[PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Liška]

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Hello.

Building mariadb with -flto exposes a bug which I also used to see in Firefox. It's
caused by IPA CP starting from r236418, where the pass started to propagate const
VAR_DECLs. Problem is that the pass does not update call graph by adding IPA_REF_READ
of the propagated variable.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

Ready to be installed?
Martin

[-- Attachment #2: 0001-Fix-IPA-CP-where-it-forgot-to-add-a-reference-in-cgr.patch --]
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From 477e81fde08d0520ce552ec8baa0349590dc683c Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Mon, 19 Dec 2016 11:03:34 +0100
Subject: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

gcc/ChangeLog:

2016-12-19  Martin Liska  <mliska@suse.cz>

	* cgraphclones.c (cgraph_node::create_virtual_clone):
	Create either IPA_REF_LOAD of IPA_REF_READ depending on
	whether new_tree is a VAR_DECL or an ADDR_EXPR.
	* ipa-cp.c (create_specialized_node): Add reference just for
	ADDR_EXPRs.
	* symtab.c (symtab_node::maybe_create_reference): Remove guard
	as it's guarded in callers.
---
 gcc/cgraphclones.c | 6 +++++-
 gcc/ipa-cp.c       | 3 ++-
 gcc/symtab.c       | 2 --
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index 349892dab67..93c86e6a1cc 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -624,7 +624,11 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
       || in_lto_p)
     new_node->unique_name = true;
   FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
-    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
+    {
+      ipa_ref_use use_type
+	= TREE_CODE (map->new_tree) == VAR_DECL ? IPA_REF_ADDR : IPA_REF_LOAD;
+      new_node->maybe_create_reference (map->new_tree, use_type, NULL);
+    }
 
   if (ipa_transforms_to_apply.exists ())
     new_node->ipa_transforms_to_apply
diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index d3b50524457..fd312b56fde 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -3787,7 +3787,8 @@ create_specialized_node (struct cgraph_node *node,
 					 args_to_skip, "constprop");
   ipa_set_node_agg_value_chain (new_node, aggvals);
   for (av = aggvals; av; av = av->next)
-    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
+    if (TREE_CODE (av->value) == ADDR_EXPR)
+      new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/symtab.c b/gcc/symtab.c
index 73168a8db09..562a4a2f6a6 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -598,8 +598,6 @@ symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
 				     gimple *stmt)
 {
   STRIP_NOPS (val);
-  if (TREE_CODE (val) != ADDR_EXPR)
-    return NULL;
   val = get_base_var (val);
   if (val && VAR_OR_FUNCTION_DECL_P (val))
     {
-- 
2.11.0

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Jakub Jelinek]

Hi!

Just a nit, defer actual review to Honza or Richard.

On Mon, Dec 19, 2016 at 11:09:52AM +0100, Martin Liška wrote:
> +      ipa_ref_use use_type
> +	= TREE_CODE (map->new_tree) == VAR_DECL ? IPA_REF_ADDR : IPA_REF_LOAD;

	= VAR_P (map->new_tree) ? IPA_REF_ADDR : IPA_REF_LOAD.
please.

	Jakub

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Jambor]

Hi,

On Mon, Dec 19, 2016 at 11:09:52AM +0100, Martin Liska wrote:
> Hello.
> 
> Building mariadb with -flto exposes a bug which I also used to see
> in Firefox. It's caused by IPA CP starting from r236418, where the
> pass started to propagate const VAR_DECLs. Problem is that the pass
> does not update call graph by adding IPA_REF_READ of the propagated
> variable.
> 
> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
> 
> Ready to be installed?

Honza needs to have a look at this but since I have suggested this
approach, I am of course fine with it, except that...


