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tree-vect-data-refs.c (vect_no_alias_p): New function.

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* tree-vect-data-refs.c (vect_no_alias_p): New function.
	(vect_prune_runtime_alias_test_list): Call vect_no_alias_p to
	resolve alias checks which are known at compilation time.
	Truncate vector LOOP_VINFO_MAY_ALIAS_DDRS(loop_vinfo) if all
	alias checks are resolved.  Move dump info for too many runtime
	alias checks to here...
	* tree-vect-loop.c (vect_analyze_loop_2): ...From here.

	gcc/testsuite
	* gcc.dg/vect/vect-35-big-array.c: Refine comment and test.
	* gcc.dg/vect/vect-35.c: Ditto.
	* gcc.dg/vect/vect-alias-check-2.c: New test.

From-SVN: r238301
This commit is contained in:
Bin Cheng 2016-07-13 15:06:40 +00:00 • committed by Bin Cheng
parent 65f18bc635
commit 6fa3d4b4a7
7 changed files with 130 additions and 19 deletions
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10
gcc/ChangeLog
View file

@ -1,3 +1,13 @@
2016-07-13 Bin Cheng <bin.cheng@arm.com>
* tree-vect-data-refs.c (vect_no_alias_p): New function.
(vect_prune_runtime_alias_test_list): Call vect_no_alias_p to
resolve alias checks which are known at compilation time.
Truncate vector LOOP_VINFO_MAY_ALIAS_DDRS(loop_vinfo) if all
alias checks are resolved. Move dump info for too many runtime
alias checks to here...
* tree-vect-loop.c (vect_analyze_loop_2): ...From here.
2016-07-13 Richard Biener <rguenther@suse.de>
PR tree-optimization/24574

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2016-07-13 Bin Cheng <bin.cheng@arm.com>
* gcc.dg/vect/vect-35-big-array.c: Refine comment and test.
* gcc.dg/vect/vect-35.c: Ditto.
* gcc.dg/vect/vect-alias-check-2.c: New test.
2016-07-13 Martin Liska <mliska@suse.cz>
* gfortran.dg/ldist-1.f90: Revert change introduces in r238114.

8
gcc/testsuite/gcc.dg/vect/vect-35-big-array.c
View file

@ -21,7 +21,9 @@ int main1 ()
}
/* Dependence analysis fails cause s.a and s.b may overlap.
Use runtime aliasing test with versioning. */
Try to use runtime aliasing test with versioning, and
later versioning/vectorization are skipped because the
overlap is proven at compilation time. */
for (i = 0; i < N; i++)
{
s.a[i] = s.b[i] + 1;
@ -45,5 +47,5 @@ int main (void)
}
/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" { xfail { ia64-*-* sparc*-*-* } } } } */
/* { dg-final { scan-tree-dump-times "can't determine dependence between" 1 "vect" } } */
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail { ia64-*-* sparc*-*-* } } } } */
/* { dg-final { scan-tree-dump "can't determine dependence between" "vect" } } */

6
gcc/testsuite/gcc.dg/vect/vect-35.c
View file

@ -21,7 +21,9 @@ int main1 ()
}
/* Dependence analysis fails cause s.a and s.b may overlap.
Use runtime aliasing test with versioning. */
Try to use runtime aliasing test with versioning, and
later versioning/vectorization are skipped because the
overlap is proven at compilation time. */
for (i = 0; i < N; i++)
{
s.a[i] = s.b[i] + 1;
@ -45,5 +47,5 @@ int main (void)
}
/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" { xfail { ia64-*-* sparc*-*-* } } } } */
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { xfail { ia64-*-* sparc*-*-* } } } } */
/* { dg-final { scan-tree-dump "can't determine dependence between" "vect" } } */

19
gcc/testsuite/gcc.dg/vect/vect-alias-check-2.c Normal file
View file

@ -0,0 +1,19 @@
/* { dg-do compile } */
/* { dg-require-effective-target vect_int_mult } */
int a [128];
int b[128] = {0};
int foo (void)
{
int k;
for(k=0; k<64; k++)
{
b[k] = 10 - b[127-k];
a[k] = b[k] * 3;
a[127-k] = b[127-k] * 2;
}
}
/* { dg-final { scan-tree-dump-not "versioning for alias checks." "vect" } } */

