isl_power_templ.c

   1 #include <isl_val_private.h>
   2
   3 #define xFN(TYPE,NAME) TYPE ## _ ## NAME
   4 #define FN(TYPE,NAME) xFN(TYPE,NAME)
   5
   6 /* Helper function for isl_*_fixed_power that applies (a copy of) "map2"
   7  * to the range of "map1" and returns the result.
   8  *
   9  * The result is coalesced in an attempt to reduce the number of disjuncts
  10  * that result from repeated applications.
  11  * Similarly, look for implicit equality constraints in an attempt
  12  * to reduce the number of local variables that get introduced
  13  * during the repeated applications.
  14  */
  15 static __isl_give TYPE *FN(TYPE,fixed_power_apply)(__isl_take TYPE *map1,
  16         __isl_keep TYPE *map2)
  17 {
  18         TYPE *res;
  19
  20         res = FN(TYPE,apply_range)(map1, FN(TYPE,copy)(map2));
  21         res = FN(TYPE,detect_equalities)(res);
  22         res = FN(TYPE,coalesce)(res);
  23
  24         return res;
  25 }
  26
  27 /* Compute the given non-zero power of "map" and return the result.
  28  * If the exponent "exp" is negative, then the -exp th power of the inverse
  29  * relation is computed.
  30  */
  31 __isl_give TYPE *FN(TYPE,fixed_power)(__isl_take TYPE *map, isl_int exp)
  32 {
  33         isl_ctx *ctx;
  34         TYPE *res = NULL;
  35         isl_int r;
  36
  37         if (!map)
  38                 return NULL;
  39
  40         ctx = FN(TYPE,get_ctx)(map);
  41         if (isl_int_is_zero(exp))
  42                 isl_die(ctx, isl_error_invalid,
  43                         "expecting non-zero exponent", goto error);
  44
  45         if (isl_int_is_neg(exp)) {
  46                 isl_int_neg(exp, exp);
  47                 map = FN(TYPE,reverse)(map);
  48                 return FN(TYPE,fixed_power)(map, exp);
  49         }
  50
  51         isl_int_init(r);
  52         for (;;) {
  53                 isl_int_fdiv_r(r, exp, ctx->two);
  54
  55                 if (!isl_int_is_zero(r)) {
  56                         if (!res)
  57                                 res = FN(TYPE,copy)(map);
  58                         else
  59                                 res = FN(TYPE,fixed_power_apply)(res, map);
  60                         if (!res)
  61                                 break;
  62                 }
  63
  64                 isl_int_fdiv_q(exp, exp, ctx->two);
  65                 if (isl_int_is_zero(exp))
  66                         break;
  67
  68                 map = FN(TYPE,fixed_power_apply)(map, map);
  69         }
  70         isl_int_clear(r);
  71
  72         FN(TYPE,free)(map);
  73         return res;
  74 error:
  75         FN(TYPE,free)(map);
  76         return NULL;
  77 }
  78
  79 /* Compute the given non-zero power of "map" and return the result.
  80  * If the exponent "exp" is negative, then the -exp th power of the inverse
  81  * relation is computed.
  82  */
  83 __isl_give TYPE *FN(TYPE,fixed_power_val)(__isl_take TYPE *map,
  84         __isl_take isl_val *exp)
  85 {
  86         if (!map || !exp)
  87                 goto error;
  88         if (!isl_val_is_int(exp))
  89                 isl_die(FN(TYPE,get_ctx)(map), isl_error_invalid,
  90                         "expecting integer exponent", goto error);
  91         map = FN(TYPE,fixed_power)(map, exp->n);
  92         isl_val_free(exp);
  93         return map;
  94 error:
  95         FN(TYPE,free)(map);
  96         isl_val_free(exp);
  97         return NULL;
  98 }