diff options
Diffstat (limited to 'simplify.c')
| -rw-r--r-- | simplify.c | 73 |
1 files changed, 65 insertions, 8 deletions
@@ -454,6 +454,13 @@ static inline pseudo_t is_same_op(pseudo_t src, int op, unsigned osize) return def->src; } +static bool is_negate_of(pseudo_t p, pseudo_t ref) +{ + struct instruction *def; + + return (DEF_OPCODE(def, p) == OP_NEG) && (def->src == ref); +} + /// // replace the operand of an instruction // @insn: the instruction @@ -1162,13 +1169,49 @@ static int simplify_seteq_setne(struct instruction *insn, long long value) static int simplify_compare_constant(struct instruction *insn, long long value) { - unsigned long long bits = bits_mask(insn->itype->bit_size); + unsigned size = insn->itype->bit_size; + unsigned long long bits = bits_mask(size); struct instruction *def; pseudo_t src1, src2; unsigned int osize; int changed = 0; switch (insn->opcode) { + case OP_SET_LT: + if (value == sign_bit(size)) // (x < SMIN) --> 0 + return replace_with_pseudo(insn, value_pseudo(0)); + if (value == sign_mask(size)) // (x < SMAX) --> (x != SMAX) + return replace_opcode(insn, OP_SET_NE); + if (value == sign_bit(size) + 1)// (x < SMIN + 1) --> (x == SMIN) + return replace_binop_value(insn, OP_SET_EQ, sign_bit(size)); + changed |= replace_binop_value(insn, OP_SET_LE, (value - 1) & bits); + break; + case OP_SET_LE: + if (value == sign_mask(size)) // (x <= SMAX) --> 1 + return replace_with_pseudo(insn, value_pseudo(1)); + if (value == sign_bit(size)) // (x <= SMIN) --> (x == SMIN) + return replace_opcode(insn, OP_SET_EQ); + if (value == sign_mask(size) - 1) // (x <= SMAX - 1) --> (x != SMAX) + return replace_binop_value(insn, OP_SET_NE, sign_mask(size)); + break; + case OP_SET_GE: + if (value == sign_bit(size)) // (x >= SMIN) --> 1 + return replace_with_pseudo(insn, value_pseudo(1)); + if (value == sign_mask(size)) // (x >= SMAX) --> (x == SMAX) + return replace_opcode(insn, OP_SET_EQ); + if (value == sign_bit(size) + 1)// (x >= SMIN + 1) --> (x != SMIN) + return replace_binop_value(insn, OP_SET_NE, sign_bit(size)); + changed |= replace_binop_value(insn, OP_SET_GT, (value - 1) & bits); + break; + case OP_SET_GT: + if (value == sign_mask(size)) // (x > SMAX) --> 0 + return replace_with_pseudo(insn, value_pseudo(0)); + if (value == sign_bit(size)) // (x > SMIN) --> (x != SMIN) + return replace_opcode(insn, OP_SET_NE); + if (value == sign_mask(size) - 1) // (x > SMAX - 1) --> (x == SMAX) + return replace_binop_value(insn, OP_SET_EQ, sign_mask(size)); + break; + case OP_SET_B: if (!value) // (x < 0) --> 0 return replace_with_pseudo(insn, value_pseudo(0)); @@ -1177,7 +1220,7 @@ static int simplify_compare_constant(struct instruction *insn, long long value) else if (value == bits) // (x < ~0) --> (x != ~0) return replace_binop_value(insn, OP_SET_NE, value); else // (x < y) --> (x <= (y-1)) - changed |= replace_binop_value(insn, OP_SET_BE, value - 1); + changed |= replace_binop_value(insn, OP_SET_BE, (value - 1) & bits); break; case OP_SET_AE: if (!value) // (x >= 0) --> 1 @@ -1187,7 +1230,7 @@ static int simplify_compare_constant(struct instruction *insn, long long value) else if (value == bits) // (x >= ~0) --> (x == ~0) return replace_binop_value(insn, OP_SET_EQ, value); else // (x >= y) --> (x > (y-1) - changed |= replace_binop_value(insn, OP_SET_A, value - 1); + changed |= replace_binop_value(insn, OP_SET_A, (value - 1) & bits); break; case OP_SET_BE: if (!value) // (x <= 0) --> (x == 0) @@ -1217,7 +1260,7 @@ static int simplify_compare_constant(struct instruction *insn, long long value) switch (DEF_OPCODE(def, src1)) { case OP_SEXT: // sext(x) cmp C --> x cmp trunc(C) osize = def->orig_type->bit_size; - if (is_signed_constant(value, osize, def->size)) { + if (is_signed_constant(value, osize, size)) { insn->itype = def->orig_type; insn->src2 = value_pseudo(zero_extend(value, osize)); return replace_pseudo(insn, &insn->src1, def->src); @@ -1238,13 +1281,13 @@ static int simplify_compare_constant(struct instruction *insn, long long value) } break; case OP_SET_LT: case OP_SET_LE: - if (value >= sign_bit(osize)) + if (value < sign_bit(size)) return replace_with_value(insn, 1); else return replace_with_value(insn, 0); break; case OP_SET_GE: case OP_SET_GT: - if (value >= sign_bit(osize)) + if (value < sign_bit(size)) return replace_with_value(insn, 0); else return replace_with_value(insn, 1); @@ -1263,13 +1306,13 @@ static int simplify_compare_constant(struct instruction *insn, long long value) } switch (insn->opcode) { case OP_SET_LT: case OP_SET_LE: - if (sign_extend(value, def->size) > (long long)bits) + if (sign_extend(value, size) > (long long)bits) return replace_with_value(insn, 1); else return replace_with_value(insn, 0); break; case OP_SET_GE: case OP_SET_GT: - if (sign_extend(value, def->size) > (long long)bits) + if (sign_extend(value, size) > (long long)bits) return replace_with_value(insn, 0); else return replace_with_value(insn, 1); @@ -2265,6 +2308,20 @@ static int simplify_select(struct instruction *insn) if (src2 == def->src1 && src1 == def->src2) return replace_with_pseudo(insn, src1); // SEL(y!=x,x,y) --> x break; + case OP_SET_LE: case OP_SET_LT: + case OP_SET_BE: case OP_SET_B: + if (!one_use(cond)) + break; + // SEL(x {<,<=} y, a, b) --> SEL(x {>=,>} y, b, a) + def->opcode = opcode_negate(def->opcode); + return switch_pseudo(insn, &insn->src2, insn, &insn->src3); + case OP_SET_GT: + if (one_use(cond) && is_zero(def->src2)) { + if (is_negate_of(src2, src1)) + // SEL(x > 0, a, -a) --> SEL(x >= 0, a, -a) + return replace_opcode(def, OP_SET_GE); + } + break; case OP_SEL: if (constant(def->src2) && constant(def->src3)) { // Is the def of the conditional another select? |