diff options
Diffstat (limited to 'simplify.c')
| -rw-r--r-- | simplify.c | 47 |
1 files changed, 46 insertions, 1 deletions
@@ -570,7 +570,10 @@ static long long check_shift_count(struct instruction *insn, unsigned long long static int simplify_shift(struct instruction *insn, pseudo_t pseudo, long long value) { + struct instruction *def; + unsigned long long nval; unsigned int size; + pseudo_t src2; if (!value) return replace_with_pseudo(insn, pseudo); @@ -583,15 +586,57 @@ static int simplify_shift(struct instruction *insn, pseudo_t pseudo, long long v case OP_ASR: if (value >= size) return 0; + if (pseudo->type != PSEUDO_REG) + break; + def = pseudo->def; + switch (def->opcode) { + 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) + break; + value += nval; + if (value >= size) + value = size - 1; + goto new_value; + } break; case OP_LSR: size = operand_size(insn, pseudo); /* fall through */ case OP_SHL: if (value >= size) - return replace_with_pseudo(insn, value_pseudo(0)); + goto zero; + if (pseudo->type != PSEUDO_REG) + break; + def = pseudo->def; + if (def->opcode == insn->opcode) { + 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)); } static int simplify_mul_div(struct instruction *insn, long long value) |