2013-10-01 Richard Biener <rguenther@suse.de>

	PR tree-optimization/58553
	* tree-loop-distribution.c (struct partition_s): Add niter member.
	(classify_partition): Populate niter member for the partition
	and properly identify whether the relevant store happens before
	or after the loop exit.
	(generate_memset_builtin): Use niter member from the partition.
	(generate_memcpy_builtin): Likewise.

	* gcc.dg/torture/pr58553.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@203054 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 16 deletions

diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 964131a1950..fe2f7b65b59 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -569,6 +569,7 @@ typedef struct partition_s
   /* data-references a kind != PKIND_NORMAL partition is about.  */
   data_reference_p main_dr;
   data_reference_p secondary_dr;
+  tree niter;
 } *partition_t;
 
 
@@ -848,21 +849,17 @@ generate_memset_builtin (struct loop *loop, partition_t partition)
 {
   gimple_stmt_iterator gsi;
   gimple stmt, fn_call;
-  tree nb_iter, mem, fn, nb_bytes;
+  tree mem, fn, nb_bytes;
   location_t loc;
   tree val;
 
   stmt = DR_STMT (partition->main_dr);
   loc = gimple_location (stmt);
-  if (gimple_bb (stmt) == loop->latch)
-    nb_iter = number_of_latch_executions (loop);
-  else
-    nb_iter = number_of_exit_cond_executions (loop);
 
   /* The new statements will be placed before LOOP.  */
   gsi = gsi_last_bb (loop_preheader_edge (loop)->src);
 
-  nb_bytes = build_size_arg_loc (loc, partition->main_dr, nb_iter);
+  nb_bytes = build_size_arg_loc (loc, partition->main_dr, partition->niter);
   nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
 				       false, GSI_CONTINUE_LINKING);
   mem = build_addr_arg_loc (loc, partition->main_dr, nb_bytes);
@@ -908,21 +905,17 @@ generate_memcpy_builtin (struct loop *loop, partition_t partition)
 {
   gimple_stmt_iterator gsi;
   gimple stmt, fn_call;
-  tree nb_iter, dest, src, fn, nb_bytes;
+  tree dest, src, fn, nb_bytes;
   location_t loc;
   enum built_in_function kind;
 
   stmt = DR_STMT (partition->main_dr);
   loc = gimple_location (stmt);
-  if (gimple_bb (stmt) == loop->latch)
-    nb_iter = number_of_latch_executions (loop);
-  else
-    nb_iter = number_of_exit_cond_executions (loop);
 
   /* The new statements will be placed before LOOP.  */
   gsi = gsi_last_bb (loop_preheader_edge (loop)->src);
 
-  nb_bytes = build_size_arg_loc (loc, partition->main_dr, nb_iter);
+  nb_bytes = build_size_arg_loc (loc, partition->main_dr, partition->niter);
   nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
 				       false, GSI_CONTINUE_LINKING);
   dest = build_addr_arg_loc (loc, partition->main_dr, nb_bytes);
@@ -1125,6 +1118,7 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
   partition->kind = PKIND_NORMAL;
   partition->main_dr = NULL;
   partition->secondary_dr = NULL;
+  partition->niter = NULL_TREE;
 
   EXECUTE_IF_SET_IN_BITMAP (partition->stmts, 0, i, bi)
     {
@@ -1151,10 +1145,6 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
       || !flag_tree_loop_distribute_patterns)
     return;
 
-  nb_iter = number_of_exit_cond_executions (loop);
-  if (!nb_iter || nb_iter == chrec_dont_know)
-    return;
-
   /* Detect memset and memcpy.  */
   single_load = NULL;
   single_store = NULL;
@@ -1193,6 +1183,17 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
 	}
     }
 
+  if (!single_store)
+    return;
+
+  if (!dominated_by_p (CDI_DOMINATORS, single_exit (loop)->src,
+		       gimple_bb (DR_STMT (single_store))))
+    nb_iter = number_of_latch_executions (loop);
+  else
+    nb_iter = number_of_exit_cond_executions (loop);
+  if (!nb_iter || nb_iter == chrec_dont_know)
+    return;
+
   if (single_store && !single_load)
     {
       gimple stmt = DR_STMT (single_store);
@@ -1212,6 +1213,7 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
 	return;
       partition->kind = PKIND_MEMSET;
       partition->main_dr = single_store;
+      partition->niter = nb_iter;
     }
   else if (single_store && single_load)
     {
@@ -1268,6 +1270,7 @@ classify_partition (loop_p loop, struct graph *rdg, partition_t partition)
       partition->kind = PKIND_MEMCPY;
       partition->main_dr = single_store;
       partition->secondary_dr = single_load;
+      partition->niter = nb_iter;
     }
 }