[gcc r9-8248] Fix SLP downward group access classification [PR92420]
Richard Sandiford
rsandifo@gcc.gnu.org
Tue Feb 18 08:52:00 GMT 2020
https://gcc.gnu.org/g:2d8ea3a0a6095a56b7c59c50b1068d602cde934a
commit r9-8248-g2d8ea3a0a6095a56b7c59c50b1068d602cde934a
Author: Richard Sandiford <richard.sandiford@arm.com>
Date: Mon Nov 11 19:43:52 2019 +0000
Fix SLP downward group access classification [PR92420]
This PR was caused by the SLP handling in get_group_load_store_type
returning VMAT_CONTIGUOUS rather than VMAT_CONTIGUOUS_REVERSE for
downward groups.
A more elaborate fix would be to try to combine the reverse permutation
into SLP_TREE_LOAD_PERMUTATION for loads, but that's really a follow-on
optimisation and not backport material. It might also not necessarily
be a win, if the target supports (say) reversing and odd/even swaps
as independent permutes but doesn't recognise the combined form.
2020-02-18 Richard Sandiford <richard.sandiford@arm.com>
gcc/
Backport from mainline
2019-11-11 Richard Sandiford <richard.sandiford@arm.com>
PR tree-optimization/92420
* tree-vect-stmts.c (get_negative_load_store_type): Move further
up file.
(get_group_load_store_type): Use it for reversed SLP accesses.
gcc/testsuite/
PR tree-optimization/92420
* gcc.dg/vect/pr92420.c: New test.
Diff:
---
gcc/ChangeLog | 10 ++++
gcc/testsuite/ChangeLog | 5 ++
gcc/testsuite/gcc.dg/vect/pr92420.c | 48 ++++++++++++++++
gcc/tree-vect-stmts.c | 110 +++++++++++++++++++-----------------
4 files changed, 122 insertions(+), 51 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 967a9fb..8de0814 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,16 @@
2020-02-18 Richard Sandiford <richard.sandiford@arm.com>
Backport from mainline
+ 2019-11-11 Richard Sandiford <richard.sandiford@arm.com>
+
+ PR tree-optimization/92420
+ * tree-vect-stmts.c (get_negative_load_store_type): Move further
+ up file.
+ (get_group_load_store_type): Use it for reversed SLP accesses.
+
+2020-02-18 Richard Sandiford <richard.sandiford@arm.com>
+
+ Backport from mainline
2019-08-21 Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
PR target/90724
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 179c18d..3ec4cf5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-18 Richard Sandiford <richard.sandiford@arm.com>
+
+ PR tree-optimization/92420
+ * gcc.dg/vect/pr92420.c: New test.
+
2020-02-14 Hongtao Liu <hongtao.liu@intel.com>
* gcc.target/i386/avx512vbmi2-vpshld-1.c: New test.
diff --git a/gcc/testsuite/gcc.dg/vect/pr92420.c b/gcc/testsuite/gcc.dg/vect/pr92420.c
new file mode 100644
index 0000000..e43539f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr92420.c
@@ -0,0 +1,48 @@
+/* { dg-additional-options "-mavx2" { target avx_runtime } } */
+
+#include "tree-vect.h"
+
+#define N 16
+struct C { int r, i; };
+struct C a[N], b[N], c[N], d[N], e[N];
+
+__attribute__((noipa)) static void
+foo (struct C *__restrict x, struct C *__restrict y, struct C *__restrict z, int w)
+{
+ int i;
+ for (int i = 0; i < w; i++)
+ {
+ z[i].r = x[i].r * y[-1 - i].r - x[i].i * y[-1 - i].i;
+ z[i].i = x[i].i * y[-1 - i].r + x[i].r * y[-1 - i].i;
+ }
+}
+
+__attribute__((noipa)) static void
+bar (struct C *__restrict x, struct C *__restrict y, struct C *__restrict z, int w)
+{
+ int i;
+ for (int i = 0; i < w; i++)
+ {
+ z[i].r = x[i].r * y[i].r - x[i].i * y[i].i;
+ z[i].i = x[i].i * y[i].r + x[i].r * y[i].i;
+ }
+}
+
+int
+main ()
+{
+ check_vect ();
+ int i;
+ for (i = 0; i < N; ++i)
+ {
+ a[i].r = N - i; a[i].i = i - N;
+ b[i].r = i - N; b[i].i = i + N;
+ c[i].r = -1 - i; c[i].i = 2 * N - 1 - i;
+ }
+ foo (a, b + N, d, N);
+ bar (a, c, e, N);
+ for (i = 0; i < N; ++i)
+ if (d[i].r != e[i].r || d[i].i != e[i].i)
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index baabdb0..8fd7af1 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -2166,6 +2166,56 @@ perm_mask_for_reverse (tree vectype)
