* [Committed] RISC-V: Disable BSWAP optimization for NUNITS < 4
@ 2023-11-24 5:04 Juzhe-Zhong
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From: Juzhe-Zhong @ 2023-11-24 5:04 UTC (permalink / raw)
To: gcc-patches; +Cc: Juzhe-Zhong
When fixing bugs, I notice there is a piece odd codes look incorrect.
which probably make codegen worse.
#include <stdint.h>
typedef int8_t vnx2qi __attribute__ ((vector_size (2)));
#define MASK_2(X, Y) (Y) - 1 - (X), (Y) - 2 - (X)
#define PERMUTE(TYPE, NUNITS) \
__attribute__ ((noipa)) void permute_##TYPE (TYPE values1, TYPE values2, \
TYPE *out) \
{ \
TYPE v \
= __builtin_shufflevector (values1, values2, MASK_##NUNITS (0, NUNITS)); \
*(TYPE *) out = v; \
}
#define TEST_ALL(T) \
T (vnx2qi, 2)
TEST_ALL (PERMUTE)
Before this patch:
vsetivli zero,2,e8,mf8,ta,ma
vle8.v v1,0(a0)
vsetivli zero,1,e16,mf4,ta,ma
vsrl.vi v2,v1,8
vsll.vi v1,v1,8
vor.vv v1,v2,v1
vsetivli zero,2,e8,mf8,ta,ma
vse8.v v1,0(a2)
ret
After this patch:
vsetivli zero,2,e8,mf8,ta,ma
vle8.v v3,0(a0)
vid.v v1
vrsub.vi v1,v1,1
vrgather.vv v2,v3,v1
vse8.v v2,0(a2)
ret
Committed as it is very obvious if during code review.
gcc/ChangeLog:
* config/riscv/riscv-v.cc (shuffle_bswap_pattern): Disable for NUNIT < 4.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c: Adapt test.
* gcc.target/riscv/rvv/autovec/vls/perm-4.c: Ditto.
---
gcc/config/riscv/riscv-v.cc | 5 +++++
.../gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c | 4 ++--
gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/perm-4.c | 4 ++--
3 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index 18619a11592..4bd1131ba87 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -3201,6 +3201,11 @@ shuffle_bswap_pattern (struct expand_vec_perm_d *d)
if (!d->perm.series_p (i, step, diff - i, step))
return false;
+ /* Disable when nunits < 4 since the later generic approach
+ is more profitable on BSWAP. */
+ if (!known_gt (GET_MODE_NUNITS (d->vmode), 2))
+ return false;
+
if (d->testing_p)
return true;
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c
index b235ec727b1..7ab31043547 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls-vlmax/perm-4.c
@@ -55,7 +55,7 @@
TEST_ALL (PERMUTE)
-/* { dg-final { scan-assembler-times {vrgather\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 18 } } */
+/* { dg-final { scan-assembler-times {vrgather\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 19 } } */
/* { dg-final { scan-assembler-times {vrgatherei16\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 12 } } */
-/* { dg-final { scan-assembler-times {vrsub\.vi} 23 } } */
+/* { dg-final { scan-assembler-times {vrsub\.vi} 24 } } */
/* { dg-final { scan-assembler-times {vrsub\.vx} 7 } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/perm-4.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/perm-4.c
index d2d49388a39..4d6862cf1c0 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/perm-4.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/vls/perm-4.c
@@ -3,7 +3,7 @@
#include "../vls-vlmax/perm-4.c"
-/* { dg-final { scan-assembler-times {vrgather\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 18 } } */
+/* { dg-final { scan-assembler-times {vrgather\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 19 } } */
/* { dg-final { scan-assembler-times {vrgatherei16\.vv\tv[0-9]+,\s*v[0-9]+,\s*v[0-9]+} 12 } } */
-/* { dg-final { scan-assembler-times {vrsub\.vi} 23 } } */
+/* { dg-final { scan-assembler-times {vrsub\.vi} 24 } } */
/* { dg-final { scan-assembler-times {vrsub\.vx} 7 } } */
--
2.36.3
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2023-11-24 5:04 [Committed] RISC-V: Disable BSWAP optimization for NUNITS < 4 Juzhe-Zhong
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