUDO_VAL) { |
| unsigned long long oval = src2->value; |
| unsigned long long nval = oval & mask; |
| // Try to simplify: |
| // MASK(OR(x, C), M) |
| if (nval == 0) { |
| // if (C & M) == 0: OR(x, C) -> x |
| return replace_pseudo(insn, &insn->src1, src1); |
| } |
| if (nval == mask) { |
| // if (C & M) == M: OR(x, C) -> M |
| return replace_pseudo(insn, &insn->src1, value_pseudo(mask)); |
| } |
| if (nval != oval && !multi_users(or->target)) { |
| // if (C & M) != C: OR(x, C) -> OR(x, (C & M)) |
| return replace_pseudo(or, &or->src2, value_pseudo(nval)); |
| } |
| } |
| return 0; |
| } |
| |
| /// |
| // try to simplify MASK(SHIFT(OR(a, b), S), M) |
| // @sh: the shift instruction |
| // @or: the OR instruction |
| // @mask: the mask associated to MASK (M): |
| // @return: 0 if no changes have been made, one or more REPEAT_* flags otherwise. |
| static int simplify_mask_shift_or(struct instruction *sh, struct instruction *or, unsigned long long mask) |
| { |
| unsigned long long smask = bits_mask(sh->size); |
| int shift = sh->src2->value; |
| |
| if (sh->opcode == OP_LSR) |
| mask <<= shift; |
| else |
| mask >>= shift; |
| return simplify_mask_or(sh, smask & mask, or); |
| } |
| |
| static int simplify_mask_shift(struct instruction *sh, unsigned long long mask) |
| { |
| struct instruction *inner; |
| |
| if (!constant(sh->src2) || sh->tainted) |
| return 0; |
| switch (DEF_OPCODE(inner, sh->src1)) { |
| case OP_OR: |
| if (!multi_users(sh->target)) |
| return simplify_mask_shift_or(sh, inner, mask); |
| break; |
| } |
| return 0; |
| } |
| |
| static long long check_shift_count(struct instruction *insn, unsigned long long uval) |
| { |
| unsigned int size = insn->size; |
| long long sval = uval; |
| |
| if (uval < size) |
| return uval; |
| |
| sval = sign_extend_safe(sval, size); |
| sval = sign_extend_safe(sval, bits_in_int); |
| if (sval < 0) |
| insn->src2 = value_pseudo(sval); |
| if (insn->tainted) |
| return sval; |
| |
| if (sval < 0 && Wshift_count_negative) |
| warning(insn->pos, "shift count is negative (%lld)", sval); |
| if (sval > 0 && Wshift_count_overflow) { |
| struct symbol *ctype = insn->type; |
| const char *tname; |
| if (ctype->type == SYM_NODE) |
| ctype = ctype->ctype.base_type; |
| tname = show_typename(ctype); |
| warning(insn->pos, "shift too big (%llu) for type %s", sval, tname); |
| } |
| insn->tainted = 1; |
| return sval; |
| } |
| |
| static int simplify_shift(struct instruction *insn, pseudo_t pseudo, long long value) |
| { |
| struct instruction *def; |
| unsigned long long mask, omask, nmask; |
| unsigned long long nval; |
| unsigned int size; |
| pseudo_t src2; |
| |
| if (!value) |
| return replace_with_pseudo(insn, pseudo); |
| value = check_shift_count(insn, value); |
| if (value < 0) |
| return 0; |
| |
| size = insn->size; |
| switch (insn->opcode) { |
| case OP_ASR: |
| if (value >= size) |
| return 0; |
| if (pseudo->type != PSEUDO_REG) |
| break; |
| def = pseudo->def; |
| switch (def->opcode) { |
| case OP_LSR: |
| case OP_ASR: |
| if (def == insn) // cyclic DAG! |
| break; |
| src2 = def->src2; |
| if (src2->type != PSEUDO_VAL) |
| break; |
| nval = src2->value; |
| if (nval > insn->size || nval == 0) |
| break; |
| value += nval; |
| if (def->opcode == OP_LSR) |
| insn->opcode = OP_LSR; |
| else if (value >= size) |
| value = size - 1; |
| goto new_value; |
| |
| case OP_ZEXT: |
| // transform: |
| // zext.N %t <- (O) %a |
| // asr.N %r <- %t, C |
| // into |
| // zext.N %t <- (O) %a |
| // lsr.N %r <- %t, C |
| insn->opcode = OP_LSR; |
