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[6/7] Add a helper for getting the overall alignment of a DR
- From: Richard Sandiford <richard dot sandiford at linaro dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 03 Jul 2017 08:40:25 +0100
- Subject: [6/7] Add a helper for getting the overall alignment of a DR
- Authentication-results: sourceware.org; auth=none
This combines the information from previous patches to give a guaranteed
alignment for the DR as a whole. This should be a bit safer than using
base_element_aligned, since that only really took the base into account
(not the init or offset).
Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
Richard
2017-07-03 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* tree-data-ref.h (dr_alignment): Declare.
* tree-data-ref.c (dr_alignment): New function.
* tree-vectorizer.h (dataref_aux): Remove base_element_aligned.
* tree-vect-data-refs.c (vect_compute_data_ref_alignment): Don't
set it.
* tree-vect-stmts.c (vectorizable_store): Use dr_alignment.
Index: gcc/tree-data-ref.h
===================================================================
--- gcc/tree-data-ref.h 2017-07-03 08:17:58.418572314 +0100
+++ gcc/tree-data-ref.h 2017-07-03 08:18:29.775412176 +0100
@@ -405,6 +405,16 @@ extern bool compute_all_dependences (vec
vec<loop_p>, bool);
extern tree find_data_references_in_bb (struct loop *, basic_block,
vec<data_reference_p> *);
+extern unsigned int dr_alignment (innermost_loop_behavior *);
+
+/* Return the alignment in bytes that DR is guaranteed to have at all
+ times. */
+
+inline unsigned int
+dr_alignment (data_reference *dr)
+{
+ return dr_alignment (&DR_INNERMOST (dr));
+}
extern bool dr_may_alias_p (const struct data_reference *,
const struct data_reference *, bool);
Index: gcc/tree-data-ref.c
===================================================================
--- gcc/tree-data-ref.c 2017-07-03 08:17:58.418572314 +0100
+++ gcc/tree-data-ref.c 2017-07-03 08:17:59.017546839 +0100
@@ -4769,6 +4769,30 @@ find_data_references_in_loop (struct loo
return NULL_TREE;
}
+/* Return the alignment in bytes that DRB is guaranteed to have at all
+ times. */
+
+unsigned int
+dr_alignment (innermost_loop_behavior *drb)
+{
+ /* Get the alignment of BASE_ADDRESS + INIT. */
+ unsigned int alignment = drb->base_alignment;
+ unsigned int misalignment = (drb->base_misalignment
+ + TREE_INT_CST_LOW (drb->init));
+ if (misalignment != 0)
+ alignment = MIN (alignment, misalignment & -misalignment);
+
+ /* Cap it to the alignment of OFFSET. */
+ if (!integer_zerop (drb->offset))
+ alignment = MIN (alignment, drb->offset_alignment);
+
+ /* Cap it to the alignment of STEP. */
+ if (!integer_zerop (drb->step))
+ alignment = MIN (alignment, drb->step_alignment);
+
+ return alignment;
+}
+
/* Recursive helper function. */
static bool
Index: gcc/tree-vectorizer.h
===================================================================
--- gcc/tree-vectorizer.h 2017-07-03 08:17:58.419572272 +0100
+++ gcc/tree-vectorizer.h 2017-07-03 08:18:09.031167838 +0100
@@ -752,8 +752,6 @@ struct dataref_aux {
int misalignment;
/* If true the alignment of base_decl needs to be increased. */
bool base_misaligned;
- /* If true we know the base is at least vector element alignment aligned. */
- bool base_element_aligned;
tree base_decl;
};
Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c 2017-07-03 08:17:58.419572272 +0100
+++ gcc/tree-vect-data-refs.c 2017-07-03 08:17:59.018546796 +0100
@@ -731,12 +731,6 @@ vect_compute_data_ref_alignment (struct
unsigned int base_alignment = drb->base_alignment;
unsigned int base_misalignment = drb->base_misalignment;
unsigned HOST_WIDE_INT vector_alignment = TYPE_ALIGN_UNIT (vectype);
- unsigned HOST_WIDE_INT element_alignment
- = TYPE_ALIGN_UNIT (TREE_TYPE (vectype));
-
- if (base_alignment >= element_alignment
- && (base_misalignment & (element_alignment - 1)) == 0)
- DR_VECT_AUX (dr)->base_element_aligned = true;
if (drb->offset_alignment < vector_alignment
|| !step_preserves_misalignment_p
@@ -797,7 +791,6 @@ vect_compute_data_ref_alignment (struct
DR_VECT_AUX (dr)->base_decl = base;
DR_VECT_AUX (dr)->base_misaligned = true;
- DR_VECT_AUX (dr)->base_element_aligned = true;
base_misalignment = 0;
}
unsigned int misalignment = (base_misalignment
Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c 2017-07-03 08:07:42.512875037 +0100
+++ gcc/tree-vect-stmts.c 2017-07-03 08:17:59.019546754 +0100
@@ -6359,11 +6359,7 @@ vectorizable_store (gimple *stmt, gimple
misalign = 0;
else if (DR_MISALIGNMENT (first_dr) == -1)
{
- if (DR_VECT_AUX (first_dr)->base_element_aligned)
- align = TYPE_ALIGN_UNIT (elem_type);
- else
- align = get_object_alignment (DR_REF (first_dr))
- / BITS_PER_UNIT;
+ align = dr_alignment (vect_dr_behavior (first_dr));
misalign = 0;
TREE_TYPE (data_ref)
= build_aligned_type (TREE_TYPE (data_ref),
@@ -7435,11 +7431,7 @@ vectorizable_load (gimple *stmt, gimple_
}
else if (DR_MISALIGNMENT (first_dr) == -1)
{
- if (DR_VECT_AUX (first_dr)->base_element_aligned)
- align = TYPE_ALIGN_UNIT (elem_type);
- else
- align = (get_object_alignment (DR_REF (first_dr))
- / BITS_PER_UNIT);
+ align = dr_alignment (vect_dr_behavior (first_dr));
misalign = 0;
TREE_TYPE (data_ref)
= build_aligned_type (TREE_TYPE (data_ref),