/* Heuristics and transform for loop blocking and strip mining on
polyhedral representation.
- Copyright (C) 2009 Free Software Foundation, Inc.
+ Copyright (C) 2009, 2010 Free Software Foundation, Inc.
Contributed by Sebastian Pop <sebastian.pop@amd.com> and
Pranav Garg <pranav.garg2107@gmail.com>.
#include "config.h"
#include "system.h"
#include "coretypes.h"
-#include "tm.h"
-#include "ggc.h"
-#include "tree.h"
-#include "rtl.h"
-#include "output.h"
-#include "basic-block.h"
-#include "diagnostic.h"
#include "tree-flow.h"
-#include "toplev.h"
#include "tree-dump.h"
-#include "timevar.h"
#include "cfgloop.h"
#include "tree-chrec.h"
#include "tree-data-ref.h"
-#include "tree-scalar-evolution.h"
-#include "tree-pass.h"
-#include "domwalk.h"
-#include "value-prof.h"
-#include "pointer-set.h"
-#include "gimple.h"
-#include "params.h"
+#include "sese.h"
#ifdef HAVE_cloog
-#include "cloog/cloog.h"
#include "ppl_c.h"
-#include "sese.h"
#include "graphite-ppl.h"
-#include "graphite.h"
#include "graphite-poly.h"
-/* Strip mines with a factor STRIDE the loop around PBB at depth
- LOOP_DEPTH. The following example comes from the wiki page:
+/* Strip mines with a factor STRIDE the scattering (time) dimension
+ around PBB at depth TIME_DEPTH.
+
+ The following example comes from the wiki page:
http://gcc.gnu.org/wiki/Graphite/Strip_mine
The strip mine of a loop with a tile of 64 can be obtained with a
# }
*/
-static bool
-pbb_strip_mine_loop_depth (poly_bb_p pbb, int loop_depth, int stride)
+static void
+pbb_strip_mine_time_depth (poly_bb_p pbb, int time_depth, int stride)
{
- ppl_dimension_type iter, dim;
+ ppl_dimension_type iter, dim, strip;
ppl_Polyhedron_t res = PBB_TRANSFORMED_SCATTERING (pbb);
- ppl_dimension_type strip = psct_scattering_dim_for_loop_depth (pbb,
- loop_depth);
+ /* STRIP is the dimension that iterates with stride STRIDE. */
+ /* ITER is the dimension that enumerates single iterations inside
+ one strip that has at most STRIDE iterations. */
+ strip = time_depth;
+ iter = strip + 2;
psct_add_scattering_dimension (pbb, strip);
+ psct_add_scattering_dimension (pbb, strip + 1);
- iter = psct_iterator_dim (pbb, loop_depth);
ppl_Polyhedron_space_dimension (res, &dim);
/* Lower bound of the striped loop. */
ppl_delete_Constraint (new_cstr);
}
- return true;
+ /* Static scheduling for ITER level.
+ This is mandatory to keep the 2d + 1 canonical scheduling format. */
+ {
+ ppl_Constraint_t new_cstr;
+ ppl_Linear_Expression_t expr;
+
+ ppl_new_Linear_Expression_with_dimension (&expr, dim);
+ ppl_set_coef (expr, strip + 1, 1);
+ ppl_set_inhomogeneous (expr, 0);
+
+ ppl_new_Constraint (&new_cstr, expr, PPL_CONSTRAINT_TYPE_EQUAL);
+ ppl_delete_Linear_Expression (expr);
+ ppl_Polyhedron_add_constraint (res, new_cstr);
+ ppl_delete_Constraint (new_cstr);
+ }
}
-/* Returns true when strip mining with STRIDE of the loop around PBB
- at depth LOOP_DEPTH is profitable. */
+/* Returns true when strip mining with STRIDE of the loop LST is
+ profitable. */
static bool
-pbb_strip_mine_profitable_p (poly_bb_p pbb,
- graphite_dim_t loop_depth,
- int stride)
+lst_strip_mine_profitable_p (lst_p lst, int stride)
{
- Value niter, strip_stride;
+ mpz_t niter, strip_stride;
bool res;
- value_init (strip_stride);
- value_init (niter);
- value_set_si (strip_stride, stride);
- pbb_number_of_iterations (pbb, loop_depth, niter);
- res = value_gt (niter, strip_stride);
