gcc/

	Backport from trunk r235478.
	2016-04-27  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	* params.def (MAX_PARTITION_SIZE): New param.
	* invoke.texi: Document lto-max-partition.

	gcc/lto/
	Backport from trunk r235478.
	2016-04-27  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	* lto-partition.h (lto_balanced_map): New parameter.
	* lto-partition.c (lto_balanced_map): New parameter
	max_partition_size.
	Check if partition size is greater than max_partition_size.
	* lto.c (do_whole_program_analysis): Adjust calls to
	lto_balanced_map() to pass 2nd argument.

Change-Id: I4a8692c9278b4563ac2d6f97a5fbb586b4eb4450

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 821f8fd..4afa32c 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -9477,6 +9477,11 @@ Size of minimal partition for WHOPR (in estimated instructions).
 This prevents expenses of splitting very small programs into too many
 partitions.
 
+@item lto-max-partition
+Size of max partition for WHOPR (in estimated instructions).
+to provide an upper bound for individual size of partition.
+Meant to be used only with balanced partitioning.
+
 @item cxx-max-namespaces-for-diagnostic-help
 The maximum number of namespaces to consult for suggestions when C++
 name lookup fails for an identifier.  The default is 1000.

diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c
index 9eb63c2..c191d24 100644 (file)
--- a/gcc/lto/lto-partition.c
+++ b/gcc/lto/lto-partition.c
@@ -447,7 +447,7 @@ add_sorted_nodes (vec<symtab_node *> &next_nodes, ltrans_partition partition)
    and in-partition calls was reached.  */
 
 void
-lto_balanced_map (int n_lto_partitions)
+lto_balanced_map (int n_lto_partitions, int max_partition_size)
 {
   int n_nodes = 0;
   int n_varpool_nodes = 0, varpool_pos = 0, best_varpool_pos = 0;
@@ -511,6 +511,9 @@ lto_balanced_map (int n_lto_partitions)
   varpool_order.qsort (varpool_node_cmp);
 
   /* Compute partition size and create the first partition.  */
+  if (PARAM_VALUE (MIN_PARTITION_SIZE) > max_partition_size)
+    fatal_error (input_location, "min partition size cannot be greater than max partition size");
+
   partition_size = total_size / n_lto_partitions;
   if (partition_size < PARAM_VALUE (MIN_PARTITION_SIZE))
     partition_size = PARAM_VALUE (MIN_PARTITION_SIZE);
@@ -719,7 +722,8 @@ lto_balanced_map (int n_lto_partitions)
                 best_cost, best_internal, best_i);
       /* Partition is too large, unwind into step when best cost was reached and
         start new partition.  */
-      if (partition->insns > 2 * partition_size)
+      if (partition->insns > 2 * partition_size
+         || partition->insns > max_partition_size)
        {
          if (best_i != i)
            {

diff --git a/gcc/lto/lto-partition.h b/gcc/lto/lto-partition.h
index 31e3764..f7abe62 100644 (file)
--- a/gcc/lto/lto-partition.h
+++ b/gcc/lto/lto-partition.h
@@ -35,7 +35,7 @@ extern vec<ltrans_partition> ltrans_partitions;
 
 void lto_1_to_1_map (void);
 void lto_max_map (void);
-void lto_balanced_map (int);
+void lto_balanced_map (int, int);
 void lto_promote_cross_file_statics (void);
 void free_ltrans_partitions (void);
 void lto_promote_statics_nonwpa (void);

diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
index 9dd513f..af735cb 100644 (file)
--- a/gcc/lto/lto.c
+++ b/gcc/lto/lto.c
@@ -3117,9 +3117,10 @@ do_whole_program_analysis (void)
   else if (flag_lto_partition == LTO_PARTITION_MAX)
     lto_max_map ();
   else if (flag_lto_partition == LTO_PARTITION_ONE)
-    lto_balanced_map (1);
+    lto_balanced_map (1, INT_MAX);
   else if (flag_lto_partition == LTO_PARTITION_BALANCED)
-    lto_balanced_map (PARAM_VALUE (PARAM_LTO_PARTITIONS));
+    lto_balanced_map (PARAM_VALUE (PARAM_LTO_PARTITIONS),
+                     PARAM_VALUE (MAX_PARTITION_SIZE));
   else
     gcc_unreachable ();
 

diff --git a/gcc/params.def b/gcc/params.def
index dbff305..eceee32 100644 (file)
--- a/gcc/params.def
+++ b/gcc/params.def
@@ -1029,6 +1029,11 @@ DEFPARAM (MIN_PARTITION_SIZE,
          "Minimal size of a partition for LTO (in estimated instructions).",
          1000, 0, 0)
 
+DEFPARAM (MAX_PARTITION_SIZE,
+         "lto-max-partition",
+         "Maximal size of a partition for LTO (in estimated instructions).",
+         1000000, 0, INT_MAX)
+
 /* Diagnostic parameters.  */
 
 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,