diff mbox

move increase_alignment from simple to regular ipa pass

Message ID CAAgBjMkbX7qi0c1gdPGhZxD67bFBJcgh5dwUoMP-RH3n00cNZw@mail.gmail.com
State Superseded
Headers show

Commit Message

Prathamesh Kulkarni June 14, 2016, 1:01 p.m. UTC 
On 13 June 2016 at 16:13, Jan Hubicka <hubicka@ucw.cz> wrote:
>> diff --git a/gcc/cgraph.h b/gcc/cgraph.h

>> index ecafe63..41ac408 100644

>> --- a/gcc/cgraph.h

>> +++ b/gcc/cgraph.h

>> @@ -1874,6 +1874,9 @@ public:

>>       if we did not do any inter-procedural code movement.  */

>>    unsigned used_by_single_function : 1;

>>

>> +  /* Set if -fsection-anchors is set.  */

>> +  unsigned section_anchor : 1;

>> +

>>  private:

>>    /* Assemble thunks and aliases associated to varpool node.  */

>>    void assemble_aliases (void);

>> diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c

>> index 4bfcad7..e75d5c0 100644

>> --- a/gcc/cgraphunit.c

>> +++ b/gcc/cgraphunit.c

>> @@ -800,6 +800,9 @@ varpool_node::finalize_decl (tree decl)

>>       it is available to notice_global_symbol.  */

>>    node->definition = true;

>>    notice_global_symbol (decl);

>> +

>> +  node->section_anchor = flag_section_anchors;

>> +

>>    if (TREE_THIS_VOLATILE (decl) || DECL_PRESERVE_P (decl)

>>        /* Traditionally we do not eliminate static variables when not

>>        optimizing and when not doing toplevel reoder.  */

>> diff --git a/gcc/common.opt b/gcc/common.opt

>> index f0d7196..e497795 100644

>> --- a/gcc/common.opt

>> +++ b/gcc/common.opt

>> @@ -1590,6 +1590,10 @@ fira-algorithm=

>>  Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization

>>  -fira-algorithm=[CB|priority] Set the used IRA algorithm.

>>

>> +fipa-increase_alignment

>> +Common Report Var(flag_ipa_increase_alignment) Init(0) Optimization

>> +Option to gate increase_alignment ipa pass.

>> +

>>  Enum

>>  Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)

>>

>> @@ -2133,7 +2137,7 @@ Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization

>>  Enable the dependent count heuristic in the scheduler.

>>

>>  fsection-anchors

>> -Common Report Var(flag_section_anchors) Optimization

>> +Common Report Var(flag_section_anchors)

>>  Access data in the same section from shared anchor points.

>>

>>  fsee

>> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c

>> index a0db3a4..1482566 100644

>> --- a/gcc/config/aarch64/aarch64.c

>> +++ b/gcc/config/aarch64/aarch64.c

>> @@ -8252,6 +8252,8 @@ aarch64_override_options (void)

>>

>>    aarch64_register_fma_steering ();

>>

>> +  /* Enable increase_alignment pass.  */

>> +  flag_ipa_increase_alignment = 1;

>

> I would rather enable it always on targets that do support anchors.

AFAIK aarch64 supports section anchors.
>> diff --git a/gcc/lto/lto-symtab.c b/gcc/lto/lto-symtab.c

>> index ce9e146..7f09f3a 100644

>> --- a/gcc/lto/lto-symtab.c

>> +++ b/gcc/lto/lto-symtab.c

>> @@ -342,6 +342,13 @@ lto_symtab_merge (symtab_node *prevailing, symtab_node *entry)

>>       The type compatibility checks or the completing of types has properly

>>       dealt with most issues.  */

>>

>> +  /* ??? is this assert necessary ?  */

>> +  varpool_node *v_prevailing = dyn_cast<varpool_node *> (prevailing);

>> +  varpool_node *v_entry = dyn_cast<varpool_node *> (entry);

>> +  gcc_assert (v_prevailing && v_entry);

>> +  /* section_anchor of prevailing_decl wins.  */

>> +  v_entry->section_anchor = v_prevailing->section_anchor;

>> +

> Other flags are merged in lto_varpool_replace_node so please move this there.

