pr45260 Don't generate prefetch if the address of base could not be taken.

	* tree-flow.h (may_be_nonaddressable_p): New definition. Make the
	existing static function global.

	*tree-ssa-loop-ivopts.c (may_be_nonaddressable_p): This function
	is changed to global.

	*tree-ssa-loop-prefetch.c (gather_memory_references_ref): Call
	may_be_nonaddressable_p on base, and don't collect this reference
	if the address of the base could not be taken.

From-SVN: r163475

gcc/ChangeLog

+2010-08-23  Changpeng Fang  <changpeng.fang@amd.com>
+
+	* tree-flow.h (may_be_nonaddressable_p): New definition. Make the
+	existing static function global.
+
+	*tree-ssa-loop-ivopts.c (may_be_nonaddressable_p): This function
+	is changed to global.
+
+	*tree-ssa-loop-prefetch.c (gather_memory_references_ref): Call
+	may_be_nonaddressable_p on base, and don't collect this reference
+	if the address of the base could not be taken.
+
 2010-08-23  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	* config/rs6000/rs6000.opt (-mveclibabi=mass): New option to

gcc/tree-flow.h

@@ -817,6 +817,7 @@ bool stmt_invariant_in_loop_p (struct loop *, gimple);
 bool multiplier_allowed_in_address_p (HOST_WIDE_INT, enum machine_mode,
 				      addr_space_t);
 unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode, bool);
+bool may_be_nonaddressable_p (tree expr);
 
 /* In tree-ssa-threadupdate.c.  */
 extern bool thread_through_all_blocks (bool);

gcc/tree-ssa-loop-ivopts.c

@@ -1640,7 +1640,7 @@ may_be_unaligned_p (tree ref, tree step)
 
 /* Return true if EXPR may be non-addressable.   */
 
-static bool
+bool
 may_be_nonaddressable_p (tree expr)
 {
   switch (TREE_CODE (expr))

gcc/tree-ssa-loop-prefetch.c

@@ -539,6 +539,10 @@ gather_memory_references_ref (struct loop *loop, struct mem_ref_group **refs,
   if (step == NULL_TREE)
     return false;
 
+  /* Stop if the address of BASE could not taken.  */
+  if (may_be_nonaddressable_p (base))
+    return false;
+
   /* Limit non-constant step prefetching only to the innermost loops.  */
   if (!cst_and_fits_in_hwi (step) && loop->inner != NULL)
     return false;