return vect_gen_perm_mask_checked (vectype, indices);
}
+/* A subroutine of get_load_store_type, with a subset of the same
+ arguments. Handle the case where STMT_INFO is a load or store that
+ accesses consecutive elements with a negative step. */
+
+static vect_memory_access_type
+get_negative_load_store_type (stmt_vec_info stmt_info, tree vectype,
+ vec_load_store_type vls_type,
+ unsigned int ncopies)
+{
+ dr_vec_info *dr_info = STMT_VINFO_DR_INFO (stmt_info);
+ dr_alignment_support alignment_support_scheme;
+
+ if (ncopies > 1)
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "multiple types with negative step.\n");
+ return VMAT_ELEMENTWISE;
+ }
+
+ alignment_support_scheme = vect_supportable_dr_alignment (dr_info, false);
+ if (alignment_support_scheme != dr_aligned
+ && alignment_support_scheme != dr_unaligned_supported)
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "negative step but alignment required.\n");
+ return VMAT_ELEMENTWISE;
+ }
+
+ if (vls_type == VLS_STORE_INVARIANT)
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_NOTE, vect_location,
+ "negative step with invariant source;"
+ " no permute needed.\n");
+ return VMAT_CONTIGUOUS_DOWN;
+ }
+
+ if (!perm_mask_for_reverse (vectype))
+ {
+ if (dump_enabled_p ())
+ dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+ "negative step and reversing not supported.\n");
+ return VMAT_ELEMENTWISE;
+ }
+
+ return VMAT_CONTIGUOUS_REVERSE;
+}
+
/* STMT_INFO is either a masked or unconditional store. Return the value
being stored. */
@@ -2268,7 +2318,15 @@ get_group_load_store_type (stmt_vec_info stmt_info, tree vectype, bool slp,
"Peeling for outer loop is not supported\n");
return false;
}
- *memory_access_type = VMAT_CONTIGUOUS;
+ int cmp = compare_step_with_zero (stmt_info);
+ if (cmp < 0)
+ *memory_access_type = get_negative_load_store_type
+ (stmt_info, vectype, vls_type, 1);
+ else
+ {
+ gcc_assert (!loop_vinfo || cmp > 0);
+ *memory_access_type = VMAT_CONTIGUOUS;
+ }
}
}
else
@@ -2370,56 +2428,6 @@ get_group_load_store_type (stmt_vec_info stmt_info, tree vectype, bool slp,
return true;
}
-/* A subroutine of get_load_store_type, with a subset of the same
- arguments. Handle the case where STMT_INFO is a load or store that
- accesses consecutive elements with a negative step. */
-
-static vect_memory_access_type
-get_negative_load_store_type (stmt_vec_info stmt_info, tree vectype,
- vec_load_store_type vls_type,
- unsigned int ncopies)
-{
- dr_vec_info *dr_info = STMT_VINFO_DR_INFO (stmt_info);
- dr_alignment_support alignment_support_scheme;
-
- if (ncopies > 1)
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "multiple types with negative step.\n");
- return VMAT_ELEMENTWISE;
- }
-
- alignment_support_scheme = vect_supportable_dr_alignment (dr_info, false);
- if (alignment_support_scheme != dr_aligned
- && alignment_support_scheme != dr_unaligned_supported)
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "negative step but alignment required.\n");
- return VMAT_ELEMENTWISE;
- }
-
- if (vls_type == VLS_STORE_INVARIANT)
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_NOTE, vect_location,
- "negative step with invariant source;"
- " no permute needed.\n");
- return VMAT_CONTIGUOUS_DOWN;
- }
-
- if (!perm_mask_for_reverse (vectype))
- {
- if (dump_enabled_p ())
- dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
- "negative step and reversing not supported.\n");
- return VMAT_ELEMENTWISE;
- }
-
- return VMAT_CONTIGUOUS_REVERSE;
-}
-
/* Analyze load or store statement STMT_INFO of type VLS_TYPE. Return true
if there is a memory access type that the vectorized form can use,
storing it in *MEMORY_ACCESS_TYPE if so. If we decide to use gathers
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