Ah indeed, thanks for the pointers.
I wonder though if we need to set
prevailing_node->section_anchor = vnode->section_anchor ?
IIUC, the function merges flags from vnode into prevailing_node
and removes vnode. However we want prevailing_node->section_anchor
to always take precedence.
>> +/* Return true if alignment should be increased for this vnode.

>> +   This is done if every function that references/referring to vnode

>> +   has flag_tree_loop_vectorize set.  */

>> +

>> +static bool

>> +increase_alignment_p (varpool_node *vnode)

>> +{

>> +  ipa_ref *ref;

>> +

>> +  for (int i = 0; vnode->iterate_reference (i, ref); i++)

>> +    if (cgraph_node *cnode = dyn_cast<cgraph_node *> (ref->referred))

>> +      {

>> +     struct cl_optimization *opts = opts_for_fn (cnode->decl);

>> +     if (!opts->x_flag_tree_loop_vectorize)

>> +       return false;

>> +      }

>

> If you take address of function that has vectorizer enabled probably doesn't

> imply need to increase alignment of that var. So please drop the loop.

>

> You only want function that read/writes or takes address of the symbol. But

> onthe other hand, you need to walk all aliases of the symbol by

> call_for_symbol_and_aliases

>> +

>> +  for (int i = 0; vnode->iterate_referring (i, ref); i++)

>> +    if (cgraph_node *cnode = dyn_cast<cgraph_node *> (ref->referring))

>> +      {

>> +     struct cl_optimization *opts = opts_for_fn (cnode->decl);

>> +     if (!opts->x_flag_tree_loop_vectorize)

>> +       return false;

>> +      }

>> +

>> +  return true;

>> +}

>> +

>>  /* Entry point to increase_alignment pass.  */

>>  static unsigned int

>>  increase_alignment (void)

>> @@ -914,9 +942,12 @@ increase_alignment (void)

>>        tree decl = vnode->decl;

>>        unsigned int alignment;

>>

>> -      if ((decl_in_symtab_p (decl)

>> -       && !symtab_node::get (decl)->can_increase_alignment_p ())

>> -       || DECL_USER_ALIGN (decl) || DECL_ARTIFICIAL (decl))

>> +      if (!vnode->section_anchor

>> +       || (decl_in_symtab_p (decl)

>> +           && !symtab_node::get (decl)->can_increase_alignment_p ())

>> +       || DECL_USER_ALIGN (decl)

>> +       || DECL_ARTIFICIAL (decl)

>> +       || !increase_alignment_p (vnode))

>

> Incrementally we probably should do more testing whether the variable looks like

> someting that can be vectorized, i.e. it contains array, has address taken or the

> accesses are array accesses within loop.

> This can be done by the analysis phase of the IPA pass inspecting the function

> bodies.

Thanks, I will try to check for array accesses are within a loop in
followup patch.
I was wondering if we could we treat a homogeneous global struct
(having members of one type),
as a global array of that type and increase it's alignment if required ?
>

> I think it is important waste to bump up everything including error messages etc.

> At least on i386 the effect on firefox datasegment of various alignment setting is

> very visible.

Um for a start, would it be OK to check if all functions referencing variable
have attribute noreturn, and in that case we skip increasing the alignment ?
I suppose that error functions would be having attribute noreturn set ?
>

> Looks OK to me otherwise. please send updated patch.

I have done the changes in the attached patch (stage-1 built).
I am not sure what to return from the callback function and
arbitrarily chose to return true.

