From: Richard Biener <rguenther@suse.de>
To: "juzhe.zhong@rivai.ai" <juzhe.zhong@rivai.ai>
Cc: Richard Biener <richard.guenther@gmail.com>,
gcc-patches <gcc-patches@gcc.gnu.org>,
"richard.sandiford" <richard.sandiford@arm.com>,
"kito.cheng" <kito.cheng@gmail.com>,
"Kito.cheng" <kito.cheng@sifive.com>
Subject: Re: Re: [PATCH] Middle-end: Fix bug of induction variable vectorization for RVV
Date: Fri, 10 Nov 2023 10:19:54 +0000 (UTC) [thread overview]
Message-ID: <nycvar.YFH.7.77.849.2311101018590.8772@jbgna.fhfr.qr> (raw)
In-Reply-To: <13B9AC74355D1006+2023111018134955379425@rivai.ai>
On Fri, 10 Nov 2023, juzhe.zhong@rivai.ai wrote:
> Hi, Richard.
>
> I am sorry for bothering you. I am trying to understand what you mean.
>
> Is this following codes that you want ?
>
> /* Create the vector that holds the step of the induction. */
> if (nested_in_vect_loop)
> {
> /* iv_loop is nested in the loop to be vectorized. Generate:
> vec_step = [S, S, S, S] */
> new_name = step_expr;
> /* We expect LOOP_VINFO_USING_SELECT_VL_P to be false in nested loop. */
> gcc_assert (!LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo));
> t = unshare_expr (new_name);
> gcc_assert (CONSTANT_CLASS_P (new_name)
> || TREE_CODE (new_name) == SSA_NAME);
> new_vec = build_vector_from_val (step_vectype, t);
> vec_step
> = vect_init_vector (loop_vinfo, stmt_info, new_vec, step_vectype, NULL);
> }
> else if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
> {
> /* When we're using loop_len produced by SELEC_VL, the non-final
> iterations are not always processing VF elements. So vectorize
> induction variable instead of
>
> _21 = vect_vec_iv_.6_22 + { VF, ... };
>
> We should generate:
>
> _35 = .SELECT_VL (ivtmp_33, VF);
> vect_cst__22 = [vec_duplicate_expr] _35;
> _21 = vect_vec_iv_.6_22 + vect_cst__22; */
> vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
> tree len = vect_get_loop_len (loop_vinfo, NULL, lens, 1, vectype, 0, 0);
> expr = force_gimple_operand (fold_convert (TREE_TYPE (step_expr),
> unshare_expr (len)),
> &seq, true, NULL_TREE);
> gsi_insert_seq_before (&si, seq, GSI_SAME_STMT);
> t = unshare_expr (new_name);
> gcc_assert (CONSTANT_CLASS_P (new_name)
> || TREE_CODE (new_name) == SSA_NAME);
> new_vec = build_vector_from_val (step_vectype, t);
> vec_step
> = vect_init_vector (loop_vinfo, stmt_info, new_vec, step_vectype, &si);
> }
> else
> {
> /* iv_loop is the loop to be vectorized. Generate:
> vec_step = [VF*S, VF*S, VF*S, VF*S] */
> gimple_seq seq = NULL;
> if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr)))
> {
> expr = build_int_cst (integer_type_node, vf);
> expr = gimple_build (&seq, FLOAT_EXPR, TREE_TYPE (step_expr), expr);
> }
> else
> expr = build_int_cst (TREE_TYPE (step_expr), vf);
> new_name = gimple_build (&seq, MULT_EXPR, TREE_TYPE (step_expr),
> expr, step_expr);
> if (seq)
> {
> new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
> gcc_assert (!new_bb);
> }
> t = unshare_expr (new_name);
> gcc_assert (CONSTANT_CLASS_P (new_name)
> || TREE_CODE (new_name) == SSA_NAME);
> new_vec = build_vector_from_val (step_vectype, t);
> vec_step
> = vect_init_vector (loop_vinfo, stmt_info, new_vec, step_vectype, NULL);
> }
>
> It seems that this following codes:
>
> t = unshare_expr (new_name);
> gcc_assert (CONSTANT_CLASS_P (new_name)
> || TREE_CODE (new_name) == SSA_NAME);
> new_vec = build_vector_from_val (step_vectype, t);
> vec_step
> = vect_init_vector
>
> appears 3 times. I am not sure whether it is the way you want?