> Martin

> From 477e81fde08d0520ce552ec8baa0349590dc683c Mon Sep 17 00:00:00 2001
> From: marxin <mliska@suse.cz>
> Date: Mon, 19 Dec 2016 11:03:34 +0100
> Subject: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph
> 
> gcc/ChangeLog:
> 
> 2016-12-19  Martin Liska  <mliska@suse.cz>
> 
> 	* cgraphclones.c (cgraph_node::create_virtual_clone):
> 	Create either IPA_REF_LOAD of IPA_REF_READ depending on
> 	whether new_tree is a VAR_DECL or an ADDR_EXPR.
> 	* ipa-cp.c (create_specialized_node): Add reference just for
> 	ADDR_EXPRs.
> 	* symtab.c (symtab_node::maybe_create_reference): Remove guard
> 	as it's guarded in callers.
> ---
>  gcc/cgraphclones.c | 6 +++++-
>  gcc/ipa-cp.c       | 3 ++-
>  gcc/symtab.c       | 2 --
>  3 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
> index 349892dab67..93c86e6a1cc 100644
> --- a/gcc/cgraphclones.c
> +++ b/gcc/cgraphclones.c
> @@ -624,7 +624,11 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
>        || in_lto_p)
>      new_node->unique_name = true;
>    FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
> -    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
> +    {
> +      ipa_ref_use use_type
> +	= TREE_CODE (map->new_tree) == VAR_DECL ? IPA_REF_ADDR : IPA_REF_LOAD;

...this test should be for ADDR_EXPR here.  Or you could switch the
IPA_REF_* constants the other way round which I bet is going to have
the same effect in practice, but personally, I'd test for ADDR_EXPR.

Thanks,

Martin

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Liška]

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On 12/20/2016 11:06 AM, Martin Jambor wrote:
> ...this test should be for ADDR_EXPR here.  Or you could switch the
> IPA_REF_* constants the other way round which I bet is going to have
> the same effect in practice, but personally, I'd test for ADDR_EXPR.

Thanks for the note, fixed (and tested in second version of the patch).

Martin

> 
> Thanks,
> 
> Martin


[-- Attachment #2: 0001-Fix-IPA-CP-where-it-forgot-to-add-a-reference-in-cgr-v2.patch --]
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From 2e29080e44cce899f9d5181185aba0a8a8791a9a Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Mon, 19 Dec 2016 11:03:34 +0100
Subject: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

gcc/ChangeLog:

2016-12-19  Martin Liska  <mliska@suse.cz>

	* cgraphclones.c (cgraph_node::create_virtual_clone):
	Create either IPA_REF_LOAD of IPA_REF_READ depending on
	whether new_tree is a VAR_DECL or an ADDR_EXPR.
	* ipa-cp.c (create_specialized_node): Add reference just for
	ADDR_EXPRs.
	* symtab.c (symtab_node::maybe_create_reference): Remove guard
	as it's guarded in callers.
---
 gcc/cgraphclones.c | 6 +++++-
 gcc/ipa-cp.c       | 3 ++-
 gcc/symtab.c       | 2 --
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index 349892dab67..6c8fe156f23 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -624,7 +624,11 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
       || in_lto_p)
     new_node->unique_name = true;
   FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
-    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
+    {
+      ipa_ref_use use_type
+	= TREE_CODE (map->new_tree) == ADDR_EXPR ? IPA_REF_ADDR : IPA_REF_LOAD;
+      new_node->maybe_create_reference (map->new_tree, use_type, NULL);
+    }
 
   if (ipa_transforms_to_apply.exists ())
     new_node->ipa_transforms_to_apply
diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index d3b50524457..fd312b56fde 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -3787,7 +3787,8 @@ create_specialized_node (struct cgraph_node *node,
 					 args_to_skip, "constprop");
   ipa_set_node_agg_value_chain (new_node, aggvals);
   for (av = aggvals; av; av = av->next)
-    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
+    if (TREE_CODE (av->value) == ADDR_EXPR)
+      new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/symtab.c b/gcc/symtab.c
index 73168a8db09..562a4a2f6a6 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -598,8 +598,6 @@ symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
 				     gimple *stmt)
 {
   STRIP_NOPS (val);
-  if (TREE_CODE (val) != ADDR_EXPR)
-    return NULL;
   val = get_base_var (val);
   if (val && VAR_OR_FUNCTION_DECL_P (val))
     {
-- 
2.11.0

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Liška]

PING^1

On 12/20/2016 03:55 PM, Martin Liška wrote:
> On 12/20/2016 11:06 AM, Martin Jambor wrote:
>> ...this test should be for ADDR_EXPR here.  Or you could switch the
>> IPA_REF_* constants the other way round which I bet is going to have
>> the same effect in practice, but personally, I'd test for ADDR_EXPR.
>
> Thanks for the note, fixed (and tested in second version of the patch).
>
> Martin
>
>>
>> Thanks,
>>
>> Martin
>

