#include "ir.h"
#include "u_endian.h"
#include <limits.h>

#ifdef __clang__
__attribute__((no_sanitize("float-cast-overflow"))) /* silence UBsan for float->int overflow */
#endif
static Ref
foldint(enum op op, enum irclass k, Ref lr, Ref rr)
{
   s64int x;
   union {
      s64int s;
      u64int u;
   } l = {.s = intconval(lr)}, r = {.s = intconval(rr)};
   bool w = cls2siz[k] == 8;
   if (in_range(op, Odiv, Ourem)) assert(r.u != 0);
   switch (op) {
   case Ocopy: x = l.s; break;
   case Oneg:  x = -l.s; break;
   case Onot:  x = ~l.s; break;
#define CVTF2I(TF, TI) do { \
   TF f = fltconval(lr);    \
   if (f != f) x = 0;       \
   else x = (TI)f;          \
} while (0)
   case Ocvtf32s: if (w) CVTF2I(float,  s64int); else CVTF2I(float,  int);  break;
   case Ocvtf32u: if (w) CVTF2I(float,  u64int); else CVTF2I(float,  uint); break;
   case Ocvtf64s: if (w) CVTF2I(double, s64int); else CVTF2I(double, int);  break;
   case Ocvtf64u: if (w) CVTF2I(double, u64int); else CVTF2I(double, uint); break;
#undef CVTF2I
   case Oexts8:  x = (schar)l.s; break;
   case Oextu8:  x = (uchar)l.s; break;
   case Oexts16: x = (short)l.s; break;
   case Oextu16: x = (ushort)l.s; break;
   case Oexts32: x = (int)l.s; break;
   case Oextu32: x = (uint)l.s; break;
   case Obswap16: x = bswap16(l.u); break;
   case Obswap32: x = bswap32(l.u); break;
   case Obswap64: x = bswap64(l.u); break;
   case Oadd:  x = l.u + r.u; break;
   case Osub:  x = l.u - r.u; break;
   case Omul:  x = l.u * r.u; break;
   case Odiv:  if (r.s == -1 && (w ? l.s == LLONG_MIN : (int)l.s == INT_MIN)) x = l.s;
               else x = w ? l.s / r.s : (int)l.s / (int)r.s;
               break;
   case Oudiv: x = w ? l.u / r.u : (uint)l.u / (uint)r.u; break;
   case Orem:  if (r.s == -1 && (w ? l.s == LLONG_MIN : (int)l.s == INT_MIN)) x = 0;
               else x = w ? l.s % r.s : (int)l.s % (int)r.s;
               break;
   case Ourem: x = w ? l.u % r.u : (uint)l.u % (uint)r.u; break;
   case Oand:  x = l.u & r.u; break;
   case Oior:  x = l.u | r.u; break;
   case Oxor:  x = l.u ^ r.u; break;
   case Oshl:  x = l.u << (r.u & (w ? 63 : 31)); break;
   case Oslr:  x = w ? l.u >> (r.u&63) : (int)l.s >> (r.u&31); break;
   case Osar:  x = w ? l.s >> (r.u&63) : (int)l.s >> (r.u&31); break;
   case Oequ:  x = l.s == r.s; break;
   case Oneq:  x = l.s != r.s; break;
   case Olth:  x = l.s < r.s; break;
   case Ogth:  x = l.s > r.s; break;
   case Olte:  x = l.s <= r.s; break;
   case Ogte:  x = l.s >= r.s; break;
   case Oulth: x = l.u < r.u; break;
   case Ougth: x = l.u > r.u; break;
   case Oulte: x = l.u <= r.u; break;
   case Ougte: x = l.u >= r.u; break;
   default: assert(0);
   }
   if (!w) x = (int)x;
   return mkintcon(k, x);
}

static Ref
foldflt(enum op op, enum irclass k, Ref lr, Ref rr)
{
   int xi;
   double x, l = fltconval(lr), r = fltconval(rr);
   bool w = k == KF64;
   switch (op) {
   case Ocopy: x = l; break;
   case Oneg:  x = -l; break;
   case Ocvtf32f64: x = (float)l; break;
   case Ocvtf64f32: x = (float)l; break;
   case Ocvts32f:   x = (int)intconval(lr); break;
   case Ocvtu32f:   x = (int)intconval(lr); break;
   case Ocvts64f:   x = (s64int)intconval(lr); break;
   case Ocvtu64f:   x = (u64int)intconval(lr); break;
   case Oadd: x = l + r; break;
   case Osub: x = l - r; break;
   case Omul: x = l * r; break;
   case Odiv: x = l / r; break;
   case Oequ: xi = l == r; goto Cmp;
   case Oneq: xi = l != r; goto Cmp;
   case Olth: xi = l < r; goto Cmp;
   case Ogth: xi = l > r; goto Cmp;
   case Olte: xi = l <= r; goto Cmp;
   case Ogte: xi = l >= r; Cmp: return mkref(RICON, xi);
   default: assert(0);
   }
   if (!w) x = (float)x;
   return mkfltcon(k, x);
}

bool
foldbinop(Ref *to, enum op op, enum irclass k, Ref l, Ref r)
{
   if (!oisarith(op))
      return 0;
   if (!isnumcon(l) || !isnumcon(r)) return 0;
   if (in_range(op, Odiv, Ourem) && kisint(k) && intconval(r) == 0)
      return 0;
   if (kisint(k))
      *to = foldint(op, k, l, r);
   else
      *to = foldflt(op, k, l, r);
   return 1;
}

bool
foldunop(Ref *to, enum op op, enum irclass k, Ref a)
{
   if (!isnumcon(a)) return 0;
   if (op != Ocopy && !oisarith(op))
      return 0;
   if (kisint(k))
      *to = foldint(op, k, a, ZEROREF);
   else
      *to = foldflt(op, k, a, ZEROREF);
   return 1;
}

/* vim:set ts=3 sw=3 expandtab: */