I'd avoid that particular bit by having
gimple_stmt_iterator *si = NULL;
before the if () and set that accordingly only in the
LOOP_VINFO_USING_SELECT_VL_P path. But otherwise yes.
Richard.
>
> Thanks.
>
>
>
> juzhe.zhong@rivai.ai
>
> From: Richard Biener
> Date: 2023-11-10 17:46
> To: ???
> CC: richard.guenther; gcc-patches; richard.sandiford; kito.cheng; kito.cheng
> Subject: Re: Re: [PATCH] Middle-end: Fix bug of induction variable vectorization for RVV
> On Thu, 9 Nov 2023, ??? wrote:
>
> > Hi, Richard.
> >
> > >> I think it would be better to split out building a tree from VF from both
> > >> arms and avoid using 'vf' when LOOP_VINFO_USING_SELECT_VL_P.
> >
> > I am trying to split out building tree from both arms as you suggested..
> > Could you take a look the following codes ?
> >
> > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> > index 8abc1937d74..24a86187d11 100644
> > --- a/gcc/tree-vect-loop.cc
> > +++ b/gcc/tree-vect-loop.cc
> > @@ -10315,19 +10315,47 @@ vectorizable_induction (loop_vec_info loop_vinfo,
> > /* iv_loop is the loop to be vectorized. Generate:
> > vec_step = [VF*S, VF*S, VF*S, VF*S] */
> > gimple_seq seq = NULL;
> > - if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr)))
> > + if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
> > {
> > - expr = build_int_cst (integer_type_node, vf);
> > - expr = gimple_build (&seq, FLOAT_EXPR, TREE_TYPE (step_expr), expr);
> > + /* When we're using loop_len produced by SELEC_VL, the non-final
> > + iterations are not always processing VF elements. So vectorize
> > + induction variable instead of
> > +
> > + _21 = vect_vec_iv_.6_22 + { VF, ... };
> > +
> > + We should generate:
> > +
> > + _35 = .SELECT_VL (ivtmp_33, VF);
> > + vect_cst__22 = [vec_duplicate_expr] _35;
> > + _21 = vect_vec_iv_.6_22 + vect_cst__22; */
> > + vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
> > + tree len
> > + = vect_get_loop_len (loop_vinfo, NULL, lens, 1, vectype, 0, 0);
> > + expr = force_gimple_operand (fold_convert (TREE_TYPE (step_expr),
> > + unshare_expr (len)),
> > + &seq, true, NULL_TREE);
> > }
> > else
> > - expr = build_int_cst (TREE_TYPE (step_expr), vf);
> > + {
> > + bool float_p = SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr));
> > + expr = build_int_cst (float_p ? integer_type_node
> > + : TREE_TYPE (step_expr),
> > + vf);
> > + if (float_p)
> > + expr = gimple_build (&seq, FLOAT_EXPR, TREE_TYPE (step_expr), expr);
> > + }
> > +
>
> I meant you keep the existing flow in the function, specifically
> I think you should handle SCALAR_FLOAT_TYPE_P like it was previously
> handled, just build 'vf' in the dynamic way.
>
> > new_name = gimple_build (&seq, MULT_EXPR, TREE_TYPE (step_expr),
> > expr, step_expr);
> > if (seq)
> > {
> > - new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
> > - gcc_assert (!new_bb);
> > + if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
> > + gsi_insert_seq_before (&si, seq, GSI_SAME_STMT);
> > + else
> > + {
> > + new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
> > + gcc_assert (!new_bb);
> > + }
> > }
> > }
> >
> > @@ -10335,9 +10363,9 @@ vectorizable_induction (loop_vec_info loop_vinfo,
> > gcc_assert (CONSTANT_CLASS_P (new_name)
> > || TREE_CODE (new_name) == SSA_NAME);
> > new_vec = build_vector_from_val (step_vectype, t);
> > - vec_step = vect_init_vector (loop_vinfo, stmt_info,
> > - new_vec, step_vectype, NULL);
> > -
> > + vec_step
> > + = vect_init_vector (loop_vinfo, stmt_info, new_vec, step_vectype,
> > + LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo) ? &si : NULL);
>
> again this makes the flow hard to follow. I suppose refactoring this
> overall to
>
> if (nested_in_vect_loop)
> ...