| return REPEAT_CSE; |
| } |
| break; |
| case OP_LSR: |
| size = operand_size(insn, pseudo); |
| if (value >= size) |
| goto zero; |
| switch(DEF_OPCODE(def, pseudo)) { |
| case OP_AND: |
| // replace (A & M) >> S |
| // by (A >> S) & (M >> S) |
| if (!constant(def->src2)) |
| break; |
| mask = bits_mask(insn->size - value) << value; |
| omask = def->src2->value; |
| nmask = omask & mask; |
| if (nmask == 0) |
| return replace_with_pseudo(insn, value_pseudo(0)); |
| if (nmask == mask) |
| return replace_pseudo(insn, &insn->src1, def->src1); |
| if (nbr_users(pseudo) > 1) |
| break; |
| def->opcode = OP_LSR; |
| def->src2 = insn->src2; |
| insn->opcode = OP_AND; |
| insn->src2 = value_pseudo(omask >> value); |
| return REPEAT_CSE; |
| case OP_LSR: |
| goto case_shift_shift; |
| case OP_OR: |
| mask = bits_mask(size); |
| return simplify_mask_shift_or(insn, def, mask); |
| case OP_SHL: |
| // replace ((x << S) >> S) |
| // by (x & (-1 >> S)) |
| if (def->src2 != insn->src2) |
| break; |
| mask = bits_mask(insn->size - value); |
| goto replace_mask; |
| } |
| break; |
| case OP_SHL: |
| if (value >= size) |
| goto zero; |
| switch(DEF_OPCODE(def, pseudo)) { |
| case OP_AND: |
| // simplify (A & M) << S |
| if (!constant(def->src2)) |
| break; |
| mask = bits_mask(insn->size) >> value; |
| omask = def->src2->value; |
| nmask = omask & mask; |
| if (nmask == 0) |
| return replace_with_pseudo(insn, value_pseudo(0)); |
| if (nmask == mask) |
| return replace_pseudo(insn, &insn->src1, def->src1); |
| // do not simplify into ((A << S) & (M << S)) |
| break; |
| case OP_LSR: |
| // replace ((x >> S) << S) |
| // by (x & (-1 << S)) |
| if (def->src2 != insn->src2) |
| break; |
| mask = bits_mask(insn->size - value) << value; |
| goto replace_mask; |
| case OP_OR: |
| mask = bits_mask(size); |
| return simplify_mask_shift_or(insn, def, mask); |
| case OP_SHL: |
| case_shift_shift: // also for LSR - LSR |
| if (def == insn) // cyclic DAG! |
| break; |
| src2 = def->src2; |
| if (src2->type != PSEUDO_VAL) |
| break; |
| nval = src2->value; |
| if (nval > insn->size) |
| break; |
| value += nval; |
| goto new_value; |
| } |
| break; |
| } |
| return 0; |
| |
| new_value: |
| if (value < size) { |
| insn->src2 = value_pseudo(value); |
| return replace_pseudo(insn, &insn->src1, pseudo->def->src1); |
| } |
| zero: |
| return replace_with_pseudo(insn, value_pseudo(0)); |
| replace_mask: |
| insn->opcode = OP_AND; |
| insn->src2 = value_pseudo(mask); |
| return replace_pseudo(insn, &insn->src1, def->src1); |
| } |
| |
| static int simplify_mul_div(struct instruction *insn, long long value) |
| { |
| unsigned long long sbit = 1ULL << (insn->size - 1); |
| unsigned long long bits = sbit | (sbit - 1); |
| |
| if (value == 1) |
| return replace_with_pseudo(insn, insn->src1); |
| |
| switch (insn->opcode) { |
| case OP_MUL: |
| if (value == 0) |
| return replace_with_pseudo(insn, insn->src2); |
| /* Fall through */ |
| case OP_DIVS: |
| if (!(value & sbit)) // positive |
| break; |
| |
| value |= ~bits; |
| if (value == -1) { |
| insn->opcode = OP_NEG; |
| return REPEAT_CSE; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int simplify_seteq_setne(struct instruction *insn, long long value) |
| { |
| pseudo_t old = insn->src1; |
| struct instruction *def; |
| unsigned osize; |
| int inverse; |
| int opcode; |
| |
| if (value != 0 && value != 1) |
| return 0; |
| |
| if (old->type != PSEUDO_REG) |
| return 0; |
| def = old->def; |
| if (!def) |
| return 0; |
| |
| inverse = (insn->opcode == OP_SET_NE) == value; |
