[v3] RISC-V: Bugfix for RVV vbool*_t vn_reference_equal
Checks
Commit Message
From: Pan Li <pan2.li@intel.com>
In most architecture the precision_size of vbool*_t types are caculated
like as the multiple of the type size. For example:
precision_size = type_size * 8 (aka, bit count per bytes).
Unfortunately, some architecture like RISC-V will adjust the
precision_size
for the vbool*_t in order to align the ISA. For example as below.
type_size = [1, 1, 1, 1, 2, 4, 8]
precision_size = [1, 2, 4, 8, 16, 32, 64]
Then the precision_size of RISC-V vbool*_t will not be the multiple of
the
type_size. This PATCH try to enrich this case when comparing the
vn_reference.
Given we have the below code:
void test_vbool8_then_vbool16(int8_t * restrict in, int8_t * restrict
out) {
vbool8_t v1 = *(vbool8_t*)in;
vbool16_t v2 = *(vbool16_t*)in;
*(vbool8_t*)(out + 100) = v1;
*(vbool16_t*)(out + 200) = v2;
}
Before this PATCH:
csrr t0,vlenb
slli t1,t0,1
csrr a3,vlenb
sub sp,sp,t1
slli a4,a3,1
add a4,a4,sp
addi a2,a1,100
vsetvli a5,zero,e8,m1,ta,ma
sub a3,a4,a3
vlm.v v24,0(a0)
vsm.v v24,0(a2)
vsm.v v24,0(a3)
addi a1,a1,200
csrr t0,vlenb
vsetvli a4,zero,e8,mf2,ta,ma
slli t1,t0,1
vlm.v v24,0(a3)
vsm.v v24,0(a1)
add sp,sp,t1
jr ra
After this PATCH:
addi a3,a1,100
vsetvli a4,zero,e8,m1,ta,ma
addi a1,a1,200
vlm.v v24,0(a0)
vsm.v v24,0(a3)
vsetvli a5,zero,e8,mf2,ta,ma
vlm.v v24,0(a0)
vsm.v v24,0(a1)
ret
PR 109272
gcc/ChangeLog:
* tree-ssa-sccvn.cc (vn_reference_eq): add type vector subparts
check for vn_reference equal.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/base/pr108185-4.c: Update test check
condition.
* gcc.target/riscv/rvv/base/pr108185-5.c: Likewise.
* gcc.target/riscv/rvv/base/pr108185-6.c: Likewise.
Signed-off-by: Pan Li <pan2.li@intel.com>
---
.../gcc.target/riscv/rvv/base/pr108185-4.c | 2 +-
.../gcc.target/riscv/rvv/base/pr108185-5.c | 2 +-
.../gcc.target/riscv/rvv/base/pr108185-6.c | 2 +-
gcc/tree-ssa-sccvn.cc | 20 +++++++++++++++++++
4 files changed, 23 insertions(+), 3 deletions(-)
Comments
Committed, thanks!
On Tue, Apr 25, 2023 at 10:29 PM <pan2.li@intel.com> wrote:
> From: Pan Li <pan2.li@intel.com>
>
> In most architecture the precision_size of vbool*_t types are caculated
> like as the multiple of the type size. For example:
> precision_size = type_size * 8 (aka, bit count per bytes).
>
> Unfortunately, some architecture like RISC-V will adjust the
> precision_size
> for the vbool*_t in order to align the ISA. For example as below.
> type_size = [1, 1, 1, 1, 2, 4, 8]
> precision_size = [1, 2, 4, 8, 16, 32, 64]
>
> Then the precision_size of RISC-V vbool*_t will not be the multiple of
> the
> type_size. This PATCH try to enrich this case when comparing the
> vn_reference.
