On Fri, 3 Jul 2015, Richard Biener wrote:
> On Fri, 3 Jul 2015, Marek Polacek wrote:
>
> > This patch implements a new pass, called laddress, which deals with
> > lowering ADDR_EXPR assignments. Such lowering ought to help the
> > vectorizer, but it also could expose more CSE opportunities, maybe
> > help reassoc, etc. It's only active when optimize != 0.
> >
> > So e.g.
> > _1 = (sizetype) i_9;
> > _7 = _1 * 4;
> > _4 = &b + _7;
> > instead of
> > _4 = &b[i_9];
> >
> > This triggered 14105 times during the regtest and 6392 times during
> > the bootstrap.
> >
> > The fallout (at least on x86_64) is surprisingly small, i.e. none, just
> > gcc.dg/vect/pr59984.c test (using -fopenmp-simd) ICEs, but that is due
> > to a bug in the vectorizer. Jakub has a patch and knows the details.
> > As the test shows, we're now able to vectorize ADDR_EXPR of non-invariants
> > (that was the motivation of this pass).
> >
> > This doesn't introduce any kind of verification nor PROP_laddress.
> > Don't know if we want that, but hopefully it can be done as a follow-up
> > if we do.
>
> Yes. At the moment nothing requires lowered address form so this is
> merely an optimization (and not a bug for some later pass to
> re-introduce un-lowered non-invariant addresses). I can imagine
> that for example IVOPTs could be simplified if we didn't have this
> kind of addresses in the IL.
>
> > Do we want to move some optimizations into this new pass, e.g.
> > from fwprop?
>
> I think we might want to re-try forwprop_into_addr_expr before lowering
> the address. Well, but that's maybe just over-cautionous.
>
> > Thoughts?
>
> Please move the pass before crited, crited and pre are supposed to
> go together.
>
> Otherwise looks ok to me.
>
> Thanks,
> Richard.
>
> > Bootstrapped/regtested on x86_64-linux.
> >
> > 2015-07-03 Marek Polacek <pola...@redhat.com>
> >
> > PR tree-optimization/66718
> > * Makefile.in (OBJS): Add tree-ssa-laddress.o.
> > * passes.def: Schedule pass_laddress.
> > * timevar.def (DEFTIMEVAR): Add TV_TREE_LADDRESS.
> > * tree-pass.h (make_pass_laddress): Declare.
> > * tree-ssa-laddress.c: New file.
> >
> > * gcc.dg/vect/vect-126.c: New test.
> >
> > diff --git gcc/Makefile.in gcc/Makefile.in
> > index 89eda96..2574b98 100644
> > --- gcc/Makefile.in
> > +++ gcc/Makefile.in
> > @@ -1447,6 +1447,7 @@ OBJS = \
> > tree-ssa-dse.o \
> > tree-ssa-forwprop.o \
> > tree-ssa-ifcombine.o \
> > + tree-ssa-laddress.o \
I'd say gimple-laddress.c is a better fit. There is nothing
SSA specific in the pass and 'tree' is legacy...