| if (!inverse && def->size == 1 && insn->size == 1) { |
| // Replace: |
| // setne %r <- %s, $0 |
| // or: |
| // seteq %r <- %s, $1 |
| // by %s when boolean |
| return replace_with_pseudo(insn, old); |
| } |
| opcode = def->opcode; |
| switch (opcode) { |
| case OP_AND: |
| if (inverse) |
| break; |
| if (def->size != insn->size) |
| break; |
| if (def->src2->type != PSEUDO_VAL) |
| break; |
| if (def->src2->value != 1) |
| break; |
| return replace_with_pseudo(insn, old); |
| case OP_FPCMP ... OP_BINCMP_END: |
| // Convert: |
| // setcc.n %t <- %a, %b |
| // setne.m %r <- %t, $0 |
| // into: |
| // setcc.n %t <- %a, %b |
| // setcc.m %r <- %a, $b |
| // and similar for setne/eq ... 0/1 |
| insn->opcode = inverse ? opcode_table[opcode].negate : opcode; |
| use_pseudo(insn, def->src1, &insn->src1); |
| use_pseudo(insn, def->src2, &insn->src2); |
| remove_usage(old, &insn->src1); |
| return REPEAT_CSE; |
| |
| case OP_SEXT: |
| if (value && (def->orig_type->bit_size == 1)) |
| break; |
| /* Fall through */ |
| case OP_ZEXT: |
| // Convert: |
| // *ext.m %s <- (1) %a |
| // setne.1 %r <- %s, $0 |
| // into: |
| // setne.1 %s <- %a, $0 |
| // and same for setne/eq ... 0/1 |
| return replace_pseudo(insn, &insn->src1, def->src); |
| case OP_TRUNC: |
| if (multi_users(old)) |
| break; |
| // convert |
| // trunc.n %s <- (o) %a |
| // setne.m %r <- %s, $0 |
| // into: |
| // and.o %s <- %a, $((1 << o) - 1) |
| // setne.m %r <- %s, $0 |
| // and same for setne/eq ... 0/1 |
| osize = def->size; |
| def->opcode = OP_AND; |
| def->type = def->orig_type; |
| def->size = def->type->bit_size; |
| def->src2 = value_pseudo(bits_mask(osize)); |
| return REPEAT_CSE; |
| } |
| return 0; |
| } |
| |
| static int simplify_constant_mask(struct instruction *insn, unsigned long long mask) |
| { |
| pseudo_t old = insn->src1; |
| unsigned long long omask; |
| unsigned long long nmask; |
| struct instruction *def; |
| int osize; |
| |
| switch (DEF_OPCODE(def, old)) { |
| case OP_FPCMP ... OP_BINCMP_END: |
| osize = 1; |
| goto oldsize; |
| case OP_OR: |
| return simplify_mask_or(insn, mask, def); |
| case OP_LSR: |
| case OP_SHL: |
| return simplify_mask_shift(def, mask); |
| case OP_ZEXT: |
| osize = def->orig_type->bit_size; |
| /* fall through */ |
| oldsize: |
| omask = (1ULL << osize) - 1; |
| nmask = mask & omask; |
| if (nmask == omask) |
| // the AND mask is redundant |
| return replace_with_pseudo(insn, old); |
| if (nmask != mask) { |
| // can use a smaller mask |
| insn->src2 = value_pseudo(nmask); |
| return REPEAT_CSE; |
| } |
| break; |
| } |
| return 0; |
| } |
| |
| static int simplify_constant_rightside(struct instruction *insn) |
| { |
| long long value = insn->src2->value; |
| long long sbit = 1ULL << (insn->size - 1); |
| long long bits = sbit | (sbit - 1); |
| |
| switch (insn->opcode) { |
| case OP_OR: |
| if ((value & bits) == bits) |
| return replace_with_pseudo(insn, insn->src2); |
| goto case_neutral_zero; |
| |
| case OP_XOR: |
| if ((value & bits) == bits) { |
| insn->opcode = OP_NOT; |
| return REPEAT_CSE; |
| } |
| goto case_neutral_zero; |
| |
| case OP_SUB: |
| if (value) { |
| insn->opcode = OP_ADD; |
| insn->src2 = value_pseudo(-value); |
| return REPEAT_CSE; |
| } |
| /* Fall through */ |
| case OP_ADD: |
| case_neutral_zero: |
| if (!value) |
| return replace_with_pseudo(insn, insn->src1); |
| return 0; |
| case OP_ASR: |
| case OP_SHL: |
| case OP_LSR: |
| return simplify_shift(insn, insn->src1, value); |
| |
| case OP_MODU: case OP_MODS: |
| if (value == 1) |