>
> Given we have the below code:
> void test_vbool8_then_vbool16(int8_t * restrict in, int8_t * restrict
> out) {
> vbool8_t v1 = *(vbool8_t*)in;
> vbool16_t v2 = *(vbool16_t*)in;
>
> *(vbool8_t*)(out + 100) = v1;
> *(vbool16_t*)(out + 200) = v2;
> }
>
> Before this PATCH:
> csrr t0,vlenb
> slli t1,t0,1
> csrr a3,vlenb
> sub sp,sp,t1
> slli a4,a3,1
> add a4,a4,sp
> addi a2,a1,100
> vsetvli a5,zero,e8,m1,ta,ma
> sub a3,a4,a3
> vlm.v v24,0(a0)
> vsm.v v24,0(a2)
> vsm.v v24,0(a3)
> addi a1,a1,200
> csrr t0,vlenb
> vsetvli a4,zero,e8,mf2,ta,ma
> slli t1,t0,1
> vlm.v v24,0(a3)
> vsm.v v24,0(a1)
> add sp,sp,t1
> jr ra
>
> After this PATCH:
> addi a3,a1,100
> vsetvli a4,zero,e8,m1,ta,ma
> addi a1,a1,200
> vlm.v v24,0(a0)
> vsm.v v24,0(a3)
> vsetvli a5,zero,e8,mf2,ta,ma
> vlm.v v24,0(a0)
> vsm.v v24,0(a1)
> ret
>
> PR 109272
>
> gcc/ChangeLog:
>
> * tree-ssa-sccvn.cc (vn_reference_eq): add type vector subparts
> check for vn_reference equal.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/riscv/rvv/base/pr108185-4.c: Update test check
> condition.
> * gcc.target/riscv/rvv/base/pr108185-5.c: Likewise.
> * gcc.target/riscv/rvv/base/pr108185-6.c: Likewise.
>
> Signed-off-by: Pan Li <pan2.li@intel.com>
> ---
> .../gcc.target/riscv/rvv/base/pr108185-4.c | 2 +-
> .../gcc.target/riscv/rvv/base/pr108185-5.c | 2 +-
> .../gcc.target/riscv/rvv/base/pr108185-6.c | 2 +-
> gcc/tree-ssa-sccvn.cc | 20 +++++++++++++++++++
> 4 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
> b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
> index 6e4d1cb1e44..321cd5c818e 100644
> --- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
> @@ -65,4 +65,4 @@ test_vbool8_then_vbool64(int8_t * restrict in, int8_t *
> restrict out) {
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> -/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 15 } } */
> +/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
> b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
> index 9fc659d2402..575a7842cdf 100644
> --- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
> @@ -65,4 +65,4 @@ test_vbool16_then_vbool64(int8_t * restrict in, int8_t *
> restrict out) {
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> -/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 14 } } */
> +/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
> b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
> index 98275e5267d..95a11d37016 100644
> --- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
> @@ -65,4 +65,4 @@ test_vbool32_then_vbool64(int8_t * restrict in, int8_t *
> restrict out) {
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf2,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
> /* { dg-final { scan-assembler-times
> {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> -/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 13 } } */
> +/* { dg-final { scan-assembler-times
> {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
> diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
> index 94b793e1caf..94d6163e6ae 100644
> --- a/gcc/tree-ssa-sccvn.cc
> +++ b/gcc/tree-ssa-sccvn.cc
> @@ -799,6 +799,26 @@ vn_reference_eq (const_vn_reference_t const vr1,
> const_vn_reference_t const vr2)
> && (TYPE_PRECISION (vr2->type)
> != TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
> return false;
> + else if (VECTOR_BOOLEAN_TYPE_P (vr1->type)
> + && VECTOR_BOOLEAN_TYPE_P (vr2->type))
> + {
> + /* Vector boolean types can have padding, verify we are dealing with
> + the same number of elements, aka the precision of the types.
