> 2018-11-07 Martin Liska <mliska@xxxxxxx>
>
> * common.opt: Add -fipa-stack-alignment flag.
> * doc/invoke.texi: Document it.
> * final.c (rest_of_clean_state): Guard stack
> shrinking with flag.
OK
> gcc/ChangeLog:
>
> 2018-11-07 Martin Liska <mliska@xxxxxxx>
>
> * cgraph.h (ipa_discover_readonly_nonaddressable_vars): Rename
> to ...
> (ipa_discover_nonaddressable_vars): ... this.
> * common.opt: Come up with new flag -fipa-reference-addressable.
> * doc/invoke.texi: Document it.
> * ipa-reference.c (propagate): Call the renamed fn.
> * ipa-visibility.c (whole_program_function_and_variable_visibility):
> Likewise.
> * ipa.c (ipa_discover_readonly_nonaddressable_vars): Renamed to
> ...
> (ipa_discover_nonaddressable_vars): ... this. Discove
> non-addressable variables only with the newly added flag.
> * opts.c: Enable the newly added flag with -O1 and higher
> optimization level.
>
> gcc/testsuite/ChangeLog:
>
> 2018-11-07 Martin Liska <mliska@xxxxxxx>
>
> * gcc.dg/tree-ssa/writeonly-2.c: New test.
> ---
> gcc/cgraph.h | 2 +-
> gcc/common.opt | 6 +++++-
> gcc/doc/invoke.texi | 10 ++++++++--
> gcc/ipa-reference.c | 2 +-
> gcc/ipa-visibility.c | 2 +-
> gcc/ipa.c | 11 +++++++----
> gcc/opts.c | 1 +
> gcc/testsuite/gcc.dg/tree-ssa/writeonly-2.c | 20 ++++++++++++++++++++
> 8 files changed, 44 insertions(+), 10 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/writeonly-2.c
>
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index c13d79850fa..bf65d426cda 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -2403,7 +2403,7 @@ void record_references_in_initializer (tree, bool);
>
> /* In ipa.c */
> void cgraph_build_static_cdtor (char which, tree body, int priority);
> -bool ipa_discover_readonly_nonaddressable_vars (void);
> +bool ipa_discover_nonaddressable_vars (void);
I guess ipa_discover_variable_flags :)
>
> /* In varpool.c */
> tree ctor_for_folding (tree);
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 2971dc21b1f..6a64b0e27d5 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -1718,7 +1718,11 @@ Perform Identical Code Folding for variables.
>
> fipa-reference
> Common Report Var(flag_ipa_reference) Init(0) Optimization
> -Discover readonly and non addressable static variables.
> +Discover read-only and non addressable static variables.
> +
> +fipa-reference-addressable
> +Common Report Var(flag_ipa_reference_addressable) Init(0) Optimization
> +Discover read-only and write-only addressable variables.
I guess this should say
Discover read-only, write-only and non-addressable static variables
OK with that change.
Honza
>
> fipa-matrix-reorg
> Common Ignore
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index ae260c6ac6d..82c6fa913e8 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -412,8 +412,8 @@ Objective-C and Objective-C++ Dialects}.
> -finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol
> -finline-small-functions -fipa-cp -fipa-cp-clone @gol
> -fipa-bit-cp -fipa-vrp @gol
> --fipa-pta -fipa-profile -fipa-pure-const -fipa-reference -fipa-icf @gol
> --fira-algorithm=@var{algorithm} @gol
> +-fipa-pta -fipa-profile -fipa-pure-const -fipa-reference -fipa-reference-addressable @gol
> +-fipa-icf -fira-algorithm=@var{algorithm} @gol
> -fira-region=@var{region} -fira-hoist-pressure @gol
> -fira-loop-pressure -fno-ira-share-save-slots @gol
> -fno-ira-share-spill-slots @gol
> @@ -7866,6 +7866,7 @@ compilation time.
> -fipa-pure-const @gol
> -fipa-profile @gol
> -fipa-reference @gol
> +-fipa-reference-addressable @gol
> -fmerge-constants @gol
> -fmove-loop-invariants @gol
> -fomit-frame-pointer @gol
> @@ -8895,6 +8896,11 @@ Discover which static variables do not escape the
> compilation unit.
> Enabled by default at @option{-O} and higher.
>
> +@item -fipa-reference-addressable
> +@opindex fipa-reference-addressable
> +Discover read-only and write-only addressable variables.
> +Enabled by default at @option{-O} and higher.
