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RFA: Define vect_perm for variable-length SVE
- From: Richard Sandiford <richard dot sandiford at arm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 23 Aug 2018 10:14:41 +0100
- Subject: RFA: Define vect_perm for variable-length SVE
Variable-length SVE now supports enough permutes to define vect_perm.
The change to vect_perm_supported is currently a no-op because the
function is only called with a count of 3.
Tested on aarch64-linux-gnu (with and without SVE), aarch64_be-elf
and x86_64-linux-gnu. OK for the vect_perm_supported change?
I think the rest is covered by the SVE maintainership.
Richard
2018-08-23 Richard Sandiford <richard.sandiford@arm.com>
gcc/testsuite/
* lib/target-supports.exp (vect_perm_supported): Only return
false for variable-length vectors if the permute size is not
a power of 2.
(check_effective_target_vect_perm)
(check_effective_target_vect_perm_byte)
(check_effective_target_vect_perm_short): Remove check for
variable-length vectors.
* gcc.dg/vect/slp-23.c: Add an XFAIL for variable-length SVE.
* gcc.dg/vect/slp-perm-10.c: Likewise.
* gcc.dg/vect/slp-perm-9.c: Add an XFAIL for variable-length vectors.
Index: gcc/testsuite/lib/target-supports.exp
===================================================================
--- gcc/testsuite/lib/target-supports.exp 2018-08-21 14:47:06.491178839 +0100
+++ gcc/testsuite/lib/target-supports.exp 2018-08-23 10:09:45.296442485 +0100
@@ -5758,8 +5758,7 @@ proc check_effective_target_vect_perm {
} else {
set et_vect_perm_saved($et_index) 0
if { [is-effective-target arm_neon]
- || ([istarget aarch64*-*-*]
- && ![check_effective_target_vect_variable_length])
+ || [istarget aarch64*-*-*]
|| [istarget powerpc*-*-*]
|| [istarget spu-*-*]
|| [istarget i?86-*-*] || [istarget x86_64-*-*]
@@ -5824,7 +5823,9 @@ proc check_effective_target_vect_perm {
proc vect_perm_supported { count element_bits } {
set vector_bits [lindex [available_vector_sizes] 0]
- if { $vector_bits <= 0 } {
+ # The number of vectors has to be a power of 2 when permuting
+ # variable-length vectors.
+ if { $vector_bits <= 0 && ($count & -$count) != $count } {
return 0
}
set vf [expr { $vector_bits / $element_bits }]
@@ -5864,8 +5865,7 @@ proc check_effective_target_vect_perm_by
if { ([is-effective-target arm_neon]
&& [is-effective-target arm_little_endian])
|| ([istarget aarch64*-*-*]
- && [is-effective-target aarch64_little_endian]
- && ![check_effective_target_vect_variable_length])
+ && [is-effective-target aarch64_little_endian])
|| [istarget powerpc*-*-*]
|| [istarget spu-*-*]
|| ([istarget mips-*.*]
@@ -5904,8 +5904,7 @@ proc check_effective_target_vect_perm_sh
if { ([is-effective-target arm_neon]
&& [is-effective-target arm_little_endian])
|| ([istarget aarch64*-*-*]
- && [is-effective-target aarch64_little_endian]
- && ![check_effective_target_vect_variable_length])
+ && [is-effective-target aarch64_little_endian])
|| [istarget powerpc*-*-*]
|| [istarget spu-*-*]
|| (([istarget i?86-*-*] || [istarget x86_64-*-*])
Index: gcc/testsuite/gcc.dg/vect/slp-23.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/slp-23.c 2018-05-02 08:37:48.985604715 +0100
+++ gcc/testsuite/gcc.dg/vect/slp-23.c 2018-08-23 10:09:45.296442485 +0100
@@ -107,8 +107,8 @@ int main (void)
/* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect" { target { vect_strided8 && { ! { vect_no_align} } } } } } */
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { ! { vect_strided8 || vect_no_align } } } } } */
-/* We fail to vectorize the second loop with variable-length SVE but
- fall back to 128-bit vectors, which does use SLP. */
/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { ! vect_perm } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target vect_perm } } } */
+/* SLP fails for the second loop with variable-length SVE because
+ the load size is greater than the minimum vector size. */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target vect_perm xfail { aarch64_sve && vect_variable_length } } } } */
Index: gcc/testsuite/gcc.dg/vect/slp-perm-10.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/slp-perm-10.c 2016-11-11 17:07:36.516798781 +0000
+++ gcc/testsuite/gcc.dg/vect/slp-perm-10.c 2018-08-23 10:09:45.296442485 +0100
@@ -50,4 +50,6 @@ int main ()
}
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target vect_perm } } } */
+/* SLP fails for variable-length SVE because the load size is greater
+ than the minimum vector size. */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target vect_perm xfail { aarch64_sve && vect_variable_length } } } } */
Index: gcc/testsuite/gcc.dg/vect/slp-perm-9.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/slp-perm-9.c 2018-05-02 08:37:49.013604450 +0100
+++ gcc/testsuite/gcc.dg/vect/slp-perm-9.c 2018-08-23 10:09:45.296442485 +0100
@@ -59,7 +59,9 @@ int main (int argc, const char* argv[])
/* { dg-final { scan-tree-dump-times "vectorized 0 loops" 2 "vect" { target { ! { vect_perm_short || vect_load_lanes } } } } } */
/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { vect_perm_short || vect_load_lanes } } } } */
-/* { dg-final { scan-tree-dump-times "permutation requires at least three vectors" 1 "vect" { target { vect_perm_short && { ! vect_perm3_short } } } } } */
+/* We don't try permutes with a group size of 3 for variable-length
+ vectors. */
+/* { dg-final { scan-tree-dump-times "permutation requires at least three vectors" 1 "vect" { target { vect_perm_short && { ! vect_perm3_short } } xfail vect_variable_length } } } */
/* { dg-final { scan-tree-dump-not "permutation requires at least three vectors" "vect" { target vect_perm3_short } } } */
/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target { { ! vect_perm3_short } || vect_load_lanes } } } } */
/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_short && { ! vect_load_lanes } } } } } */