diff options
| -rw-r--r-- | pez.c | 121 |
1 files changed, 68 insertions, 53 deletions
@@ -2895,6 +2895,65 @@ commutate(enum op *op) static bool discard(Comp *cm); static bool +binexprimm(Comp *cm, enum op op, int8_t imm) +{ + enum op iop = 0; + if (op == Osub) { + // X - k turns into X + -k, but if k == -128 we cannot encode 128 + if (imm == -128) { + goto Bail; + } + imm = -imm; + goto Oadd; + } else if (op == Odiv && imm == 0) { + // the idiv fastpath assumes dividend is nonzero + goto Bail; + } else if (op == Omod && imm == 0) { + // the imod fastpath assumes dividend is nonzero + // always x % 0 = 0 + cm->has_k = 0; + TRY(discard(cm) && compop(cm, Ozero)); + return 1; + } else if (op == Omul) { + // try turn mul by powers of 2 into shifts + for (int exp = 0; exp < 8; ++exp) { + if (imm == 1 << exp) { + iop = Oishl; + imm = exp; + goto CompIop; + } + } + } + switch (op) { +Oadd: case Oadd: iop = Oiadd; break; + case Omul: iop = Oimul; break; + case Odiv: iop = Oidiv; break; + case Omod: iop = Oimod; break; + case Oband: iop = Oiband; break; + case Obior: iop = Oibior; break; + case Obxor: iop = Oibxor; break; + case Oshl: iop = Oishl; break; + case Oshra: iop = Oishra; break; + case Oshrl: iop = Oishrl; break; + case Olt: iop = Oilt; break; + case Ole: iop = Oile; break; + case Ogt: iop = Oigt; break; + case Oge: iop = Oige; break; + case Oeq: iop = Oieq; break; + case One: iop = Oine; break; + default: break; + } +CompIop: + assert(iop); + cm->has_k = 0; + TRY(compop(cm, iop) && compbyte(cm, imm)); + return 1; +Bail: + TRY(compop(cm, op)); + return 1; +} + +static bool binexpr(Comp *cm, char okind, bool (*prev)(Comp *)) { uint save = cm->code.len, save2, save3; @@ -2911,7 +2970,7 @@ binexpr(Comp *cm, char okind, bool (*prev)(Comp *)) Val lk = cm->k; bool has_lk = cm->has_k; int imm; - enum op opx = op, iop = 0; + enum op opx = op; TRY(flushconst(cm)); save2 = cm->code.len; @@ -2943,59 +3002,10 @@ binexpr(Comp *cm, char okind, bool (*prev)(Comp *)) } else if (cm->has_k && isimm(&imm, cm->k)) { // try immediate variants of ops TryImm: - if (opx == Osub) { - // X - k turns into X + -k, but if k == -128 we cannot encode 128 - if (imm == -128) { - goto Bail; - } - imm = -imm; - goto Oadd; - } else if (opx == Odiv && imm == 0) { - // the idiv fastpath assumes dividend is nonzero - goto Bail; - } else if (opx == Omod && imm == 0) { - // the imod fastpath assumes dividend is nonzero - // always x % 0 = 0 - cm->has_k = 0; - TRY(discard(cm) && compop(cm, Ozero)); - continue; - } else if (opx == Omul) { - // try turn mul by powers of 2 into shifts - for (int exp = 0; exp < 8; ++exp) { - if (imm == 1 << exp) { - iop = Oishl; - imm = exp; - goto CompIop; - } - } - } - switch (opx) { - Oadd: case Oadd: iop = Oiadd; break; - case Omul: iop = Oimul; break; - case Odiv: iop = Oidiv; break; - case Omod: iop = Oimod; break; - case Oband: iop = Oiband; break; - case Obior: iop = Oibior; break; - case Obxor: iop = Oibxor; break; - case Oshl: iop = Oishl; break; - case Oshra: iop = Oishra; break; - case Oshrl: iop = Oishrl; break; - case Olt: iop = Oilt; break; - case Ole: iop = Oile; break; - case Ogt: iop = Oigt; break; - case Oge: iop = Oige; break; - case Oeq: iop = Oieq; break; - case One: iop = Oine; break; - default: break; - } - CompIop: - assert(iop); - cm->has_k = 0; - TRY(compop(cm, iop) && compbyte(cm, (int8_t)imm)); + TRY(binexprimm(cm, opx, imm)); continue; } - Bail: - TRY(compop(cm, opx)); + TRY(compop(cm, op)); } while (okind != 'C' && (op2 = getbinop(&kind, &chr, cm)) == op); if (op2 != op && kind != 0) { stashbinop(cm, op2, kind, chr); @@ -3223,7 +3233,12 @@ setexpr(Comp *cm) TRY(condexpr(cm)); if (binop != Oset) { - TRY(compop(cm, binop)); + int imm; + if (cm->has_k && isimm(&imm, cm->k)) { + TRY(binexprimm(cm, binop, imm)); + } else { + TRY(compop(cm, binop)); + } } if (opcode == Oglobal) { |