This patch makes vect_compute_data_ref_alignment treat DR_INIT as a
poly_int and handles cases in which the calculated misalignment might
not be constant.
2017-10-23 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* tree-vect-data-refs.c (vect_compute_data_ref_alignment):
Treat drb->init as a poly_int. Fail if its misalignment wrt
vector_alignment isn't known.
Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c 2017-10-23 17:22:18.234826257 +0100
+++ gcc/tree-vect-data-refs.c 2017-10-23 17:22:24.456074525 +0100
@@ -944,8 +944,8 @@ vect_compute_data_ref_alignment (struct
DR_VECT_AUX (dr)->base_misaligned = true;
base_misalignment = 0;
}
- unsigned int misalignment = (base_misalignment
- + TREE_INT_CST_LOW (drb->init));
+ poly_int64 misalignment
+ = base_misalignment + wi::to_poly_offset (drb->init).force_shwi ();
/* If this is a backward running DR then first access in the larger
vectype actually is N-1 elements before the address in the DR.
@@ -955,7 +955,21 @@ vect_compute_data_ref_alignment (struct
misalignment += ((TYPE_VECTOR_SUBPARTS (vectype) - 1)
* TREE_INT_CST_LOW (drb->step));
- SET_DR_MISALIGNMENT (dr, misalignment & (vector_alignment - 1));
+ unsigned int const_misalignment;
+ if (!known_misalignment (misalignment, vector_alignment,
+ &const_misalignment))
+ {
+ if (dump_enabled_p ())
+ {
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "Non-constant misalignment for access: ");
+ dump_generic_expr (MSG_MISSED_OPTIMIZATION, TDF_SLIM, ref);
+ dump_printf (MSG_MISSED_OPTIMIZATION, "\n");
+ }
+ return true;
+ }
+
+ SET_DR_MISALIGNMENT (dr, const_misalignment);
if (dump_enabled_p ())
{