> else if (LOOP_VINFO_USING_SELECT_VL_P (..))
> ...
> else
> ...
>
> and duplicate this tail into the cases makes it easier to follow.
>
> For nested_in_vect_loop we never have LOOP_VINFO_USING_SELECT_VL_P?
>
> Richard.
>
>
> > Thanks.
> >
> >
> > juzhe.zhong@rivai.ai
> >
> > From: Richard Biener
> > Date: 2023-11-09 20:16
> > To: Juzhe-Zhong
> > CC: gcc-patches; richard.sandiford; rguenther; kito.cheng; kito.cheng
> > Subject: Re: [PATCH] Middle-end: Fix bug of induction variable vectorization for RVV
> > On Wed, Nov 8, 2023 at 11:53?AM Juzhe-Zhong <juzhe.zhong@rivai.ai> wrote:
> > >
> > > PR: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112438
> > >
> > > SELECT_VL result is not necessary always VF in non-final iteration.
> > >
> > > Current GIMPLE IR is wrong:
> > >
> > > # vect_vec_iv_.21_25 = PHI <_24(4), { 0, 1, 2, ... }(3)>
> > > ...
> > > _24 = vect_vec_iv_.21_25 + { POLY_INT_CST [4, 4], ... };
> > >
> > > After this patch which is correct for SELECT_VL:
> > >
> > > # vect_vec_iv_.8_22 = PHI <_21(4), { 0, 1, 2, ... }(3)>
> > > ...
> > > _35 = .SELECT_VL (ivtmp_33, POLY_INT_CST [4, 4]);
> > > _21 = vect_vec_iv_.8_22 + { POLY_INT_CST [4, 4], ... };
> > >
> > > kito, could you give more explanation ?
> > >
> > > PR middle/112438
> > >
> > > gcc/ChangeLog:
> > >
> > > * tree-vect-loop.cc (vectorizable_induction): Fix bug.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > > * gcc.target/riscv/rvv/autovec/pr112438.c: New test.
> > >
> > > ---
> > > .../gcc.target/riscv/rvv/autovec/pr112438.c | 35 +++++++++++++++++
> > > gcc/tree-vect-loop.cc | 39 +++++++++++++++----
> > > 2 files changed, 67 insertions(+), 7 deletions(-)
> > > create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112438.c
> > >
> > > diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112438.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112438.c
> > > new file mode 100644
> > > index 00000000000..b326d56a52c
> > > --- /dev/null
> > > +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112438.c
> > > @@ -0,0 +1,35 @@
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-vect-cost-model -ffast-math -fdump-tree-optimized-details" } */
> > > +
> > > +void
> > > +foo (int n, int *__restrict in, int *__restrict out)
> > > +{
> > > + for (int i = 0; i < n; i += 1)
> > > + {
> > > + out[i] = in[i] + i;
> > > + }
> > > +}
> > > +
> > > +void
> > > +foo2 (int n, float * __restrict in,
> > > +float * __restrict out)
> > > +{
> > > + for (int i = 0; i < n; i += 1)
> > > + {
> > > + out[i] = in[i] + i;
> > > + }
> > > +}
> > > +
> > > +void
> > > +foo3 (int n, float * __restrict in,
> > > +float * __restrict out, float x)
> > > +{
> > > + for (int i = 0; i < n; i += 1)
> > > + {
> > > + out[i] = in[i] + i* i;
> > > + }
> > > +}
> > > +
> > > +/* We don't want to see vect_vec_iv_.21_25 + { POLY_INT_CST [4, 4], ... }. */
> > > +/* { dg-final { scan-tree-dump-not "\\+ \{ POLY_INT_CST" "optimized" } } */
> > > +
> > > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> > > index a544bc9b059..3e103946168 100644
> > > --- a/gcc/tree-vect-loop.cc
> > > +++ b/gcc/tree-vect-loop.cc
> > > @@ -10309,10 +10309,30 @@ vectorizable_induction (loop_vec_info loop_vinfo,
> > > new_name = step_expr;
> > > else
> > > {