> > tree-ssa-live.o \
> > tree-ssa-loop-ch.o \
> > tree-ssa-loop-im.o \
> > diff --git gcc/passes.def gcc/passes.def
> > index 0d8356b..ac16e8a 100644
> > --- gcc/passes.def
> > +++ gcc/passes.def
> > @@ -214,6 +214,7 @@ along with GCC; see the file COPYING3. If not see
> > NEXT_PASS (pass_cse_sincos);
> > NEXT_PASS (pass_optimize_bswap);
> > NEXT_PASS (pass_split_crit_edges);
> > + NEXT_PASS (pass_laddress);
> > NEXT_PASS (pass_pre);
> > NEXT_PASS (pass_sink_code);
> > NEXT_PASS (pass_asan);
> > diff --git gcc/testsuite/gcc.dg/vect/vect-126.c
> > gcc/testsuite/gcc.dg/vect/vect-126.c
> > index e69de29..66a5821 100644
> > --- gcc/testsuite/gcc.dg/vect/vect-126.c
> > +++ gcc/testsuite/gcc.dg/vect/vect-126.c
> > @@ -0,0 +1,64 @@
> > +/* PR tree-optimization/66718 */
> > +/* { dg-do compile } */
> > +/* { dg-additional-options "-mavx2" { target avx_runtime } } */
> > +
> > +int *a[1024], b[1024];
> > +struct S { int u, v, w, x; };
> > +struct S c[1024];
> > +int d[1024][10];
> > +
> > +void
> > +f0 (void)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + a[i] = &b[0];
> > +}
> > +
> > +void
> > +f1 (void)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + {
> > + int *p = &b[0];
> > + a[i] = p + i;
> > + }
> > +}
> > +
> > +void
> > +f2 (int *p)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + a[i] = &p[i];
> > +}
> > +
> > +void
> > +f3 (void)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + a[i] = &b[i];
> > +}
> > +
> > +void
> > +f4 (void)
> > +{
> > + int *p = &c[0].v;
> > + for (int i = 0; i < 1024; i++)
> > + a[i] = &p[4 * i];
> > +}
> > +
> > +void
> > +f5 (void)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + a[i] = &c[i].v;
> > +}
> > +
> > +void
> > +f6 (void)
> > +{
> > + for (int i = 0; i < 1024; i++)
> > + for (unsigned int j = 0; j < 10; j++)
> > + a[i] = &d[i][j];
> > +}
> > +
> > +/* { dg-final { scan-tree-dump-times "vectorized 1 loops in function" 7
> > "vect" { target vect_condition } } } */
> > diff --git gcc/timevar.def gcc/timevar.def
> > index efac4b7..fcc2fe0 100644
> > --- gcc/timevar.def
> > +++ gcc/timevar.def
> > @@ -275,6 +275,7 @@ DEFTIMEVAR (TV_GIMPLE_SLSR , "straight-line
> > strength reduction")
> > DEFTIMEVAR (TV_VTABLE_VERIFICATION , "vtable verification")
> > DEFTIMEVAR (TV_TREE_UBSAN , "tree ubsan")
> > DEFTIMEVAR (TV_INITIALIZE_RTL , "initialize rtl")
> > +DEFTIMEVAR (TV_TREE_LADDRESS , "address lowering")
> >
> > /* Everything else in rest_of_compilation not included above. */
> > DEFTIMEVAR (TV_EARLY_LOCAL , "early local passes")
> > diff --git gcc/tree-pass.h gcc/tree-pass.h
> > index 2808dad..c47b22e 100644
> > --- gcc/tree-pass.h
> > +++ gcc/tree-pass.h
> > @@ -393,6 +393,7 @@ extern gimple_opt_pass *make_pass_cd_dce (gcc::context
> > *ctxt);
> > extern gimple_opt_pass *make_pass_call_cdce (gcc::context *ctxt);
> > extern gimple_opt_pass *make_pass_merge_phi (gcc::context *ctxt);
> > extern gimple_opt_pass *make_pass_split_crit_edges (gcc::context *ctxt);
> > +extern gimple_opt_pass *make_pass_laddress (gcc::context *ctxt);
> > extern gimple_opt_pass *make_pass_pre (gcc::context *ctxt);
> > extern unsigned int tail_merge_optimize (unsigned int);
> > extern gimple_opt_pass *make_pass_profile (gcc::context *ctxt);
> > diff --git gcc/tree-ssa-laddress.c gcc/tree-ssa-laddress.c
> > index e69de29..3f69d7d 100644
> > --- gcc/tree-ssa-laddress.c
> > +++ gcc/tree-ssa-laddress.c
> > @@ -0,0 +1,137 @@
> > +/* Lower and optimize address expressions.
> > + Copyright (C) 2015 Free Software Foundation, Inc.
> > + Contributed by Marek Polacek <pola...@redhat.com>
> > +
> > +This file is part of GCC.
> > +
> > +GCC is free software; you can redistribute it and/or modify it under
> > +the terms of the GNU General Public License as published by the Free
> > +Software Foundation; either version 3, or (at your option) any later
> > +version.
> > +
> > +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> > +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> > +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> > +for more details.
