[PATCH 2/3]middle-end match.pd: simplify debug dump checks
Tamar Christina
Tamar.Christina@arm.com
Tue Apr 25 12:30:00 GMT 2023
> -----Original Message-----
> From: Richard Biener <richard.guenther@gmail.com>
> Sent: Tuesday, April 18, 2023 11:48 AM
> To: Tamar Christina <Tamar.Christina@arm.com>
> Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; rguenther@suse.de;
> jlaw@ventanamicro.com
> Subject: Re: [PATCH 2/3]middle-end match.pd: simplify debug dump checks
>
> On Tue, Apr 18, 2023 at 12:22 PM Tamar Christina via Gcc-patches <gcc-
> patches@gcc.gnu.org> wrote:
> >
> > Hi All,
> >
> > This is a small improvement in QoL codegen for match.pd to save time
> > not re-evaluating the condition for printing debug information in every
> function.
> >
> > There is a small but consistent runtime and compile time win here.
> > The runtime win comes from not having to do the condition over again,
> > and on Arm plaforms we now use the new test-and-branch support for
> > booleans to only have a single instruction here.
> >
> > Compile time win is gotten from not having to do all the string
> > parsing for the printf and having less string interning to do.
> >
> > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> >
> > Ok for master?
>
> Ugh, I don't like the new global very much. Can't we compute it in the toplevel
> entry and pass it down as parameter? Like passing down the actual dump FILE
> *?
So the dumpfile itself is currently also a global, I did try wiring this down, but the
problem here is that eventually at the very top level, I need to modify the gimple_simplify
calls because of the overloads being created by the output, which also need the parameter.
There things become interesting because this then conflicts with the definitions in gimple-fold
which would also need to take an additional argument and it breaks the public API.
Wiring the dbg value through all the generated and public function requires quite a lot of changes
so I'm not sure this is worth it in that case. Should I just drop it?
Thanks,
Tamar
>
> The file output in output_line_directive was because we originally had
> match.pd #includeing multiple match-*.pd files, we'd want to keep that
> supported I think. But since the line directives are commented and there's the
> same info available below, like
>
> /* #line 798 "/home/rguenther/src/gcc-13-branch/gcc/match.pd" */
> tree captures[2] ATTRIBUTE_UNUSED = { _p0, _p1 };
> if (UNLIKELY (dump_file && (dump_flags &
> TDF_FOLDING))) fprintf (dump_file, "Matching expression %s:%d, %s:%d\n",
> "match.pd", 798, __FILE__, __LINE__);
>
> there's probably no point in emitting them anymore (originally I emitted them
> non-commented but that didn't improve debugging much). We might want
> to emit more "proper" line directives for the natively copied parts of match.pd
> when code-generating c_expr parts, but that would be something separate.
>
> Can you split the patch into two things? A patch removing output of the
> commented line directives at the call sites is OK.
>
> Richard.
>
> > Thanks,
> > Tamar
> >
> > gcc/ChangeLog:
> >
> > PR bootstrap/84402
> > * dumpfile.h (dump_folding_p): New.
> > * dumpfile.cc (set_dump_file): Use it.
> > * generic-match-head.cc (dump_debug): New.
> > * gimple-match-head.cc (dump_debug): New.
> > * genmatch.cc (output_line_directive): Support outputting only line
> > because file is implied.
> > (dt_simplify::gen_1): Call debug_dump instead of printf.
> >
> > --- inline copy of patch --
> > diff --git a/gcc/dumpfile.h b/gcc/dumpfile.h index
> >
> 7d5eca899dcc98676a9ce7a7efff8e439854ff89..e7b595ddecdcca9983d958
> 4b8b24
> > 17ae1941c7d4 100644
> > --- a/gcc/dumpfile.h
> > +++ b/gcc/dumpfile.h
> > @@ -522,6 +522,7 @@ parse_dump_option (const char *, const char **);
> > extern FILE *dump_file; extern dump_flags_t dump_flags; extern const
> > char *dump_file_name;
> > +extern bool dump_folding_p;
> >
> > extern bool dumps_are_enabled;
> >
> > diff --git a/gcc/dumpfile.cc b/gcc/dumpfile.cc index
> >
> 51f68c8c6b40051ba3125c84298ee44ca52f5d17..f805aa73f3aa244d84714
> 9eec265
> > 05181ce4efe8 100644
> > --- a/gcc/dumpfile.cc
> > +++ b/gcc/dumpfile.cc
> > @@ -63,6 +63,7 @@ FILE *dump_file = NULL; const char *dump_file_name;
> > dump_flags_t dump_flags; bool dumps_are_enabled = false;
> > +bool dump_folding_p = false;
> >
> >
> > /* Set global "dump_file" to NEW_DUMP_FILE, refreshing the
> "dumps_are_enabled"
> > @@ -73,6 +74,7 @@ set_dump_file (FILE *new_dump_file) {
> > dumpfile_ensure_any_optinfo_are_flushed ();
> > dump_file = new_dump_file;
> > + dump_folding_p = dump_file && (dump_flags & TDF_FOLDING);
> > dump_context::get ().refresh_dumps_are_enabled (); }
> >
> > diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc
> > index
> >
> f011204c5be450663231bdece0596317b37f9f9b..16b8f9f3b61d3d5651a5
> a41a8c05
> > 52f50b55cc7c 100644
> > --- a/gcc/generic-match-head.cc
> > +++ b/gcc/generic-match-head.cc
> > @@ -102,3 +102,17 @@ optimize_successive_divisions_p (tree, tree) {
> > return false;
> > }
> > +
> > +/* Helper method for debug printing to reducing string parsing overhead.