> + For example, In most architecture the precision_size of vbool*_t
> + types are caculated like below:
> + precision_size = type_size * 8
> +
> + Unfortunately, the RISC-V will adjust the precision_size for the
> + vbool*_t in order to align the ISA as below:
> + type_size = [1, 1, 1, 1, 2, 4, 8]
> + precision_size = [1, 2, 4, 8, 16, 32, 64]
> +
> + Then the precision_size of RISC-V vbool*_t will not be the
> multiple
> + of the type_size. We take care of this case consolidated here.
> */
> + if (maybe_ne (TYPE_VECTOR_SUBPARTS (vr1->type),
> + TYPE_VECTOR_SUBPARTS (vr2->type)))
> + return false;
> + }
>
> i = 0;
> j = 0;
> --
> 2.34.1
>
>
Thanks a lot, kito, will pay more attention for the changelogs.
Pan
From: Kito Cheng <kito.cheng@sifive.com>
Sent: Wednesday, April 26, 2023 11:30 AM
To: Li, Pan2 <pan2.li@intel.com>
Cc: gcc-patches@gcc.gnu.org; juzhe.zhong@rivai.ai; Wang, Yanzhang <yanzhang.wang@intel.com>
Subject: Re: [PATCH v3] RISC-V: Bugfix for RVV vbool*_t vn_reference_equal
Committed, thanks!
On Tue, Apr 25, 2023 at 10:29 PM <pan2.li@intel.com<mailto:pan2.li@intel.com>> wrote:
From: Pan Li <pan2.li@intel.com<mailto:pan2.li@intel.com>>
In most architecture the precision_size of vbool*_t types are caculated
like as the multiple of the type size. For example:
precision_size = type_size * 8 (aka, bit count per bytes).
Unfortunately, some architecture like RISC-V will adjust the
precision_size
for the vbool*_t in order to align the ISA. For example as below.
type_size = [1, 1, 1, 1, 2, 4, 8]
precision_size = [1, 2, 4, 8, 16, 32, 64]
Then the precision_size of RISC-V vbool*_t will not be the multiple of
the
type_size. This PATCH try to enrich this case when comparing the
vn_reference.
Given we have the below code:
void test_vbool8_then_vbool16(int8_t * restrict in, int8_t * restrict
out) {
vbool8_t v1 = *(vbool8_t*)in;
vbool16_t v2 = *(vbool16_t*)in;
*(vbool8_t*)(out + 100) = v1;
*(vbool16_t*)(out + 200) = v2;
}
Before this PATCH:
csrr t0,vlenb
slli t1,t0,1
csrr a3,vlenb
sub sp,sp,t1
slli a4,a3,1
add a4,a4,sp
addi a2,a1,100
vsetvli a5,zero,e8,m1,ta,ma
sub a3,a4,a3
vlm.v v24,0(a0)
vsm.v v24,0(a2)
vsm.v v24,0(a3)
addi a1,a1,200
csrr t0,vlenb
vsetvli a4,zero,e8,mf2,ta,ma
slli t1,t0,1
vlm.v v24,0(a3)
vsm.v v24,0(a1)
add sp,sp,t1
jr ra
After this PATCH:
addi a3,a1,100
vsetvli a4,zero,e8,m1,ta,ma
addi a1,a1,200
vlm.v v24,0(a0)
vsm.v v24,0(a3)
vsetvli a5,zero,e8,mf2,ta,ma
vlm.v v24,0(a0)
vsm.v v24,0(a1)
ret
PR 109272
gcc/ChangeLog:
* tree-ssa-sccvn.cc (vn_reference_eq): add type vector subparts
check for vn_reference equal.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/base/pr108185-4.c: Update test check
condition.
* gcc.target/riscv/rvv/base/pr108185-5.c: Likewise.
* gcc.target/riscv/rvv/base/pr108185-6.c: Likewise.
