Fix PR45199: do not aggregate memory accesses to the same array for -ftree-loop-distribute-patterns

2010-11-30  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/45199
	* tree-data-ref.c (mem_write_stride_of_same_size_as_unit_type_p): New.
	(stores_zero_from_loop): Call
	mem_write_stride_of_same_size_as_unit_type_p.
	* tree-data-ref.h (stride_of_unit_type_p): New.
	* tree-loop-distribution.c (generate_memset_zero): Simplified.
	Call stride_of_unit_type_p.
	(build_rdg_partition_for_component): Do not call
	rdg_flag_similar_memory_accesses when
	flag_tree_loop_distribute_patterns is set.

	* gcc.dg/tree-ssa/ldist-15.c: New.
	* gcc.dg/tree-ssa/ldist-16.c: New.
	* gfortran.dg/ldist-pr45199.f: New.

From-SVN: r167380

1 files changed, 23 insertions, 1 deletions

diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index 3cee320846b..094d16822a9 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -4974,6 +4974,27 @@ stores_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
   free (bbs);
 }
 
+/* Returns true when STMT is an assignment that contains a data
+   reference on its LHS with a stride of the same size as its unit
+   type.  */
+
+static bool
+mem_write_stride_of_same_size_as_unit_type_p (gimple stmt)
+{
+  struct data_reference *dr = XCNEW (struct data_reference);
+  tree op0 = gimple_assign_lhs (stmt);
+  bool res;
+
+  DR_STMT (dr) = stmt;
+  DR_REF (dr) = op0;
+
+  res = dr_analyze_innermost (dr)
+    && stride_of_unit_type_p (DR_STEP (dr), TREE_TYPE (op0));
+
+  free_data_ref (dr);
+  return res;
+}
+
 /* Initialize STMTS with all the statements of LOOP that contain a
    store to memory of the form "A[i] = 0".  */
 
@@ -4994,7 +5015,8 @@ stores_zero_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
 	  && is_gimple_assign (stmt)
 	  && gimple_assign_rhs_code (stmt) == INTEGER_CST
 	  && (op = gimple_assign_rhs1 (stmt))
-	  && (integer_zerop (op) || real_zerop (op)))
+	  && (integer_zerop (op) || real_zerop (op))
+	  && mem_write_stride_of_same_size_as_unit_type_p (stmt))
 	VEC_safe_push (gimple, heap, *stmts, gsi_stmt (si));
 
   free (bbs);