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Jan Hubicka]

> 
> 2016-12-19  Martin Liska  <mliska@suse.cz>
> 
> 	* cgraphclones.c (cgraph_node::create_virtual_clone):
> 	Create either IPA_REF_LOAD of IPA_REF_READ depending on
> 	whether new_tree is a VAR_DECL or an ADDR_EXPR.
> 	* ipa-cp.c (create_specialized_node): Add reference just for
> 	ADDR_EXPRs.
> 	* symtab.c (symtab_node::maybe_create_reference): Remove guard
> 	as it's guarded in callers.
> ---
>  gcc/cgraphclones.c | 6 +++++-
>  gcc/ipa-cp.c       | 3 ++-
>  gcc/symtab.c       | 2 --
>  3 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
> index 349892dab67..6c8fe156f23 100644
> --- a/gcc/cgraphclones.c
> +++ b/gcc/cgraphclones.c
> @@ -624,7 +624,11 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
>        || in_lto_p)
>      new_node->unique_name = true;
>    FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
> -    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
> +    {
> +      ipa_ref_use use_type
> +	= TREE_CODE (map->new_tree) == ADDR_EXPR ? IPA_REF_ADDR : IPA_REF_LOAD;
> +      new_node->maybe_create_reference (map->new_tree, use_type, NULL);
> +    }
>  
>    if (ipa_transforms_to_apply.exists ())
>      new_node->ipa_transforms_to_apply
> diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
> index d3b50524457..fd312b56fde 100644
> --- a/gcc/ipa-cp.c
> +++ b/gcc/ipa-cp.c
> @@ -3787,7 +3787,8 @@ create_specialized_node (struct cgraph_node *node,
>  					 args_to_skip, "constprop");
>    ipa_set_node_agg_value_chain (new_node, aggvals);
>    for (av = aggvals; av; av = av->next)
> -    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
> +    if (TREE_CODE (av->value) == ADDR_EXPR)
> +      new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
>  
>    if (dump_file && (dump_flags & TDF_DETAILS))
>      {
> diff --git a/gcc/symtab.c b/gcc/symtab.c
> index 73168a8db09..562a4a2f6a6 100644
> --- a/gcc/symtab.c
> +++ b/gcc/symtab.c
> @@ -598,8 +598,6 @@ symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
>  				     gimple *stmt)
>  {
>    STRIP_NOPS (val);
> -  if (TREE_CODE (val) != ADDR_EXPR)
> -    return NULL;

Perhaps maybe_create_reference should drop the use_type argument (it is used
with IPA_REF_ADDR only anyway) and should do the parsing itself?
I.e. if there is reference do IPA_REF_LOAD and if there is ADDR_EXPR do
IPA_REF_ADDR.  Why one can not have handled component refs in there?

Honza
>    val = get_base_var (val);
>    if (val && VAR_OR_FUNCTION_DECL_P (val))
>      {
> -- 
> 2.11.0
> 

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Liška]