90
gcc/tree-vect-data-refs.c
View file

@ -2938,6 +2938,56 @@ vect_vfa_segment_size (struct data_reference *dr, tree length_factor)
return segment_length;
}
/* Function vect_no_alias_p.
Given data references A and B with equal base and offset, the alias
relation can be decided at compilation time, return TRUE if they do
not alias to each other; return FALSE otherwise. SEGMENT_LENGTH_A
and SEGMENT_LENGTH_B are the memory lengths accessed by A and B
respectively. */
static bool
vect_no_alias_p (struct data_reference *a, struct data_reference *b,
tree segment_length_a, tree segment_length_b)
{
gcc_assert (TREE_CODE (DR_INIT (a)) == INTEGER_CST
&& TREE_CODE (DR_INIT (b)) == INTEGER_CST);
if (tree_int_cst_equal (DR_INIT (a), DR_INIT (b)))
return false;
tree seg_a_min = DR_INIT (a);
tree seg_a_max = fold_build2 (PLUS_EXPR, TREE_TYPE (seg_a_min),
seg_a_min, segment_length_a);
/* For negative step, we need to adjust address range by TYPE_SIZE_UNIT
bytes, e.g., int a[3] -> a[1] range is [a+4, a+16) instead of
[a, a+12) */
if (tree_int_cst_compare (DR_STEP (a), size_zero_node) < 0)
{
tree unit_size = TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (a)));
seg_a_min = fold_build2 (PLUS_EXPR, TREE_TYPE (seg_a_max),
seg_a_max, unit_size);
seg_a_max = fold_build2 (PLUS_EXPR, TREE_TYPE (DR_INIT (a)),
DR_INIT (a), unit_size);
}
tree seg_b_min = DR_INIT (b);
tree seg_b_max = fold_build2 (PLUS_EXPR, TREE_TYPE (seg_b_min),
seg_b_min, segment_length_b);
if (tree_int_cst_compare (DR_STEP (b), size_zero_node) < 0)
{
tree unit_size = TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (b)));
seg_b_min = fold_build2 (PLUS_EXPR, TREE_TYPE (seg_b_max),
seg_b_max, unit_size);
seg_b_max = fold_build2 (PLUS_EXPR, TREE_TYPE (DR_INIT (b)),
DR_INIT (b), unit_size);
}
if (tree_int_cst_le (seg_a_max, seg_b_min)
|| tree_int_cst_le (seg_b_max, seg_a_min))
return true;
return false;
}
/* Function vect_prune_runtime_alias_test_list.
Prune a list of ddrs to be tested at run-time by versioning for alias.
@ -3030,15 +3080,33 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
segment_length_a = vect_vfa_segment_size (dr_a, length_factor);
segment_length_b = vect_vfa_segment_size (dr_b, length_factor);
comp_res = compare_tree (DR_BASE_ADDRESS (dr_a), DR_BASE_ADDRESS (dr_b));
if (comp_res == 0)
comp_res = compare_tree (DR_OFFSET (dr_a), DR_OFFSET (dr_b));
/* Alias is known at compilation time. */
if (comp_res == 0
&& TREE_CODE (DR_STEP (dr_a)) == INTEGER_CST
&& TREE_CODE (DR_STEP (dr_b)) == INTEGER_CST
&& TREE_CODE (segment_length_a) == INTEGER_CST
&& TREE_CODE (segment_length_b) == INTEGER_CST)
{
if (vect_no_alias_p (dr_a, dr_b, segment_length_a, segment_length_b))
continue;
if (dump_enabled_p ())
dump_printf_loc (MSG_NOTE, vect_location,
"not vectorized: compilation time alias.\n");
return false;
}
dr_with_seg_len_pair_t dr_with_seg_len_pair
(dr_with_seg_len (dr_a, segment_length_a),
dr_with_seg_len (dr_b, segment_length_b));
/* Canonicalize pairs by sorting the two DR members. */
comp_res = compare_tree (DR_BASE_ADDRESS (dr_a), DR_BASE_ADDRESS (dr_b));
if (comp_res > 0
|| (comp_res == 0
&& compare_tree (DR_OFFSET (dr_a), DR_OFFSET (dr_b)) > 0))
if (comp_res > 0)
std::swap (dr_with_seg_len_pair.first, dr_with_seg_len_pair.second);
comp_alias_ddrs.safe_push (dr_with_seg_len_pair);
@ -3187,7 +3255,19 @@ vect_prune_runtime_alias_test_list (loop_vec_info loop_vinfo)
may_alias_ddrs.length (), comp_alias_ddrs.length ());
if ((int) comp_alias_ddrs.length () >
PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS))
return false;
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"number of versioning for alias "
"run-time tests exceeds %d "
"(--param vect-max-version-for-alias-checks)\n",
PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS));
return false;
}
/* All alias checks have been resolved at compilation time. */
if (!comp_alias_ddrs.length ())
LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo).truncate (0);
return true;
}

10
gcc/tree-vect-loop.c
View file

@ -1961,15 +1961,7 @@ start_over:
since we use grouping information gathered by interleaving analysis. */
ok = vect_prune_runtime_alias_test_list (loop_vinfo);
if (!ok)
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"number of versioning for alias "
"run-time tests exceeds %d "
"(--param vect-max-version-for-alias-checks)\n",
PARAM_VALUE (PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS));
return false;
}
return false;
/* This pass will decide on using loop versioning and/or loop peeling in
order to enhance the alignment of data references in the loop. */