Signed-off-by: Pan Li <pan2.li@intel.com<mailto:pan2.li@intel.com>>
---
.../gcc.target/riscv/rvv/base/pr108185-4.c | 2 +-
.../gcc.target/riscv/rvv/base/pr108185-5.c | 2 +-
.../gcc.target/riscv/rvv/base/pr108185-6.c | 2 +-
gcc/tree-ssa-sccvn.cc | 20 +++++++++++++++++++
4 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
index 6e4d1cb1e44..321cd5c818e 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-4.c
@@ -65,4 +65,4 @@ test_vbool8_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 15 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
index 9fc659d2402..575a7842cdf 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-5.c
@@ -65,4 +65,4 @@ test_vbool16_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 14 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
index 98275e5267d..95a11d37016 100644
--- a/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr108185-6.c
@@ -65,4 +65,4 @@ test_vbool32_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf2,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 13 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 94b793e1caf..94d6163e6ae 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -799,6 +799,26 @@ vn_reference_eq (const_vn_reference_t const vr1, const_vn_reference_t const vr2)
&& (TYPE_PRECISION (vr2->type)
!= TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
return false;
+ else if (VECTOR_BOOLEAN_TYPE_P (vr1->type)
+ && VECTOR_BOOLEAN_TYPE_P (vr2->type))
+ {
+ /* Vector boolean types can have padding, verify we are dealing with
+ the same number of elements, aka the precision of the types.
+ For example, In most architecture the precision_size of vbool*_t
+ types are caculated like below:
+ precision_size = type_size * 8
+
+ Unfortunately, the RISC-V will adjust the precision_size for the
+ vbool*_t in order to align the ISA as below:
+ type_size = [1, 1, 1, 1, 2, 4, 8]
+ precision_size = [1, 2, 4, 8, 16, 32, 64]
+
+ Then the precision_size of RISC-V vbool*_t will not be the multiple
+ of the type_size. We take care of this case consolidated here. */
+ if (maybe_ne (TYPE_VECTOR_SUBPARTS (vr1->type),
+ TYPE_VECTOR_SUBPARTS (vr2->type)))
+ return false;
+ }
i = 0;
j = 0;
--
2.34.1
@@ -65,4 +65,4 @@ test_vbool8_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 15 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
@@ -65,4 +65,4 @@ test_vbool16_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf4,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 14 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
@@ -65,4 +65,4 @@ test_vbool32_then_vbool64(int8_t * restrict in, int8_t * restrict out) {
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf2,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vsetvli\s+[a-x][0-9]+,\s*zero,\s*e8,\s*mf8,\s*ta,\s*ma} 1 } } */
/* { dg-final { scan-assembler-times {vlm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
-/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 13 } } */
+/* { dg-final { scan-assembler-times {vsm\.v\s+v[0-9]+,\s*0\([a-x][0-9]+\)} 12 } } */
@@ -799,6 +799,26 @@ vn_reference_eq (const_vn_reference_t const vr1, const_vn_reference_t const vr2)
&& (TYPE_PRECISION (vr2->type)
!= TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
return false;
+ else if (VECTOR_BOOLEAN_TYPE_P (vr1->type)
+ && VECTOR_BOOLEAN_TYPE_P (vr2->type))
+ {
+ /* Vector boolean types can have padding, verify we are dealing with
+ the same number of elements, aka the precision of the types.
+ For example, In most architecture the precision_size of vbool*_t
+ types are caculated like below:
+ precision_size = type_size * 8
+
+ Unfortunately, the RISC-V will adjust the precision_size for the
+ vbool*_t in order to align the ISA as below:
+ type_size = [1, 1, 1, 1, 2, 4, 8]
+ precision_size = [1, 2, 4, 8, 16, 32, 64]
+
+ Then the precision_size of RISC-V vbool*_t will not be the multiple
+ of the type_size. We take care of this case consolidated here. */
+ if (maybe_ne (TYPE_VECTOR_SUBPARTS (vr1->type),
+ TYPE_VECTOR_SUBPARTS (vr2->type)))
+ return false;
+ }
i = 0;
j = 0;