In preparation of the missing simplification of ((x >> S) << S), reorganize the existing simplification of ((x << S) >> S). Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> --- simplify.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/simplify.c b/simplify.c index 0720070a8..b1ccc510d 100644 --- a/simplify.c +++ b/simplify.c @@ -671,14 +671,12 @@ static int simplify_shift(struct instruction *insn, pseudo_t pseudo, long long v return simplify_or_lsr(insn, src, def->src1, value); break; case OP_SHL: - // replace (A << S) >> S - // by A & (Mask(size) >> S) + // replace ((x << S) >> S) + // by (x & (-1 >> S)) if (def->src2 != insn->src2) break; - size = insn->size - value; - insn->opcode = OP_AND; - insn->src2 = value_pseudo((1ULL << size) - 1); - return replace_pseudo(insn, &insn->src1, def->src1); + mask = bits_mask(insn->size - value); + goto replace_mask; } break; case OP_SHL: @@ -709,6 +707,10 @@ new_value: } 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) -- 2.18.0