| return replace_with_pseudo(insn, value_pseudo(0)); |
| return 0; |
| |
| case OP_DIVU: case OP_DIVS: |
| case OP_MUL: |
| return simplify_mul_div(insn, value); |
| |
| case OP_AND: |
| if (!value) |
| return replace_with_pseudo(insn, insn->src2); |
| if ((value & bits) == bits) |
| return replace_with_pseudo(insn, insn->src1); |
| return simplify_constant_mask(insn, value); |
| |
| case OP_SET_NE: |
| case OP_SET_EQ: |
| return simplify_seteq_setne(insn, value); |
| } |
| return 0; |
| } |
| |
| static int simplify_constant_leftside(struct instruction *insn) |
| { |
| long long value = insn->src1->value; |
| |
| switch (insn->opcode) { |
| case OP_ADD: case OP_OR: case OP_XOR: |
| if (!value) |
| return replace_with_pseudo(insn, insn->src2); |
| return 0; |
| |
| case OP_SHL: |
| case OP_LSR: case OP_ASR: |
| case OP_AND: |
| case OP_MUL: |
| if (!value) |
| return replace_with_pseudo(insn, insn->src1); |
| return 0; |
| } |
| return 0; |
| } |
| |
| static int simplify_constant_binop(struct instruction *insn) |
| { |
| pseudo_t res = eval_insn(insn); |
| |
| if (!res) |
| return 0; |
| |
| replace_with_pseudo(insn, res); |
| return REPEAT_CSE; |
| } |
| |
| static int simplify_binop_same_args(struct instruction *insn, pseudo_t arg) |
| { |
| switch (insn->opcode) { |
| case OP_SET_NE: |
| case OP_SET_LT: case OP_SET_GT: |
| case OP_SET_B: case OP_SET_A: |
| if (Wtautological_compare) |
| warning(insn->pos, "self-comparison always evaluates to false"); |
| case OP_SUB: |
| case OP_XOR: |
| return replace_with_pseudo(insn, value_pseudo(0)); |
| |
| case OP_SET_EQ: |
| case OP_SET_LE: case OP_SET_GE: |
| case OP_SET_BE: case OP_SET_AE: |
| if (Wtautological_compare) |
| warning(insn->pos, "self-comparison always evaluates to true"); |
| return replace_with_pseudo(insn, value_pseudo(1)); |
| |
| case OP_AND: |
| case OP_OR: |
| return replace_with_pseudo(insn, arg); |
| |
| default: |
| break; |
| } |
| |
| return 0; |
| } |
| |
| static int simplify_binop(struct instruction *insn) |
| { |
| if (dead_insn(insn, &insn->src1, &insn->src2, NULL)) |
| return REPEAT_CSE; |
| if (constant(insn->src1)) { |
| if (constant(insn->src2)) |
| return simplify_constant_binop(insn); |
| return simplify_constant_leftside(insn); |
| } |
| if (constant(insn->src2)) |
| return simplify_constant_rightside(insn); |
| if (insn->src1 == insn->src2) |
| return simplify_binop_same_args(insn, insn->src1); |
| return 0; |
| } |
| |
| static void switch_pseudo(struct instruction *insn1, pseudo_t *pp1, struct instruction *insn2, pseudo_t *pp2) |
| { |
| pseudo_t p1 = *pp1, p2 = *pp2; |
| |
| use_pseudo(insn1, p2, pp1); |
| use_pseudo(insn2, p1, pp2); |
| remove_usage(p1, pp1); |
| remove_usage(p2, pp2); |
| } |
| |
| static int canonical_order(pseudo_t p1, pseudo_t p2) |
| { |
| /* symbol/constants on the right */ |
| if (p1->type == PSEUDO_VAL) |
| return p2->type == PSEUDO_VAL; |
| |
| if (p1->type == PSEUDO_SYM) |
| return p2->type == PSEUDO_SYM || p2->type == PSEUDO_VAL; |
| |
| return 1; |
| } |
| |
| static int canonicalize_commutative(struct instruction *insn) |
| { |
| if (canonical_order(insn->src1, insn->src2)) |
| return 0; |
| |
| switch_pseudo(insn, &insn->src1, insn, &insn->src2); |
| return repeat_phase |= REPEAT_CSE; |
| } |
| |
| static int canonicalize_compare(struct instruction *insn) |
| { |
| if (canonical_order(insn->src1, insn->src2)) |
| return 0; |
| |
| switch_pseudo(insn, &insn->src1, insn, &insn->src2); |
| insn->opcode = opcode_table[insn->opcode].swap; |
| return repeat_phase |= REPEAT_CSE; |
| } |
| |