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On 01/18/2017 11:18 PM, Jan Hubicka wrote:
>>
>> 2016-12-19  Martin Liska  <mliska@suse.cz>
>>
>> 	* cgraphclones.c (cgraph_node::create_virtual_clone):
>> 	Create either IPA_REF_LOAD of IPA_REF_READ depending on
>> 	whether new_tree is a VAR_DECL or an ADDR_EXPR.
>> 	* ipa-cp.c (create_specialized_node): Add reference just for
>> 	ADDR_EXPRs.
>> 	* symtab.c (symtab_node::maybe_create_reference): Remove guard
>> 	as it's guarded in callers.
>> ---
>>  gcc/cgraphclones.c | 6 +++++-
>>  gcc/ipa-cp.c       | 3 ++-
>>  gcc/symtab.c       | 2 --
>>  3 files changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
>> index 349892dab67..6c8fe156f23 100644
>> --- a/gcc/cgraphclones.c
>> +++ b/gcc/cgraphclones.c
>> @@ -624,7 +624,11 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
>>        || in_lto_p)
>>      new_node->unique_name = true;
>>    FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
>> -    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
>> +    {
>> +      ipa_ref_use use_type
>> +	= TREE_CODE (map->new_tree) == ADDR_EXPR ? IPA_REF_ADDR : IPA_REF_LOAD;
>> +      new_node->maybe_create_reference (map->new_tree, use_type, NULL);
>> +    }
>>  
>>    if (ipa_transforms_to_apply.exists ())
>>      new_node->ipa_transforms_to_apply
>> diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
>> index d3b50524457..fd312b56fde 100644
>> --- a/gcc/ipa-cp.c
>> +++ b/gcc/ipa-cp.c
>> @@ -3787,7 +3787,8 @@ create_specialized_node (struct cgraph_node *node,
>>  					 args_to_skip, "constprop");
>>    ipa_set_node_agg_value_chain (new_node, aggvals);
>>    for (av = aggvals; av; av = av->next)
>> -    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
>> +    if (TREE_CODE (av->value) == ADDR_EXPR)
>> +      new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
>>  
>>    if (dump_file && (dump_flags & TDF_DETAILS))
>>      {
>> diff --git a/gcc/symtab.c b/gcc/symtab.c
>> index 73168a8db09..562a4a2f6a6 100644
>> --- a/gcc/symtab.c
>> +++ b/gcc/symtab.c
>> @@ -598,8 +598,6 @@ symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
>>  				     gimple *stmt)
>>  {
>>    STRIP_NOPS (val);
>> -  if (TREE_CODE (val) != ADDR_EXPR)
>> -    return NULL;
> 
> Perhaps maybe_create_reference should drop the use_type argument (it is used
> with IPA_REF_ADDR only anyway) and should do the parsing itself?
> I.e. if there is reference do IPA_REF_LOAD and if there is ADDR_EXPR do
> IPA_REF_ADDR.  Why one can not have handled component refs in there?
> 
> Honza

Ok, this is updated version that I've been testing. Added a reference to PR that
we just identified that is also caused by IPA CP and will be fixed by the patch.

Thanks,
Martin

>>    val = get_base_var (val);
>>    if (val && VAR_OR_FUNCTION_DECL_P (val))
>>      {
>> -- 
>> 2.11.0
>>
> 


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From f42c5ea2ce09ecbf02e472ce31add53189115d66 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Mon, 19 Dec 2016 11:03:34 +0100
Subject: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph (PR
 ipa/71190).

gcc/ChangeLog:

2017-01-19  Martin Liska  <mliska@suse.cz>

	PR ipa/71190
	* cgraph.h (maybe_create_reference): Remove argument and
	update comment.
	* cgraphclones.c (cgraph_node::create_virtual_clone): Remove one
	argument.
	* ipa-cp.c (create_specialized_node): Likewise.
	* symtab.c (symtab_node::maybe_create_reference): Handle
	VAR_DECLs and ADDR_EXPRs and select ipa_ref_use type.
---
 gcc/cgraph.h       |  6 ++----
 gcc/cgraphclones.c |  2 +-
 gcc/ipa-cp.c       |  2 +-
 gcc/symtab.c       | 24 +++++++++++++++---------
 4 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index db2915c5751..5410a71176a 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -131,11 +131,9 @@ public:
 			     enum ipa_ref_use use_type, gimple *stmt);
 
   /* If VAL is a reference to a function or a variable, add a reference from
-     this symtab_node to the corresponding symbol table node.  USE_TYPE specify
-     type of the use and STMT the statement (if it exists).  Return the new
+     this symtab_node to the corresponding symbol table node.  Return the new
      reference or NULL if none was created.  */
-  ipa_ref *maybe_create_reference (tree val, enum ipa_ref_use use_type,
-				   gimple *stmt);
+  ipa_ref *maybe_create_reference (tree val, gimple *stmt);
 
   /* Clone all references from symtab NODE to this symtab_node.  */
   void clone_references (symtab_node *node);
diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index a17663519a9..c2337e84553 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -624,7 +624,7 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
       || in_lto_p)
     new_node->unique_name = true;
   FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
-    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
+    new_node->maybe_create_reference (map->new_tree, NULL);
 
   if (ipa_transforms_to_apply.exists ())
     new_node->ipa_transforms_to_apply
diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index 9cc903769e8..aa3c9973a66 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -3786,7 +3786,7 @@ create_specialized_node (struct cgraph_node *node,
 					 args_to_skip, "constprop");
   ipa_set_node_agg_value_chain (new_node, aggvals);
   for (av = aggvals; av; av = av->next)
-    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
+    new_node->maybe_create_reference (av->value, NULL);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/symtab.c b/gcc/symtab.c
index 87120970d34..64abf32ae13 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -588,18 +588,24 @@ symtab_node::create_reference (symtab_node *referred_node,
   return ref;
 }
 