Thanks,
Prathamesh
>

> Honza
diff mbox

Patch

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index ecafe63..41ac408 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -1874,6 +1874,9 @@  public:
      if we did not do any inter-procedural code movement.  */
   unsigned used_by_single_function : 1;
 
+  /* Set if -fsection-anchors is set.  */
+  unsigned section_anchor : 1;
+
 private:
   /* Assemble thunks and aliases associated to varpool node.  */
   void assemble_aliases (void);
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 4bfcad7..e75d5c0 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -800,6 +800,9 @@  varpool_node::finalize_decl (tree decl)
      it is available to notice_global_symbol.  */
   node->definition = true;
   notice_global_symbol (decl);
+
+  node->section_anchor = flag_section_anchors;
+
   if (TREE_THIS_VOLATILE (decl) || DECL_PRESERVE_P (decl)
       /* Traditionally we do not eliminate static variables when not
 	 optimizing and when not doing toplevel reoder.  */
diff --git a/gcc/common.opt b/gcc/common.opt
index f0d7196..e497795 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1590,6 +1590,10 @@  fira-algorithm=
 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
 
+fipa-increase_alignment
+Common Report Var(flag_ipa_increase_alignment) Init(0) Optimization
+Option to gate increase_alignment ipa pass.
+
 Enum
 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
 
@@ -2133,7 +2137,7 @@  Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
 Enable the dependent count heuristic in the scheduler.
 
 fsection-anchors
-Common Report Var(flag_section_anchors) Optimization
+Common Report Var(flag_section_anchors)
 Access data in the same section from shared anchor points.
 
 fsee
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index a0db3a4..1482566 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -8252,6 +8252,8 @@  aarch64_override_options (void)
 
   aarch64_register_fma_steering ();
 
+  /* Enable increase_alignment pass.  */
+  flag_ipa_increase_alignment = 1;
 }
 
 /* Implement targetm.override_options_after_change.  */
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 3503c15..b7f448e 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3458,6 +3458,9 @@  arm_option_override (void)
 
   /* Init initial mode for testing.  */
   thumb_flipper = TARGET_THUMB;
+
+  /* Enable increase_alignment pass.  */
+  flag_ipa_increase_alignment = 1;
 }
 
 static void
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 2d7df6b..ed59068 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -5011,6 +5011,9 @@  rs6000_option_override (void)
     = { pass_analyze_swaps, "cse1", 1, PASS_POS_INSERT_BEFORE };
 
   register_pass (&analyze_swaps_info);
+
+  /* Enable increase_alignment pass.  */
+  flag_ipa_increase_alignment = 1;
 }
 
 
diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
index 5cef2ba..289d9c3 100644
--- a/gcc/lto-cgraph.c
+++ b/gcc/lto-cgraph.c
@@ -627,6 +627,7 @@  lto_output_varpool_node (struct lto_simple_output_block *ob, varpool_node *node,
   bp_pack_value (&bp, node->tls_model, 3);
   bp_pack_value (&bp, node->used_by_single_function, 1);
   bp_pack_value (&bp, node->need_bounds_init, 1);
+  bp_pack_value (&bp, node->section_anchor, 1);
   streamer_write_bitpack (&bp);
 
   group = node->get_comdat_group ();
@@ -1401,6 +1402,7 @@  input_varpool_node (struct lto_file_decl_data *file_data,
   node->tls_model = (enum tls_model)bp_unpack_value (&bp, 3);
   node->used_by_single_function = (enum tls_model)bp_unpack_value (&bp, 1);
   node->need_bounds_init = bp_unpack_value (&bp, 1);
+  node->section_anchor = bp_unpack_value (&bp, 1);
   group = read_identifier (ib);
   if (group)
     {
diff --git a/gcc/passes.def b/gcc/passes.def
index 3647e90..3a8063c 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -138,12 +138,12 @@  along with GCC; see the file COPYING3.  If not see
   PUSH_INSERT_PASSES_WITHIN (pass_ipa_tree_profile)
       NEXT_PASS (pass_feedback_split_functions);
   POP_INSERT_PASSES ()
-  NEXT_PASS (pass_ipa_increase_alignment);
   NEXT_PASS (pass_ipa_tm);
   NEXT_PASS (pass_ipa_lower_emutls);
   TERMINATE_PASS_LIST (all_small_ipa_passes)
 