| static inline int simple_pseudo(pseudo_t pseudo) |
| { |
| return pseudo->type == PSEUDO_VAL || pseudo->type == PSEUDO_SYM; |
| } |
| |
| static int simplify_associative_binop(struct instruction *insn) |
| { |
| struct instruction *def; |
| pseudo_t pseudo = insn->src1; |
| |
| if (!simple_pseudo(insn->src2)) |
| return 0; |
| if (pseudo->type != PSEUDO_REG) |
| return 0; |
| def = pseudo->def; |
| if (def == insn) |
| return 0; |
| if (def->opcode != insn->opcode) |
| return 0; |
| if (!simple_pseudo(def->src2)) |
| return 0; |
| if (multi_users(def->target)) |
| return 0; |
| switch_pseudo(def, &def->src1, insn, &insn->src2); |
| return REPEAT_CSE; |
| } |
| |
| static int simplify_constant_unop(struct instruction *insn) |
| { |
| long long val = insn->src1->value; |
| long long res, mask; |
| |
| switch (insn->opcode) { |
| case OP_NOT: |
| res = ~val; |
| break; |
| case OP_NEG: |
| res = -val; |
| break; |
| case OP_SEXT: |
| mask = 1ULL << (insn->orig_type->bit_size-1); |
| if (val & mask) |
| val |= ~(mask | (mask-1)); |
| /* fall through */ |
| case OP_ZEXT: |
| case OP_TRUNC: |
| res = val; |
| break; |
| default: |
| return 0; |
| } |
| mask = 1ULL << (insn->size-1); |
| res &= mask | (mask-1); |
| |
| replace_with_pseudo(insn, value_pseudo(res)); |
| return REPEAT_CSE; |
| } |
| |
| static int simplify_unop(struct instruction *insn) |
| { |
| if (dead_insn(insn, &insn->src1, NULL, NULL)) |
| return REPEAT_CSE; |
| if (constant(insn->src1)) |
| return simplify_constant_unop(insn); |
| |
| switch (insn->opcode) { |
| struct instruction *def; |
| |
| case OP_NOT: |
| def = insn->src->def; |
| if (def && def->opcode == OP_NOT) |
| return replace_with_pseudo(insn, def->src); |
| break; |
| case OP_NEG: |
| def = insn->src->def; |
| if (def && def->opcode == OP_NEG) |
| return replace_with_pseudo(insn, def->src); |
| break; |
| default: |
| return 0; |
| } |
| return 0; |
| } |
| |
| static int simplify_one_memop(struct instruction *insn, pseudo_t orig) |
| { |
| pseudo_t addr = insn->src; |
| pseudo_t new, off; |
| |
| if (addr->type == PSEUDO_REG) { |
| struct instruction *def = addr->def; |
| if (def->opcode == OP_SYMADDR && def->src) { |
| kill_use(&insn->src); |
| use_pseudo(insn, def->src, &insn->src); |
| return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP; |
| } |
| if (def->opcode == OP_ADD) { |
| new = def->src1; |
| off = def->src2; |
| if (constant(off)) |
| goto offset; |
| new = off; |
| off = def->src1; |
| if (constant(off)) |
| goto offset; |
| return 0; |
| } |
| } |
| return 0; |
| |
| offset: |
| /* Invalid code */ |
| if (new == orig || new == addr) { |
| if (new == VOID) |
| return 0; |
| /* |
| * If some BB have been removed it is possible that this |
| * memop is in fact part of a dead BB. In this case |
| * we must not warn since nothing is wrong. |
| * If not part of a dead BB this will be redone after |
| * the BBs have been cleaned up. |
| */ |
| if (repeat_phase & REPEAT_CFG_CLEANUP) |
| return 0; |
| warning(insn->pos, "crazy programmer"); |
| replace_pseudo(insn, &insn->src, VOID); |
| return 0; |
| } |
| insn->offset += off->value; |
| replace_pseudo(insn, &insn->src, new); |
| return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP; |
| } |
| |
| /// |
| // simplify memops instructions |
| // |
| // :note: We walk the whole chain of adds/subs backwards. |
| // That's not only more efficient, but it allows us to find loops. |
| static int simplify_memop(struct instruction *insn) |
| { |
| int one, ret = 0; |
| pseudo_t orig = insn->src; |
| |
| do { |