-/* If VAL is a reference to a function or a variable, add a reference from
-   this symtab_node to the corresponding symbol table node.  USE_TYPE specify
-   type of the use and STMT the statement (if it exists).  Return the new
-   reference or NULL if none was created.  */
-
 ipa_ref *
-symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
-				     gimple *stmt)
+symtab_node::maybe_create_reference (tree val, gimple *stmt)
 {
   STRIP_NOPS (val);
-  if (TREE_CODE (val) != ADDR_EXPR)
-    return NULL;
+  ipa_ref_use use_type;
+
+  switch (TREE_CODE (val))
+    {
+    case VAR_DECL:
+      use_type = IPA_REF_LOAD;
+      break;
+    case ADDR_EXPR:
+      use_type = IPA_REF_ADDR;
+      break;
+    default:
+      return NULL;
+    }
+
   val = get_base_var (val);
   if (val && VAR_OR_FUNCTION_DECL_P (val))
     {
-- 
2.11.0

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Jan Hubicka]

> >> 2016-12-19  Martin Liska  <mliska@suse.cz>
> >>
> >> 	* cgraphclones.c (cgraph_node::create_virtual_clone):
> >> 	Create either IPA_REF_LOAD of IPA_REF_READ depending on
> >> 	whether new_tree is a VAR_DECL or an ADDR_EXPR.
> >> 	* ipa-cp.c (create_specialized_node): Add reference just for
> >> 	ADDR_EXPRs.
> >> 	* symtab.c (symtab_node::maybe_create_reference): Remove guard
> >> 	as it's guarded in callers.

Path is OK
>  ipa_ref *
> -symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
> -				     gimple *stmt)
> +symtab_node::maybe_create_reference (tree val, gimple *stmt)
>  {
>    STRIP_NOPS (val);
> -  if (TREE_CODE (val) != ADDR_EXPR)
> -    return NULL;
> +  ipa_ref_use use_type;
> +
> +  switch (TREE_CODE (val))
> +    {
> +    case VAR_DECL:
> +      use_type = IPA_REF_LOAD;
> +      break;
> +    case ADDR_EXPR:
> +      use_type = IPA_REF_ADDR;
> +      break;
> +    default:
> +      return NULL;
> +    }

I would add assert into default that we don't get handled_component_ref here so we are sure
we don't miss any declarations (because the bug leads to quite esoteric issues, it is better
to be safe than sorry)

Honza

Re: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph

[Martin Liška]

[-- Attachment #1: Type: text/plain, Size: 1329 bytes --]

On 01/19/2017 04:10 PM, Jan Hubicka wrote:
>>>> 2016-12-19  Martin Liska  <mliska@suse.cz>
>>>>
>>>> 	* cgraphclones.c (cgraph_node::create_virtual_clone):
>>>> 	Create either IPA_REF_LOAD of IPA_REF_READ depending on
>>>> 	whether new_tree is a VAR_DECL or an ADDR_EXPR.
>>>> 	* ipa-cp.c (create_specialized_node): Add reference just for
>>>> 	ADDR_EXPRs.
>>>> 	* symtab.c (symtab_node::maybe_create_reference): Remove guard
>>>> 	as it's guarded in callers.
> 
> Path is OK
>>  ipa_ref *
>> -symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
>> -				     gimple *stmt)
>> +symtab_node::maybe_create_reference (tree val, gimple *stmt)
>>  {
>>    STRIP_NOPS (val);
>> -  if (TREE_CODE (val) != ADDR_EXPR)
>> -    return NULL;
>> +  ipa_ref_use use_type;
>> +
>> +  switch (TREE_CODE (val))
>> +    {
>> +    case VAR_DECL:
>> +      use_type = IPA_REF_LOAD;
>> +      break;
>> +    case ADDR_EXPR:
>> +      use_type = IPA_REF_ADDR;
>> +      break;
>> +    default:
>> +      return NULL;
>> +    }
> 
> I would add assert into default that we don't get handled_component_ref here so we are sure
> we don't miss any declarations (because the bug leads to quite esoteric issues, it is better
> to be safe than sorry)
> 
> Honza
> 

Done in patch I've just installed as r244687.