> > > + gimple_seq seq = NULL;
> > > + if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
> > > + {
> > > + /* When we're using loop_len produced by SELEC_VL, the non-final
> > > + iterations are not always processing VF elements. So vectorize
> > > + induction variable instead of
> > > +
> > > + _21 = vect_vec_iv_.6_22 + { VF, ... };
> > > +
> > > + We should generate:
> > > +
> > > + _35 = .SELECT_VL (ivtmp_33, VF);
> > > + vect_cst__22 = [vec_duplicate_expr] _35;
> > > + _21 = vect_vec_iv_.6_22 + vect_cst__22; */
> > > + vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
> > > + tree len
> > > + = vect_get_loop_len (loop_vinfo, NULL, lens, 1, vectype, 0, 0);
> > > + expr = force_gimple_operand (fold_convert (TREE_TYPE (step_expr),
> > > + unshare_expr (len)),
> > > + &seq, true, NULL_TREE);
> > > + }
> >
> > I think it would be better to split out building a tree from VF from both
> > arms and avoid using 'vf' when LOOP_VINFO_USING_SELECT_VL_P.
> >
> > Btw, you are not patching the SLP path here which I believe has the same
> > problem but is currently exempt from non-constant VF at least.
> >
> > Richard.
> >
> > > /* iv_loop is the loop to be vectorized. Generate:
> > > vec_step = [VF*S, VF*S, VF*S, VF*S] */
> > > - gimple_seq seq = NULL;
> > > - if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr)))
> > > + else if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (step_expr)))
> > > {
> > > expr = build_int_cst (integer_type_node, vf);
> > > expr = gimple_build (&seq, FLOAT_EXPR, TREE_TYPE (step_expr), expr);
> > > @@ -10323,8 +10343,13 @@ vectorizable_induction (loop_vec_info loop_vinfo,
> > > expr, step_expr);
> > > if (seq)
> > > {
> > > - new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
> > > - gcc_assert (!new_bb);
> > > + if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
> > > + gsi_insert_seq_before (&si, seq, GSI_SAME_STMT);
> > > + else
> > > + {
> > > + new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
> > > + gcc_assert (!new_bb);
> > > + }
> > > }
> > > }
> > >
> > > @@ -10332,9 +10357,9 @@ vectorizable_induction (loop_vec_info loop_vinfo,
> > > gcc_assert (CONSTANT_CLASS_P (new_name)
> > > || TREE_CODE (new_name) == SSA_NAME);
> > > new_vec = build_vector_from_val (step_vectype, t);
> > > - vec_step = vect_init_vector (loop_vinfo, stmt_info,
> > > - new_vec, step_vectype, NULL);
> > > -
> > > + vec_step
> > > + = vect_init_vector (loop_vinfo, stmt_info, new_vec, step_vectype,
> > > + LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo) ? &si : NULL);
> > >
> > > /* Create the following def-use cycle:
> > > loop prolog:
> > > --
> > > 2.36.3
> > >
> >
> >
>
>
--
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
next prev parent reply other threads:[~2023-11-10 10:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-08 10:53 Juzhe-Zhong
2023-11-08 10:59 ` juzhe.zhong
2023-11-09 11:35 ` juzhe.zhong
2023-11-09 12:16 ` Richard Biener
2023-11-09 12:39 ` juzhe.zhong
2023-11-09 14:59 ` 钟居哲
2023-11-10 9:46 ` Richard Biener
2023-11-10 10:00 ` juzhe.zhong
2023-11-10 10:13 ` juzhe.zhong
2023-11-10 10:19 ` Richard Biener [this message]
2023-11-10 10:30 ` juzhe.zhong
2023-11-10 10:33 ` Richard Biener
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