   INSERT_PASSES_AFTER (all_regular_ipa_passes)
+  NEXT_PASS (pass_ipa_increase_alignment);
   NEXT_PASS (pass_ipa_whole_program_visibility);
   NEXT_PASS (pass_ipa_profile);
   NEXT_PASS (pass_ipa_icf);
diff --git a/gcc/testsuite/gcc.dg/vect/aligned-section-anchors-vect-73.c b/gcc/testsuite/gcc.dg/vect/aligned-section-anchors-vect-73.c
new file mode 100644
index 0000000..74eaed8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/aligned-section-anchors-vect-73.c
@@ -0,0 +1,25 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target section_anchors } */
+/* { dg-require-effective-target vect_int } */
+
+#define N 32
+
+/* Clone of section-anchors-vect-70.c with foo() having -fno-tree-loop-vectorize.  */ 
+
+static struct A {
+  int p1, p2;
+  int e[N];
+} a, b, c;
+
+__attribute__((optimize("-fno-tree-loop-vectorize")))
+int foo(void)
+{
+  for (int i = 0; i < N; i++)
+    a.e[i] = b.e[i] + c.e[i];
+
+   return a.e[0];
+}
+
+/* { dg-final { scan-ipa-dump-times "Increasing alignment of decl" 0 "increase_alignment" { target aarch64*-*-* } } } */
+/* { dg-final { scan-ipa-dump-times "Increasing alignment of decl" 0 "increase_alignment" { target powerpc64*-*-* } } } */
+/* { dg-final { scan-ipa-dump-times "Increasing alignment of decl" 0 "increase_alignment" { target arm*-*-* } } } */
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index 36299a6..d36aa1d 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -483,7 +483,7 @@  extern simple_ipa_opt_pass *make_pass_local_optimization_passes (gcc::context *c
 
 extern ipa_opt_pass_d *make_pass_ipa_whole_program_visibility (gcc::context
 							       *ctxt);
-extern simple_ipa_opt_pass *make_pass_ipa_increase_alignment (gcc::context
+extern ipa_opt_pass_d *make_pass_ipa_increase_alignment (gcc::context
 							      *ctxt);
 extern ipa_opt_pass_d *make_pass_ipa_inline (gcc::context *ctxt);
 extern simple_ipa_opt_pass *make_pass_ipa_free_lang_data (gcc::context *ctxt);
diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index 2669813..c693950 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -899,6 +899,55 @@  get_vec_alignment_for_type (tree type)
   return (alignment > TYPE_ALIGN (type)) ? alignment : 0;
 }
 
+/* Return true if alignment should be increased for this vnode.
+   This is done if every function that referring to vnode
+   has flag_tree_loop_vectorize set.  */ 
+
+static bool
+increase_alignment_p (varpool_node *vnode)
+{
+  ipa_ref *ref;
+  cgraph_node *cnode;
+
+  for (int i = 0; vnode->iterate_referring (i, ref); i++)
+    /* Walk those functions that read/write/take address of vnode.  */
+    if ((cnode = dyn_cast<cgraph_node *> (ref->referring))
+	&& (ref->use == IPA_REF_LOAD || ref->use == IPA_REF_STORE || ref->use == IPA_REF_ADDR))
+      {
+	struct cl_optimization *opts = opts_for_fn (cnode->decl);
+	if (!opts->x_flag_tree_loop_vectorize) 
+	  return false;
+      }
+
+  return true; 
+}
+
+static bool 
+increase_alignment_callback (varpool_node *vnode, void *data ATTRIBUTE_UNUSED)
+{
+  tree decl = vnode->decl;
+
+  if (!vnode->section_anchor
+      || (decl_in_symtab_p (decl)
+	  && !symtab_node::get (decl)->can_increase_alignment_p ())
+      || DECL_USER_ALIGN (decl)
+      || DECL_ARTIFICIAL (decl)
+      || !increase_alignment_p (vnode))
+    return true; 
+
+  unsigned alignment = get_vec_alignment_for_type (TREE_TYPE (decl));
+  if (alignment && vect_can_force_dr_alignment_p (decl, alignment))
+    {
+      vnode->increase_alignment (alignment);
+      dump_printf (MSG_NOTE, "Increasing alignment of decl: ");
+      dump_generic_expr (MSG_NOTE, TDF_SLIM, decl);
+      dump_printf (MSG_NOTE, "\n");
+      return true; 
+    }
+
+  return true;
+}
+
 /* Entry point to increase_alignment pass.  */
 static unsigned int
 increase_alignment (void)
@@ -910,24 +959,7 @@  increase_alignment (void)
 