- value_clear (strip_stride);
- value_clear (niter);
+ gcc_assert (LST_LOOP_P (lst));
+ mpz_init (strip_stride);
+ mpz_init (niter);
+ mpz_set_si (strip_stride, stride);
+ lst_niter_for_loop (lst, niter);
+ res = (mpz_cmp (niter, strip_stride) > 0);
+
+ mpz_clear (strip_stride);
+ mpz_clear (niter);
return res;
}
-/* Strip mines all the loops around PBB. Nothing profitable in all this:
- this is just a driver function. */
+/* Strip-mines all the loops of LST with STRIDE. Return the number of
+ loops strip-mined. */
-static bool
-pbb_do_strip_mine (poly_bb_p pbb)
+static int
+lst_do_strip_mine_loop (lst_p lst, int depth, int stride)
{
- graphite_dim_t loop_depth;
- int stride = 64;
- bool transform_done = false;
+ int i;
+ lst_p l;
+ poly_bb_p pbb;
+
+ if (!lst)
+ return 0;
+
+ if (LST_LOOP_P (lst))
+ {
+ int res = 0;
- for (loop_depth = 0; loop_depth < pbb_dim_iter_domain (pbb); loop_depth++)
- if (pbb_strip_mine_profitable_p (pbb, loop_depth, stride))
- transform_done |= pbb_strip_mine_loop_depth (pbb, loop_depth, stride);
+ FOR_EACH_VEC_ELT (lst_p, LST_SEQ (lst), i, l)
+ res += lst_do_strip_mine_loop (l, depth, stride);
- return transform_done;
+ return res;
+ }
+
+ pbb = LST_PBB (lst);
+ pbb_strip_mine_time_depth (pbb, psct_dynamic_dim (pbb, depth), stride);
+ return 1;
}
-/* Strip mines all the loops in SCOP. Nothing profitable in all this:
- this is just a driver function. */
+/* Strip-mines all the loops of LST with STRIDE. When STRIDE is zero,
+ read the stride from the PARAM_LOOP_BLOCK_TILE_SIZE. Return the
+ number of strip-mined loops.
-bool
-scop_do_strip_mine (scop_p scop)
+ Strip mining transforms a loop
+
+ | for (i = 0; i < N; i++)
+ | S (i);
+
+ into the following loop nest:
+
+ | for (k = 0; k < N; k += STRIDE)
+ | for (j = 0; j < STRIDE; j++)
+ | S (i = k + j);
+*/
+
+static int
+lst_do_strip_mine (lst_p lst, int stride)
{
- poly_bb_p pbb;
int i;
- bool transform_done = false;
+ lst_p l;
+ int res = 0;
+ int depth;
- for (i = 0; VEC_iterate (poly_bb_p, SCOP_BBS (scop), i, pbb); i++)
- transform_done |= pbb_do_strip_mine (pbb);
+ if (!stride)
+ stride = PARAM_VALUE (PARAM_LOOP_BLOCK_TILE_SIZE);
+
+ if (!lst
+ || !LST_LOOP_P (lst))
+ return false;
+
+ FOR_EACH_VEC_ELT (lst_p, LST_SEQ (lst), i, l)
+ res += lst_do_strip_mine (l, stride);
+
+ depth = lst_depth (lst);
+ if (depth >= 0
+ && lst_strip_mine_profitable_p (lst, stride))
+ {
+ res += lst_do_strip_mine_loop (lst, lst_depth (lst), stride);
+ lst_add_loop_under_loop (lst);
+ }
+
+ return res;
+}
- return transform_done;
+/* Strip mines all the loops in SCOP. Returns the number of
+ strip-mined loops. */
+
+int
+scop_do_strip_mine (scop_p scop, int stride)
+{
+ return lst_do_strip_mine (SCOP_TRANSFORMED_SCHEDULE (scop), stride);
+}
+
+/* Loop blocks all the loops in SCOP. Returns true when we manage to
+ block some loops. */
+
+bool
+scop_do_block (scop_p scop)
+{
+ store_scattering (scop);
+
+ /* If we don't strip mine at least two loops, or not interchange
+ loops, the strip mine alone will not be profitable, and the
+ transform is not a loop blocking: so revert the transform. */
+ if (lst_do_strip_mine (SCOP_TRANSFORMED_SCHEDULE (scop), 0) < 2
+ || scop_do_interchange (scop) == 0)
+ {
+ restore_scattering (scop);
+ return false;
+ }
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "SCoP will be loop blocked.\n");
+
+ return true;
}
#endif
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