On Mon, May 25, 2020 at 1:10 PM guojiufu <guoji...@linux.ibm.com> wrote:
>
> Currently option -funroll-loops controls both GIMPLE unroler and
> RTL unroller. It is not able to control GIMPLE cunroller and
> RTL unroller independently. This patch introducing different flags
> to control them seperately, and this also provide more freedom to
> tune one of them without affecting another.
>
> This patch introduces two undocumented flags: -fcomplete-unroll-loops
> for GIMPLE cunroll, and -frtl-unroll-loops for RTL unroller. And
> these two options are enabled by original -funroll-loops.
I don't like the new -fcomplete-unroll-loops name. It does not
match the implementation either (the gate functions of cunroll
and cunrolli only check optimize against 2/3), given it just
controls whether unrolling can grow code size.
> - SET_OPTION_IF_UNSET (opts, opts_set, flag_unroll_loops, value);
> + SET_OPTION_IF_UNSET (opts, opts_set, flag_complete_unroll_loops, value);
This is also not a no-op change.
Since a new flag is not needed to fix the regression please avoid
adding -fcomplete-unroll-loops.
For -frtl-unroll-loops you should be able to use
EnabledBy(funroll-loops)
and thus you can simplify option handling accordingly.
Thanks,
Richard.
> Bootstrap and regtest pass on powerpc64le, is this ok for trunk?
>
> Jiufu
>
> ChangeLog:
> 2020-05-25 Jiufu Guo <guoji...@cn.ibm.com>
>
> * common.opt: Add -frtl-unroll-loops and -fcomplete-unroll-loops.
> * opts.c (enable_fdo_optimizations): Replace flag_unroll_loops
> with flag_complete_unroll_loops.
> * toplev.c (process_options): set flag_rtl_unroll_loops and
> flag_complete_unroll_loops if not explicitly set by user.
> * tree-ssa-loop-ivcanon.c (pass_complete_unroll::execute): Replace
> flag_unroll_loops with flag_complete_unroll_loops.
> * loop-init.c (pass_loop2::gate): Replace flag_unroll_loops with
> flag_rtl_unroll_loops.
> (pass_rtl_unroll_loops::gate): Replace flag_unroll_loops with
> flag_rtl_unroll_loops.
> ---
> gcc/common.opt | 8 ++++++++
> gcc/loop-init.c | 6 +++---
> gcc/opts.c | 2 +-
> gcc/toplev.c | 6 ++++++
> gcc/tree-ssa-loop-ivcanon.c | 2 +-
> 5 files changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 4464049fc1f..3b5ab52bb9d 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2856,6 +2856,14 @@ funroll-all-loops
> Common Report Var(flag_unroll_all_loops) Optimization
> Perform loop unrolling for all loops.
>
> +frtl-unroll-loops
> +Common Undocumented Var(flag_rtl_unroll_loops) Init(2) Optimization
> +; Perform rtl loop unrolling when iteration count is known.
> +
> +fcomplete-unroll-loops
> +Common Undocumented Var(flag_complete_unroll_loops) Init(2) Optimization
> +; Perform GIMPLE loop complete unrolling.
> +
> ; Nonzero means that loop optimizer may assume that the induction variables
> ; that control loops do not overflow and that the loops with nontrivial
> ; exit condition are not infinite
> diff --git a/gcc/loop-init.c b/gcc/loop-init.c
> index 401e5282907..e955068f36c 100644
> --- a/gcc/loop-init.c
> +++ b/gcc/loop-init.c
> @@ -360,7 +360,7 @@ pass_loop2::gate (function *fun)
> if (optimize > 0
> && (flag_move_loop_invariants
> || flag_unswitch_loops
> - || flag_unroll_loops
> + || flag_rtl_unroll_loops
> || (flag_branch_on_count_reg && targetm.have_doloop_end ())
> || cfun->has_unroll))
> return true;
> @@ -560,7 +560,7 @@ public:
> /* opt_pass methods: */
> virtual bool gate (function *)
> {
> - return (flag_unroll_loops || flag_unroll_all_loops ||
> cfun->has_unroll);
> + return (flag_rtl_unroll_loops || flag_unroll_all_loops ||
> cfun->has_unroll);
> }
>
> virtual unsigned int execute (function *);
> @@ -576,7 +576,7 @@ pass_rtl_unroll_loops::execute (function *fun)
> if (dump_file)
> df_dump (dump_file);
>
> - if (flag_unroll_loops)
> + if (flag_rtl_unroll_loops)
> flags |= UAP_UNROLL;
> if (flag_unroll_all_loops)
> flags |= UAP_UNROLL_ALL;
> diff --git a/gcc/opts.c b/gcc/opts.c
> index ec3ca0720f9..64c35d8d7fc 100644
> --- a/gcc/opts.c
> +++ b/gcc/opts.c
> @@ -1702,7 +1702,7 @@ enable_fdo_optimizations (struct gcc_options *opts,
> {
> SET_OPTION_IF_UNSET (opts, opts_set, flag_branch_probabilities, value);
> SET_OPTION_IF_UNSET (opts, opts_set, flag_profile_values, value);
> - SET_OPTION_IF_UNSET (opts, opts_set, flag_unroll_loops, value);
> + SET_OPTION_IF_UNSET (opts, opts_set, flag_complete_unroll_loops, value);
> SET_OPTION_IF_UNSET (opts, opts_set, flag_peel_loops, value);
> SET_OPTION_IF_UNSET (opts, opts_set, flag_tracer, value);
> SET_OPTION_IF_UNSET (opts, opts_set, flag_value_profile_transformations,
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index 96316fbd23b..c2b94d33464 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -1474,6 +1474,12 @@ process_options (void)
> if (flag_unroll_all_loops)
> flag_unroll_loops = 1;
>
> + if (flag_rtl_unroll_loops == AUTODETECT_VALUE)
> + flag_rtl_unroll_loops = flag_unroll_loops;
> +
> + if (flag_complete_unroll_loops == AUTODETECT_VALUE)
> + flag_complete_unroll_loops = flag_unroll_loops;
> +
> /* web and rename-registers help when run after loop unrolling. */
> if (flag_web == AUTODETECT_VALUE)
> flag_web = flag_unroll_loops;
> diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c
> index 8ab6ab3330c..cd5df353df5 100644
> --- a/gcc/tree-ssa-loop-ivcanon.c
> +++ b/gcc/tree-ssa-loop-ivcanon.c
> @@ -1603,7 +1603,7 @@ pass_complete_unroll::execute (function *fun)
> re-peeling the same loop multiple times. */
> if (flag_peel_loops)
> peeled_loops = BITMAP_ALLOC (NULL);
> - unsigned int val = tree_unroll_loops_completely (flag_unroll_loops
> + unsigned int val = tree_unroll_loops_completely (flag_complete_unroll_loops
> || flag_peel_loops
> || optimize >= 3, true);
> if (peeled_loops)
> --
> 2.17.1
>