   /* Increase the alignment of all global arrays for vectorization.  */
   FOR_EACH_DEFINED_VARIABLE (vnode)
-    {
-      tree decl = vnode->decl;
-      unsigned int alignment;
-
-      if ((decl_in_symtab_p (decl)
-	  && !symtab_node::get (decl)->can_increase_alignment_p ())
-	  || DECL_USER_ALIGN (decl) || DECL_ARTIFICIAL (decl))
-	continue;
-
-      alignment = get_vec_alignment_for_type (TREE_TYPE (decl));
-      if (alignment && vect_can_force_dr_alignment_p (decl, alignment))
-        {
-	  vnode->increase_alignment (alignment);
-          dump_printf (MSG_NOTE, "Increasing alignment of decl: ");
-          dump_generic_expr (MSG_NOTE, TDF_SLIM, decl);
-          dump_printf (MSG_NOTE, "\n");
-        }
-    }
+    vnode->call_for_symbol_and_aliases (increase_alignment_callback, NULL, true);
 
   delete type_align_map;
   return 0;
@@ -938,7 +970,7 @@  namespace {
 
 const pass_data pass_data_ipa_increase_alignment =
 {
-  SIMPLE_IPA_PASS, /* type */
+  IPA_PASS, /* type */
   "increase_alignment", /* name */
   OPTGROUP_LOOP | OPTGROUP_VEC, /* optinfo_flags */
   TV_IPA_OPT, /* tv_id */
@@ -949,17 +981,26 @@  const pass_data pass_data_ipa_increase_alignment =
   0, /* todo_flags_finish */
 };
 
-class pass_ipa_increase_alignment : public simple_ipa_opt_pass
+class pass_ipa_increase_alignment : public ipa_opt_pass_d
 {
 public:
   pass_ipa_increase_alignment (gcc::context *ctxt)
-    : simple_ipa_opt_pass (pass_data_ipa_increase_alignment, ctxt)
+    : ipa_opt_pass_d (pass_data_ipa_increase_alignment, ctxt,
+			   NULL, /* generate_summary  */
+			   NULL, /* write summary  */
+			   NULL, /* read summary  */
+			   NULL, /* write optimization summary  */
+			   NULL, /* read optimization summary  */
+			   NULL, /* stmt fixup  */
+			   0, /* function_transform_todo_flags_start  */
+			   NULL, /* transform function  */
+			   NULL )/* variable transform  */
   {}
 
   /* opt_pass methods: */
   virtual bool gate (function *)
     {
-      return flag_section_anchors && flag_tree_loop_vectorize;
+      return flag_ipa_increase_alignment != 0; 
     }
 
   virtual unsigned int execute (function *) { return increase_alignment (); }
@@ -968,7 +1009,7 @@  public:
 
 } // anon namespace
 
-simple_ipa_opt_pass *
+ipa_opt_pass_d *
 make_pass_ipa_increase_alignment (gcc::context *ctxt)
 {
   return new pass_ipa_increase_alignment (ctxt);