| one = simplify_one_memop(insn, orig); |
| ret |= one; |
| } while (one); |
| return ret; |
| } |
| |
| static int simplify_cast(struct instruction *insn) |
| { |
| unsigned long long mask; |
| struct instruction *def; |
| pseudo_t src; |
| pseudo_t val; |
| int osize; |
| int size; |
| |
| if (dead_insn(insn, &insn->src, NULL, NULL)) |
| return REPEAT_CSE; |
| |
| src = insn->src; |
| |
| /* A cast of a constant? */ |
| if (constant(src)) |
| return simplify_constant_unop(insn); |
| |
| // can merge with the previous instruction? |
| size = insn->size; |
| def = src->def; |
| switch (def_opcode(src)) { |
| case OP_AND: |
| val = def->src2; |
| if (val->type != PSEUDO_VAL) |
| break; |
| /* A cast of a AND might be a no-op.. */ |
| switch (insn->opcode) { |
| case OP_TRUNC: |
| if (multi_users(src)) |
| break; |
| def->opcode = OP_TRUNC; |
| def->orig_type = def->type; |
| def->type = insn->type; |
| def->size = size; |
| |
| insn->opcode = OP_AND; |
| mask = val->value; |
| mask &= (1ULL << size) - 1; |
| insn->src2 = value_pseudo(mask); |
| return REPEAT_CSE; |
| |
| case OP_SEXT: |
| if (val->value & (1 << (def->size - 1))) |
| break; |
| // OK, sign bit is 0 |
| case OP_ZEXT: |
| if (multi_users(src)) |
| break; |
| // transform: |
| // and.n %b <- %a, M |
| // *ext.m %c <- (n) %b |
| // into: |
| // zext.m %b <- %a |
| // and.m %c <- %b, M |
| // For ZEXT, the mask will always be small |
| // enough. For SEXT, it can only be done if |
| // the mask force the sign bit to 0. |
| def->opcode = OP_ZEXT; |
| def->orig_type = insn->orig_type; |
| def->type = insn->type; |
| def->size = insn->size; |
| insn->opcode = OP_AND; |
| insn->src2 = val; |
| return REPEAT_CSE; |
| } |
| break; |
| case OP_FPCMP ... OP_BINCMP_END: |
| switch (insn->opcode) { |
| case OP_SEXT: |
| if (insn->size == 1) |
| break; |
| /* fall through */ |
| case OP_ZEXT: |
| case OP_TRUNC: |
| // simplify: |
| // setcc.n %t <- %a, %b |
| // zext.m %r <- (n) %t |
| // into: |
| // setcc.m %r <- %a, %b |
| // and same for s/zext/trunc/ |
| insn->opcode = def->opcode; |
| use_pseudo(insn, def->src2, &insn->src2); |
| return replace_pseudo(insn, &insn->src1, def->src1); |
| } |
| break; |
| case OP_OR: |
| switch (insn->opcode) { |
| case OP_TRUNC: |
| mask = bits_mask(insn->size); |
| return simplify_mask_or(insn, mask, def); |
| } |
| break; |
| case OP_LSR: |
| case OP_SHL: |
| if (insn->opcode != OP_TRUNC) |
| break; |
| mask = bits_mask(insn->size); |
| return simplify_mask_shift(def, mask); |
| case OP_TRUNC: |
| switch (insn->opcode) { |
| case OP_TRUNC: |
| insn->orig_type = def->orig_type; |
| return replace_pseudo(insn, &insn->src1, def->src); |
| case OP_ZEXT: |
| if (size != def->orig_type->bit_size) |
| break; |
| insn->opcode = OP_AND; |
| insn->src2 = value_pseudo((1ULL << def->size) - 1); |
| return replace_pseudo(insn, &insn->src1, def->src); |
| } |
| break; |
| case OP_ZEXT: |
| switch (insn->opcode) { |
| case OP_SEXT: |
| insn->opcode = OP_ZEXT; |
| /* fall through */ |
| case OP_ZEXT: |
| insn->orig_type = def->orig_type; |
| return replace_pseudo(insn, &insn->src, def->src); |
| } |
| /* fall through */ |
| case OP_SEXT: |
| switch (insn->opcode) { |
| case OP_TRUNC: |
| osize = def->orig_type->bit_size; |
| if (size == osize) |
| return replace_with_pseudo(insn, def->src); |
| if (size > osize) |
| insn->opcode = def->opcode; |
| insn->orig_type = def->orig_type; |
| return replace_pseudo(insn, &insn->src, def->src); |
| } |
| switch (insn->opcode) { |
| case OP_SEXT: |
| insn->orig_type = def->orig_type; |
