Re: [Patch (preapproved)] Guard Copy Header pass on flag_tree_loop_vectorize

[James Greenhalgh <james dot greenhalgh at arm dot com>]

On Thu, Jul 27, 2017 at 03:21:01PM +0100, James Greenhalgh wrote:
> On Thu, Jul 27, 2017 at 02:26:03PM +0200, Richard Biener wrote:
> > On Thu, Jul 27, 2017 at 2:08 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> > > On Thu, Jul 27, 2017 at 01:54:21PM +0200, Richard Biener wrote:
> > >> --- gcc/common.opt      (revision 250619)
> > >> +++ gcc/common.opt      (working copy)
> > >>  ftree-vectorize
> > >> -Common Report Var(flag_tree_vectorize) Optimization
> > >> +Common Report Optimization
> > >>  Enable vectorization on trees.
> > >>
> > >>  ftree-vectorizer-verbose=
> > >>
> > >> which shows a few other uses of flag_tree_vectorize:
> > >>
> > >> int
> > >> omp_max_vf (void)
> > >> {
> > >>   if (!optimize
> > >>       || optimize_debug
> > >>       || !flag_tree_loop_optimize
> > >>       || (!flag_tree_loop_vectorize
> > >>           && (global_options_set.x_flag_tree_loop_vectorize
> > >>               || global_options_set.x_flag_tree_vectorize)))
> > >>     return 1;
> > >>
> > >> not sure what that was supposed to test.  Jakub?  Similar
> > >> use in expand_omp_simd.
> > >
> > > The intent is/was to check if the vectorizer pass will be invoked,
> > > otherwise it makes no sense to generate the arrays.
> > > So, for -O0/-Og or -fno-tree-loop-optimize, we know that the pass
> > > isn't even in the pipeline.
> > > And otherwise the intent was that we try to optimize, unless
> > > user asked explicitly -fno-tree-loop-vectorize or -fno-tree-vectorize
> > > not to optimize.  Because the vect pass is enabled if:
> > > flag_tree_loop_vectorize || fun->has_force_vectorize_loops
> > > but returning non-zero from omp_max_vf and the other omp spot means
> > > there will be cfun->has_force_vectorize_loops.
> >
> > I see.  So it would be good to try if adding EnabledBy(ftree-vectorize) to
> > ftree-loop-vectorize/ftree-slp-vectorize would add those to global_options_set
> > iff -ftree-vectorize is enabled (the opts.c hunk setting the flags is then
> > redundant as well I guess).
>
> This looks like it works.
>
> I'll prepare the patch and put it through a full bootstrap cycle.

That patch looks like this, and was bootstrapped and tested on
aarch64-none-linux-gnu with no issues. I've also checked that -ftree-vectorize
causes -ftree-loop-vectorize and -ftree-slp-vectorize to appear in the verbose
asm dump as enabled, and that -fprofile-use still correctly turns on
both of the options. Finally I've checked that -fprofile-use
-fno-tree-vectorize correctly results in neither of the options being
enabled.

OK?

Thanks,
James

---
2017-07-28  James Greenhalgh  <james.greenhalgh@arm.com>

	* common.opt (ftree-vectorize): No longer set flag_tree_vectorize.
	(ftree-loop-vectorize): Set as EnabledBy ftree-vectorize.
	(ftree-slp-vectorize): Likewise.
	* omp-expand (expand_omp_simd): Remove flag_tree_vectorize, as it
	can no longer be set independent of flag_tree_loop_vectorize.
	* omp-general.c (emp_max_vf): Likewise.
	* opts.c (enable_fdo_optimizations): Remove references to
	flag_tree_vectorize, these are now implicit.
	(common_handle_option): Remove handling for OPT_ftree_vectorize,
	and leave it for the options machinery.

diff --git a/gcc/common.opt b/gcc/common.opt
index 78cfa56..1cb1c83 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2691,8 +2691,9 @@ fvar-tracking-uninit
 Common Report Var(flag_var_tracking_uninit) PerFunction
 Perform variable tracking and also tag variables that are uninitialized.
 
+; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
 ftree-vectorize
-Common Report Var(flag_tree_vectorize) Optimization
+Common Report Optimization
 Enable vectorization on trees.
 
 ftree-vectorizer-verbose=
@@ -2700,11 +2701,11 @@ Common Joined RejectNegative Ignore
 Does nothing.  Preserved for backward compatibility.
 
 ftree-loop-vectorize
-Common Report Var(flag_tree_loop_vectorize) Optimization
+Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
 Enable loop vectorization on trees.
 
 ftree-slp-vectorize
-Common Report Var(flag_tree_slp_vectorize) Optimization
+Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
 Enable basic block vectorization (SLP) on trees.
 
 fvect-cost-model=
diff --git a/gcc/omp-expand.c b/gcc/omp-expand.c
index d6755cd..970e04f 100644
--- a/gcc/omp-expand.c
+++ b/gcc/omp-expand.c
@@ -4851,8 +4851,7 @@ expand_omp_simd (struct omp_region *region, struct omp_for_data *fd)
       /* If not -fno-tree-loop-vectorize, hint that we want to vectorize
 	 the loop.  */
       if ((flag_tree_loop_vectorize
-	   || (!global_options_set.x_flag_tree_loop_vectorize
-	       && !global_options_set.x_flag_tree_vectorize))
+	   || !global_options_set.x_flag_tree_loop_vectorize)
 	  && flag_tree_loop_optimize
 	  && loop->safelen > 1)
 	{
diff --git a/gcc/omp-general.c b/gcc/omp-general.c
index 9a5ed88..ed94668 100644
--- a/gcc/omp-general.c
+++ b/gcc/omp-general.c
@@ -429,8 +429,7 @@ omp_max_vf (void)
       || optimize_debug
       || !flag_tree_loop_optimize
       || (!flag_tree_loop_vectorize
-	  && (global_options_set.x_flag_tree_loop_vectorize
-	      || global_options_set.x_flag_tree_vectorize)))
+	  && global_options_set.x_flag_tree_loop_vectorize))
     return 1;
 
   int vf = 1;
diff --git a/gcc/opts.c b/gcc/opts.c
index 2f9a638..989cc6b 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1477,11 +1477,9 @@ enable_fdo_optimizations (struct gcc_options *opts,
     opts->x_flag_unswitch_loops = value;
   if (!opts_set->x_flag_gcse_after_reload)
     opts->x_flag_gcse_after_reload = value;
-  if (!opts_set->x_flag_tree_loop_vectorize
-      && !opts_set->x_flag_tree_vectorize)
+  if (!opts_set->x_flag_tree_loop_vectorize)
     opts->x_flag_tree_loop_vectorize = value;
-  if (!opts_set->x_flag_tree_slp_vectorize
-      && !opts_set->x_flag_tree_vectorize)
+  if (!opts_set->x_flag_tree_slp_vectorize)
     opts->x_flag_tree_slp_vectorize = value;
   if (!opts_set->x_flag_vect_cost_model)
     opts->x_flag_vect_cost_model = VECT_COST_MODEL_DYNAMIC;
@@ -2236,10 +2234,8 @@ common_handle_option (struct gcc_options *opts,
       break;
 
     case OPT_ftree_vectorize:
-      if (!opts_set->x_flag_tree_loop_vectorize)
-        opts->x_flag_tree_loop_vectorize = value;
-      if (!opts_set->x_flag_tree_slp_vectorize)
-        opts->x_flag_tree_slp_vectorize = value;
+      /* Automatically sets -ftree-loop-vectorize and
+	 -ftree-slp-vectorize.  Nothing more to do here.  */
       break;
     case OPT_fshow_column:
       dc->show_column = value;