> > +
> > +You should have received a copy of the GNU General Public License
> > +along with GCC; see the file COPYING3. If not see
> > +<http://www.gnu.org/licenses/>. */
> > +
> > +#include "config.h"
> > +#include "system.h"
> > +#include "coretypes.h"
> > +#include "alias.h"
> > +#include "predict.h"
> > +#include "tm.h"
> > +#include "function.h"
> > +#include "dominance.h"
> > +#include "cfg.h"
> > +#include "basic-block.h"
> > +#include "tree-ssa-alias.h"
> > +#include "symtab.h"
> > +#include "tree.h"
> > +#include "stringpool.h"
> > +#include "tree-ssanames.h"
> > +#include "fold-const.h"
> > +#include "gimple-expr.h"
> > +#include "gimple.h"
> > +#include "gimplify.h"
> > +#include "gimple-iterator.h"
> > +#include "gimplify-me.h"
> > +#include "tree-pass.h"
> > +
> > +
> > +namespace {
> > +
> > +const pass_data pass_data_laddress =
> > +{
> > + GIMPLE_PASS, /* type */
> > + "laddress", /* name */
> > + OPTGROUP_NONE, /* optinfo_flags */
> > + TV_TREE_LADDRESS, /* tv_id */
> > + ( PROP_cfg | PROP_ssa ), /* properties_required */
> > + 0, /* properties_provided */
> > + 0, /* properties_destroyed */
> > + 0, /* todo_flags_start */
> > + 0, /* todo_flags_finish */
> > +};
> > +
> > +class pass_laddress : public gimple_opt_pass
> > +{
> > +public:
> > + pass_laddress (gcc::context *ctxt)
> > + : gimple_opt_pass (pass_data_laddress, ctxt)
> > + {}
> > +
> > + /* opt_pass methods: */
> > + opt_pass * clone () { return new pass_laddress (m_ctxt); }
> > + virtual bool gate (function *) { return optimize != 0; }
> > + virtual unsigned int execute (function *);
> > +
> > +}; // class pass_laddress
> > +
> > +unsigned int
> > +pass_laddress::execute (function *fun)
> > +{
> > + basic_block bb;
> > +
> > + FOR_EACH_BB_FN (bb, fun)
> > + {
> > + for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
> > + {
> > + gimple stmt = gsi_stmt (gsi);
> > + if (!is_gimple_assign (stmt)
> > + || gimple_assign_rhs_code (stmt) != ADDR_EXPR
> > + || is_gimple_invariant_address (gimple_assign_rhs1 (stmt)))
> > + {
> > + gsi_next (&gsi);
> > + continue;
> > + }
> > +
> > + /* Lower ADDR_EXPR assignments:
> > + _4 = &b[i_9];
> > + into
> > + _1 = (sizetype) i_9;
> > + _7 = _1 * 4;
> > + _4 = &b + _7;
> > + This ought to aid the vectorizer and expose CSE opportunities.
> > + */
> > +
> > + tree expr = gimple_assign_rhs1 (stmt);
> > + HOST_WIDE_INT bitsize, bitpos;
> > + tree base, offset;
> > + machine_mode mode;
> > + int volatilep = 0, unsignedp = 0;
> > + base = get_inner_reference (TREE_OPERAND (expr, 0), &bitsize,
> > + &bitpos, &offset, &mode, &unsignedp,
> > + &volatilep, false);
> > + gcc_assert (base != NULL_TREE && (bitpos % BITS_PER_UNIT) == 0);
> > + if (offset != NULL_TREE)
> > + {
> > + if (bitpos != 0)
> > + offset = size_binop (PLUS_EXPR, offset,
> > + size_int (bitpos / BITS_PER_UNIT));
> > + offset = force_gimple_operand_gsi (&gsi, offset, true, NULL,
> > + true, GSI_SAME_STMT);
> > + base = build_fold_addr_expr (base);
> > + base = force_gimple_operand_gsi (&gsi, base, true, NULL,
> > + true, GSI_SAME_STMT);
> > + gimple g = gimple_build_assign (gimple_assign_lhs (stmt),
> > + POINTER_PLUS_EXPR, base, offset);
> > + gsi_replace (&gsi, g, false);
> > + }
> > + gsi_next (&gsi);
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +} // anon namespace
> > +
> > +gimple_opt_pass *
> > +make_pass_laddress (gcc::context *ctxt)
> > +{
> > + return new pass_laddress (ctxt);
> > +}
> >
> > Marek
> >
> >
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham
Norton, HRB 21284 (AG Nuernberg)