| return replace_pseudo(insn, &insn->src, def->src); |
| } |
| break; |
| } |
| |
| return 0; |
| } |
| |
| static int simplify_select(struct instruction *insn) |
| { |
| pseudo_t cond, src1, src2; |
| |
| if (dead_insn(insn, &insn->src1, &insn->src2, &insn->src3)) |
| return REPEAT_CSE; |
| |
| cond = insn->src1; |
| src1 = insn->src2; |
| src2 = insn->src3; |
| if (constant(cond) || src1 == src2) { |
| pseudo_t *kill, take; |
| kill_use(&insn->src1); |
| take = cond->value ? src1 : src2; |
| kill = cond->value ? &insn->src3 : &insn->src2; |
| kill_use(kill); |
| replace_with_pseudo(insn, take); |
| return REPEAT_CSE; |
| } |
| if (constant(src1) && constant(src2)) { |
| long long val1 = src1->value; |
| long long val2 = src2->value; |
| |
| /* The pair 0/1 is special - replace with SETNE/SETEQ */ |
| if ((val1 | val2) == 1) { |
| int opcode = OP_SET_EQ; |
| if (val1) { |
| src1 = src2; |
| opcode = OP_SET_NE; |
| } |
| insn->opcode = opcode; |
| /* insn->src1 is already cond */ |
| insn->src2 = src1; /* Zero */ |
| return REPEAT_CSE; |
| } |
| } |
| if (cond == src2 && is_zero(src1)) { |
| kill_use(&insn->src1); |
| kill_use(&insn->src3); |
| replace_with_pseudo(insn, value_pseudo(0)); |
| return REPEAT_CSE; |
| } |
| return 0; |
| } |
| |
| static int is_in_range(pseudo_t src, long long low, long long high) |
| { |
| long long value; |
| |
| switch (src->type) { |
| case PSEUDO_VAL: |
| value = src->value; |
| return value >= low && value <= high; |
| default: |
| return 0; |
| } |
| } |
| |
| static int simplify_range(struct instruction *insn) |
| { |
| pseudo_t src1, src2, src3; |
| |
| src1 = insn->src1; |
| src2 = insn->src2; |
| src3 = insn->src3; |
| if (src2->type != PSEUDO_VAL || src3->type != PSEUDO_VAL) |
| return 0; |
| if (is_in_range(src1, src2->value, src3->value)) { |
| kill_instruction(insn); |
| return REPEAT_CSE; |
| } |
| return 0; |
| } |
| |
| /// |
| // simplify SET_NE/EQ $0 + BR |
| static int simplify_cond_branch(struct instruction *br, struct instruction *def, pseudo_t newcond) |
| { |
| replace_pseudo(br, &br->cond, newcond); |
| if (def->opcode == OP_SET_EQ) { |
| struct basic_block *tmp = br->bb_true; |
| br->bb_true = br->bb_false; |
| br->bb_false = tmp; |
| } |
| return REPEAT_CSE; |
| } |
| |
| static int simplify_branch(struct instruction *insn) |
| { |
| pseudo_t cond = insn->cond; |
| |
| /* Constant conditional */ |
| if (constant(cond)) { |
| insert_branch(insn->bb, insn, cond->value ? insn->bb_true : insn->bb_false); |
| return REPEAT_CSE; |
| } |
| |
| /* Same target? */ |
| if (insn->bb_true == insn->bb_false) { |
| struct basic_block *bb = insn->bb; |
| struct basic_block *target = insn->bb_false; |
| remove_bb_from_list(&target->parents, bb, 1); |
| remove_bb_from_list(&bb->children, target, 1); |
| insn->bb_false = NULL; |
| kill_use(&insn->cond); |
| insn->cond = NULL; |
| insn->opcode = OP_BR; |
| return REPEAT_CSE; |
| } |
| |
| /* Conditional on a SETNE $0 or SETEQ $0 */ |
| if (cond->type == PSEUDO_REG) { |
| struct instruction *def = cond->def; |
| |
| if (def->opcode == OP_SET_NE || def->opcode == OP_SET_EQ) { |
| if (constant(def->src1) && !def->src1->value) |
| return simplify_cond_branch(insn, def, def->src2); |
| if (constant(def->src2) && !def->src2->value) |
| return simplify_cond_branch(insn, def, def->src1); |
| } |
| if (def->opcode == OP_SEL) { |
| if (constant(def->src2) && constant(def->src3)) { |
| long long val1 = def->src2->value; |
| long long val2 = def->src3->value; |
| if (!val1 && !val2) { |
