Limit the number of parameters per SCoP.

2010-03-09  Sebastian Pop  <sebastian.pop@amd.com>

	* graphite-sese-to-poly.c (build_poly_scop): Limit scops following
	the number of parameters in the scop.  Use as an upper bound
	PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS.
	* params.def (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS): Declared.
	* doc/invoke.texi: Document it.

From-SVN: r157431

diff --git a/gcc/ChangeLog.graphite b/gcc/ChangeLog.graphite
index 9dcdcdab99b52b5fa0d94bd5e4de0f3fe0fa8003..61b463bb685b85137c06c0201c79268a8e4fd3fd 100644 (file)
--- a/gcc/ChangeLog.graphite
+++ b/gcc/ChangeLog.graphite
@@ -1,3 +1,11 @@
+2010-03-09  Sebastian Pop  <sebastian.pop@amd.com>
+
+       * graphite-sese-to-poly.c (build_poly_scop): Limit scops following
+       the number of parameters in the scop.  Use as an upper bound
+       PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS.
+       * params.def (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS): Declared.
+       * doc/invoke.texi: Document it.
+
 2010-03-05  Sebastian Pop  <sebastian.pop@amd.com>
 
        * graphite-sese-to-poly.c (add_param_constraints): Use

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 060be884e0ca8c08de142b0eded973d670ad6425..21597017b539c872fb297f400bc31c5787f51093 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -8492,6 +8492,10 @@ parameters only when their cumulative size is less or equal to
 @option{ipa-sra-ptr-growth-factor} times the size of the original
 pointer parameter.
 
+@item graphite-max-nb-scop-params
+To avoid exponential effects in the Graphite loop transforms, the
+number of parameters in a SCoP is bounded by 10.
+
 @end table
 @end table
 

diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c
index 11bddf85fd9096e109c7feb1f0f7090e9ce609c1..ae4a083663a2607b020a1603f7ef812a4b44b1c6 100644 (file)
--- a/gcc/graphite-sese-to-poly.c
+++ b/gcc/graphite-sese-to-poly.c
@@ -2937,6 +2937,7 @@ build_poly_scop (scop_p scop)
 {
   sese region = SCOP_REGION (scop);
   sbitmap reductions = sbitmap_alloc (last_basic_block * 2);
+  graphite_dim_t max_dim;
 
   sbitmap_zero (reductions);
   rewrite_commutative_reductions_out_of_ssa (region, reductions);
@@ -2960,6 +2961,10 @@ build_poly_scop (scop_p scop)
   build_sese_conditions (region);
   find_scop_parameters (scop);
 
+  max_dim = PARAM_VALUE (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS);
+  if (scop_nb_params (scop) > max_dim)
+    return false;
+
   build_scop_iteration_domain (scop);
   build_scop_context (scop);
 

diff --git a/gcc/params.def b/gcc/params.def
index 07bfb901f0ba8a4143a7fc8522dd2105f7d37469..f6f549c1466b203ea695564b4459e6903b9c3121 100644 (file)
--- a/gcc/params.def
+++ b/gcc/params.def
@@ -745,6 +745,13 @@ DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
          "size of tiles for loop blocking",
          51, 0, 0)
 
+/* Maximal number of parameters that we allow in a SCoP.  */
+
+DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
+         "graphite-max-nb-scop-params",
+         "maximal number of parameters in a SCoP",
+         10, 0, 0)
+
 /* Avoid doing loop invariant motion on very large loops.  */
 
 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,