> +
> @item -fipa-pta
> @opindex fipa-pta
> Perform interprocedural pointer analysis and interprocedural modification
> diff --git a/gcc/ipa-reference.c b/gcc/ipa-reference.c
> index 43bbdae5d66..2cdce3cbfa6 100644
> --- a/gcc/ipa-reference.c
> +++ b/gcc/ipa-reference.c
> @@ -705,7 +705,7 @@ propagate (void)
> if (dump_file)
> cgraph_node::dump_cgraph (dump_file);
>
> - remove_p = ipa_discover_readonly_nonaddressable_vars ();
> + remove_p = ipa_discover_nonaddressable_vars ();
> generate_summary ();
>
> /* Propagate the local information through the call graph to produce
> diff --git a/gcc/ipa-visibility.c b/gcc/ipa-visibility.c
> index 000207fa31b..1da594111f8 100644
> --- a/gcc/ipa-visibility.c
> +++ b/gcc/ipa-visibility.c
> @@ -911,7 +911,7 @@ whole_program_function_and_variable_visibility (void)
> {
> function_and_variable_visibility (flag_whole_program);
> if (optimize || in_lto_p)
> - ipa_discover_readonly_nonaddressable_vars ();
> + ipa_discover_nonaddressable_vars ();
> return 0;
> }
>
> diff --git a/gcc/ipa.c b/gcc/ipa.c
> index 3b6b5e5c8d4..eb53e7dcd06 100644
> --- a/gcc/ipa.c
> +++ b/gcc/ipa.c
> @@ -752,10 +752,10 @@ clear_addressable_bit (varpool_node *vnode, void *data ATTRIBUTE_UNUSED)
> return false;
> }
>
> -/* Discover variables that have no longer address taken or that are read only
> - and update their flags.
> +/* Discover variables that have no longer address taken, are read-only or
> + write-only and update their flags.
>
> - Return true when unreachable symbol removan should be done.
> + Return true when unreachable symbol removal should be done.
>
> FIXME: This can not be done in between gimplify and omp_expand since
> readonly flag plays role on what is shared and what is not. Currently we do
> @@ -764,8 +764,11 @@ clear_addressable_bit (varpool_node *vnode, void *data ATTRIBUTE_UNUSED)
> make sense to do it before early optimizations. */
>
> bool
> -ipa_discover_readonly_nonaddressable_vars (void)
> +ipa_discover_nonaddressable_vars (void)
> {
> + if (!flag_ipa_reference_addressable)
> + return false;
> +
> bool remove_p = false;
> varpool_node *vnode;
> if (dump_file)
> diff --git a/gcc/opts.c b/gcc/opts.c
> index 34c283dd765..9b9018c6c48 100644
> --- a/gcc/opts.c
> +++ b/gcc/opts.c
> @@ -451,6 +451,7 @@ static const struct default_options default_options_table[] =
> { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fif_conversion2, NULL, 1 },
> { OPT_LEVELS_1_PLUS, OPT_fipa_pure_const, NULL, 1 },
> { OPT_LEVELS_1_PLUS, OPT_fipa_reference, NULL, 1 },
> + { OPT_LEVELS_1_PLUS, OPT_fipa_reference_addressable, NULL, 1 },
> { OPT_LEVELS_1_PLUS, OPT_fipa_profile, NULL, 1 },
> { OPT_LEVELS_1_PLUS, OPT_fmerge_constants, NULL, 1 },
> { OPT_LEVELS_1_PLUS, OPT_freorder_blocks, NULL, 1 },
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/writeonly-2.c b/gcc/testsuite/gcc.dg/tree-ssa/writeonly-2.c
> new file mode 100644
> index 00000000000..2272d15b171
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/writeonly-2.c
> @@ -0,0 +1,20 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized -fno-ipa-reference-addressable" } */
> +static struct a {int magic1,b;} a;
> +volatile int magic2;
> +static struct b {int a,b,c,d,e,f;} magic3;
> +
> +struct b foo();
> +
> +void
> +t()
> +{
> + a.magic1 = 1;
> + magic2 = 1;
> + magic3 = foo();
> +}
> +/* { dg-final { scan-tree-dump "magic1" "optimized"} } */
> +/* { dg-final { scan-tree-dump "magic3" "optimized"} } */
> +/* { dg-final { scan-tree-dump "magic2" "optimized"} } */
> +/* { dg-final { scan-tree-dump "foo" "optimized"} } */
> +
> --
> 2.19.1
>