> Keep
> > + in sync with version in gimple-match-head.cc. */
> > +
> > +static
> > +void dump_debug (bool simplify, int loc, const char *file, int
> > +lineno) {
> > + if (simplify)
> > + fprintf (dump_file, "Applying pattern %s:%d, %s:%d\n", "match.pd", loc,
> > + file, lineno);
> > + else
> > + fprintf (dump_file, "Matching expression %s:%d, %s:%d\n", "match.pd",
> loc,
> > + file, lineno);
> > +}
> > \ No newline at end of file
> > diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc index
> >
> 638606b2502f640e59527fc5a0b23fa3bedd0cee..bd7c6ff4a3fb89d456b022
> 42707f
> > d823b737f20d 100644
> > --- a/gcc/genmatch.cc
> > +++ b/gcc/genmatch.cc
> > @@ -185,7 +185,8 @@ fprintf_indent (FILE *f, unsigned int indent,
> > const char *format, ...)
> >
> > static void
> > output_line_directive (FILE *f, location_t location,
> > - bool dumpfile = false, bool fnargs = false)
> > + bool dumpfile = false, bool fnargs = false,
> > + bool loc_only = false)
> > {
> > const line_map_ordinary *map;
> > linemap_resolve_location (line_table, location,
> > LRK_SPELLING_LOCATION, &map); @@ -204,7 +205,9 @@
> output_line_directive (FILE *f, location_t location,
> > else
> > ++file;
> >
> > - if (fnargs)
> > + if (loc_only)
> > + fprintf (f, "%d", loc.line);
> > + else if (fnargs)
> > fprintf (f, "\"%s\", %d", file, loc.line);
> > else
> > fprintf (f, "%s:%d", file, loc.line); @@ -3431,14 +3434,11 @@
> > dt_simplify::gen_1 (FILE *f, int indent, bool gimple, operand *result)
> > needs_label = true;
> > }
> >
> > - fprintf_indent (f, indent, "if (UNLIKELY (dump_file && (dump_flags &
> TDF_FOLDING))) "
> > - "fprintf (dump_file, \"%s ",
> > - s->kind == simplify::SIMPLIFY
> > - ? "Applying pattern" : "Matching expression");
> > - fprintf (f, "%%s:%%d, %%s:%%d\\n\", ");
> > + fprintf_indent (f, indent, "if (UNLIKELY (dump_folding_p)) "
> > + "dump_debug (%s, ", s->kind == simplify::SIMPLIFY ? "true" :
> > + "false");
> > output_line_directive (f,
> > result ? result->location : s->match->location, true,
> > - true);
> > + true, true);
> > fprintf (f, ", __FILE__, __LINE__);\n");
> >
> > fprintf_indent (f, indent, "{\n");
> > diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc index
> >
> ec603f9d043c3924ea442bb49b5300a3573503cf..ae0c5c8a74fd9f1acdb616
> 014941
> > b11961e96c04 100644
> > --- a/gcc/gimple-match-head.cc
> > +++ b/gcc/gimple-match-head.cc
> > @@ -1412,3 +1412,17 @@ get_conditional_internal_fn (code_helper code,
> tree type)
> > auto cfn = combined_fn (code);
> > return get_conditional_internal_fn (associated_internal_fn (cfn,
> > type)); }
> > +
> > +/* Helper method for debug printing to reducing string parsing overhead.
> Keep
> > + in sync with version in generic-match-head.cc. */
> > +
> > +static
> > +void dump_debug (bool simplify, int loc, const char *file, int
> > +lineno) {
> > + if (simplify)
> > + fprintf (dump_file, "Applying pattern %s:%d, %s:%d\n", "match.pd", loc,
> > + file, lineno);
> > + else
> > + fprintf (dump_file, "Matching expression %s:%d, %s:%d\n", "match.pd",
> loc,
> > + file, lineno);
> > +}
> > \ No newline at end of file
> >
> >
> >
> >
> > --
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