Richard Biener <richard.guent...@gmail.com> writes:
> On Thu, Sep 14, 2017 at 4:05 PM, Richard Sandiford
> <richard.sandif...@linaro.org> wrote:
>> Richard Biener <richard.guent...@gmail.com> writes:
>>> On Thu, Sep 14, 2017 at 1:23 PM, Richard Sandiford
>>> <richard.sandif...@linaro.org> wrote:
>>>> This patch adds a helper function for getting the number of
>>>> bytes accessed by a scalar data reference, which helps when general
>>>> modes have a variable size.
>>>>
>>>> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
>>>> OK to install?
>>>
>>> Can you put it into tree-data-ref.h?
>>
>> The idea (which I forgot to say) was to collect the uses within the
>> vectoriser into one place so that we can assert in only one place
>> that the reference is constant-sized.
>>
>> A general data_reference can be variable-sized, so the guarantees
>> wouldn't be the same elsewhere.
>>
>> Would putting it in tree-vectorizer.h be OK?
>
> Maybe name it vect_get_scalar_dr_size then?
>
> Ok with that.
As discussed on IRC, I tried also using SCALAR_TYPE_MODE instead of
TYPE_MODE, to go with the new function name, but it turns out that
the mode can be a single-element vector instead of a "true" scalar.
This version of the patch sticks with vect_get_scalar_dr_size as
the name, but adds a comment to say that "scalar" includes "scalar
equivalent". Since SCALAR_TYPE_MODE is too strong an assertion,
I went with tree_to_uhwi instead.
As also discussed on IRC, it might be possible in current sources
to use SCALAR_TYPE_MODE (TREE_TYPE (STMT_VINFO_VECTYPE ...)) instead.
But SVE has extending loads and truncating stores, for which the DR size
will be different from the vector element size, so if we switch it now,
we'd have to switch back to the DR size again later.
(Sorry again for labouring such a simple change!)
Tested as before. OK to install?
Thanks,
Richard
2017-09-22 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* tree-vectorizer.h (vect_get_scalar_dr_size): New function.
* tree-vect-data-refs.c (vect_update_misalignment_for_peel): Use it.
(vect_enhance_data_refs_alignment): Likewise.
Index: gcc/tree-vectorizer.h
===================================================================
--- gcc/tree-vectorizer.h 2017-09-18 16:49:51.902170781 +0100
+++ gcc/tree-vectorizer.h 2017-09-22 08:58:24.308199570 +0100
@@ -1095,6 +1095,19 @@ vect_get_num_copies (loop_vec_info loop_
/ TYPE_VECTOR_SUBPARTS (vectype));
}
+/* Return the size of the value accessed by unvectorized data reference DR.
+ This is only valid once STMT_VINFO_VECTYPE has been calculated for the
+ associated gimple statement, since that guarantees that DR accesses
+ either a scalar or a scalar equivalent. ("Scalar equivalent" here
+ includes things like V1SI, which can be vectorized in the same way
+ as a plain SI.) */
+
+inline unsigned int
+vect_get_scalar_dr_size (struct data_reference *dr)
+{
+ return tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr))));
+}
+
/* Source location */
extern source_location vect_location;
Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c 2017-09-18 16:42:00.553203578 +0100
+++ gcc/tree-vect-data-refs.c 2017-09-22 08:58:24.308199570 +0100
@@ -955,7 +955,6 @@ vect_compute_data_ref_alignment (struct
return true;
}
-
/* Function vect_update_misalignment_for_peel.
Sets DR's misalignment
- to 0 if it has the same alignment as DR_PEEL,
@@ -975,8 +974,8 @@ vect_update_misalignment_for_peel (struc
unsigned int i;
vec<dr_p> same_aligned_drs;
struct data_reference *current_dr;
- int dr_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
- int dr_peel_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr_peel))));
+ int dr_size = vect_get_scalar_dr_size (dr);
+ int dr_peel_size = vect_get_scalar_dr_size (dr_peel);
stmt_vec_info stmt_info = vinfo_for_stmt (DR_STMT (dr));
stmt_vec_info peel_stmt_info = vinfo_for_stmt (DR_STMT (dr_peel));
@@ -1664,8 +1663,7 @@ vect_enhance_data_refs_alignment (loop_v
vectype = STMT_VINFO_VECTYPE (stmt_info);
nelements = TYPE_VECTOR_SUBPARTS (vectype);
- mis = DR_MISALIGNMENT (dr) / GET_MODE_SIZE (TYPE_MODE (
- TREE_TYPE (DR_REF (dr))));
+ mis = DR_MISALIGNMENT (dr) / vect_get_scalar_dr_size (dr);
if (DR_MISALIGNMENT (dr) != 0)
npeel_tmp = (negative ? (mis - nelements)
: (nelements - mis)) & (nelements - 1);
@@ -1937,8 +1935,7 @@ vect_enhance_data_refs_alignment (loop_v
updating DR_MISALIGNMENT values. The peeling factor is the
vectorization factor minus the misalignment as an element
count. */
- mis = DR_MISALIGNMENT (dr0);
- mis /= GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr0))));
+ mis = DR_MISALIGNMENT (dr0) / vect_get_scalar_dr_size (dr0);
npeel = ((negative ? mis - nelements : nelements - mis)
& (nelements - 1));
}