| insert_branch(insn->bb, insn, insn->bb_false); |
| return REPEAT_CSE; |
| } |
| if (val1 && val2) { |
| insert_branch(insn->bb, insn, insn->bb_true); |
| return REPEAT_CSE; |
| } |
| if (val2) { |
| struct basic_block *tmp = insn->bb_true; |
| insn->bb_true = insn->bb_false; |
| insn->bb_false = tmp; |
| } |
| return replace_pseudo(insn, &insn->cond, def->src1); |
| } |
| } |
| if (def->opcode == OP_SEXT || def->opcode == OP_ZEXT) |
| return replace_pseudo(insn, &insn->cond, def->src); |
| } |
| return 0; |
| } |
| |
| static int simplify_switch(struct instruction *insn) |
| { |
| pseudo_t cond = insn->cond; |
| long long val; |
| struct multijmp *jmp; |
| |
| if (!constant(cond)) |
| return 0; |
| val = insn->cond->value; |
| |
| FOR_EACH_PTR(insn->multijmp_list, jmp) { |
| /* Default case */ |
| if (jmp->begin > jmp->end) |
| goto found; |
| if (val >= jmp->begin && val <= jmp->end) |
| goto found; |
| } END_FOR_EACH_PTR(jmp); |
| warning(insn->pos, "Impossible case statement"); |
| return 0; |
| |
| found: |
| insert_branch(insn->bb, insn, jmp->target); |
| return REPEAT_CSE; |
| } |
| |
| int simplify_instruction(struct instruction *insn) |
| { |
| if (!insn->bb) |
| return 0; |
| switch (insn->opcode) { |
| case OP_ADD: case OP_MUL: |
| case OP_AND: case OP_OR: case OP_XOR: |
| canonicalize_commutative(insn); |
| if (simplify_binop(insn)) |
| return REPEAT_CSE; |
| return simplify_associative_binop(insn); |
| |
| case OP_SET_EQ: case OP_SET_NE: |
| canonicalize_commutative(insn); |
| return simplify_binop(insn); |
| |
| case OP_SET_LE: case OP_SET_GE: |
| case OP_SET_LT: case OP_SET_GT: |
| case OP_SET_B: case OP_SET_A: |
| case OP_SET_BE: case OP_SET_AE: |
| canonicalize_compare(insn); |
| /* fall through */ |
| case OP_SUB: |
| case OP_DIVU: case OP_DIVS: |
| case OP_MODU: case OP_MODS: |
| case OP_SHL: |
| case OP_LSR: case OP_ASR: |
| return simplify_binop(insn); |
| |
| case OP_NOT: case OP_NEG: case OP_FNEG: |
| return simplify_unop(insn); |
| case OP_LOAD: |
| if (!has_users(insn->target)) |
| return kill_instruction(insn); |
| /* fall-through */ |
| case OP_STORE: |
| return simplify_memop(insn); |
| case OP_SYMADDR: |
| if (dead_insn(insn, &insn->src, NULL, NULL)) |
| return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP; |
| return replace_with_pseudo(insn, insn->src); |
| case OP_SEXT: case OP_ZEXT: |
| case OP_TRUNC: |
| return simplify_cast(insn); |
| case OP_FCVTU: case OP_FCVTS: |
| case OP_UCVTF: case OP_SCVTF: |
| case OP_FCVTF: |
| case OP_PTRCAST: |
| if (dead_insn(insn, &insn->src, NULL, NULL)) |
| return REPEAT_CSE; |
| break; |
| case OP_UTPTR: |
| case OP_PTRTU: |
| return replace_with_pseudo(insn, insn->src); |
| case OP_SLICE: |
| if (dead_insn(insn, &insn->src, NULL, NULL)) |
| return REPEAT_CSE; |
| break; |
| case OP_SETVAL: |
| case OP_SETFVAL: |
| if (dead_insn(insn, NULL, NULL, NULL)) |
| return REPEAT_CSE; |
| break; |
| case OP_PHI: |
| if (dead_insn(insn, NULL, NULL, NULL)) { |
| kill_use_list(insn->phi_list); |
| return REPEAT_CSE; |
| } |
| return clean_up_phi(insn); |
| case OP_PHISOURCE: |
| if (dead_insn(insn, &insn->phi_src, NULL, NULL)) |
| return REPEAT_CSE; |
| break; |
| case OP_SEL: |
| return simplify_select(insn); |
| case OP_CBR: |
| return simplify_branch(insn); |
| case OP_SWITCH: |
| return simplify_switch(insn); |
| case OP_RANGE: |
| return simplify_range(insn); |
| case OP_FADD: |
| case OP_FSUB: |
| case OP_FMUL: |
| case OP_FDIV: |
| if (dead_insn(insn, &insn->src1, &insn->src2, NULL)) |
| return REPEAT_CSE; |
| break; |
| } |
| return 0; |
| } |