Thanks for help,
Martin

[-- Attachment #2: 0001-Fix-IPA-CP-where-it-forgot-to-add-a-reference-in-cgr.patch --]
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From b0c002ba76312ba7cf38a41b1127ae8a55e89639 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Mon, 19 Dec 2016 11:03:34 +0100
Subject: [PATCH] Fix IPA CP where it forgot to add a reference in cgraph (PR
 ipa/71190).

gcc/ChangeLog:

2017-01-19  Martin Liska  <mliska@suse.cz>

	PR ipa/71190
	* cgraph.h (maybe_create_reference): Remove argument and
	update comment.
	* cgraphclones.c (cgraph_node::create_virtual_clone): Remove one
	argument.
	* ipa-cp.c (create_specialized_node): Likewise.
	* symtab.c (symtab_node::maybe_create_reference): Handle
	VAR_DECLs and ADDR_EXPRs and select ipa_ref_use type.
---
 gcc/cgraph.h       |  6 ++----
 gcc/cgraphclones.c |  2 +-
 gcc/ipa-cp.c       |  2 +-
 gcc/symtab.c       | 25 ++++++++++++++++---------
 4 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index db2915c5751..5410a71176a 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -131,11 +131,9 @@ public:
 			     enum ipa_ref_use use_type, gimple *stmt);
 
   /* If VAL is a reference to a function or a variable, add a reference from
-     this symtab_node to the corresponding symbol table node.  USE_TYPE specify
-     type of the use and STMT the statement (if it exists).  Return the new
+     this symtab_node to the corresponding symbol table node.  Return the new
      reference or NULL if none was created.  */
-  ipa_ref *maybe_create_reference (tree val, enum ipa_ref_use use_type,
-				   gimple *stmt);
+  ipa_ref *maybe_create_reference (tree val, gimple *stmt);
 
   /* Clone all references from symtab NODE to this symtab_node.  */
   void clone_references (symtab_node *node);
diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index a17663519a9..c2337e84553 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -624,7 +624,7 @@ cgraph_node::create_virtual_clone (vec<cgraph_edge *> redirect_callers,
       || in_lto_p)
     new_node->unique_name = true;
   FOR_EACH_VEC_SAFE_ELT (tree_map, i, map)
-    new_node->maybe_create_reference (map->new_tree, IPA_REF_ADDR, NULL);
+    new_node->maybe_create_reference (map->new_tree, NULL);
 
   if (ipa_transforms_to_apply.exists ())
     new_node->ipa_transforms_to_apply
diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c
index 9cc903769e8..aa3c9973a66 100644
--- a/gcc/ipa-cp.c
+++ b/gcc/ipa-cp.c
@@ -3786,7 +3786,7 @@ create_specialized_node (struct cgraph_node *node,
 					 args_to_skip, "constprop");
   ipa_set_node_agg_value_chain (new_node, aggvals);
   for (av = aggvals; av; av = av->next)
-    new_node->maybe_create_reference (av->value, IPA_REF_ADDR, NULL);
+    new_node->maybe_create_reference (av->value, NULL);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/symtab.c b/gcc/symtab.c
index 87120970d34..c21e7acf28c 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -588,18 +588,25 @@ symtab_node::create_reference (symtab_node *referred_node,
   return ref;
 }
 
-/* If VAL is a reference to a function or a variable, add a reference from
-   this symtab_node to the corresponding symbol table node.  USE_TYPE specify
-   type of the use and STMT the statement (if it exists).  Return the new
-   reference or NULL if none was created.  */
-
 ipa_ref *
-symtab_node::maybe_create_reference (tree val, enum ipa_ref_use use_type,
-				     gimple *stmt)
+symtab_node::maybe_create_reference (tree val, gimple *stmt)
 {
   STRIP_NOPS (val);
-  if (TREE_CODE (val) != ADDR_EXPR)
-    return NULL;
+  ipa_ref_use use_type;
+
+  switch (TREE_CODE (val))
+    {
+    case VAR_DECL:
+      use_type = IPA_REF_LOAD;
+      break;
+    case ADDR_EXPR:
+      use_type = IPA_REF_ADDR;
+      break;
+    default:
+      gcc_assert (!handled_component_p (val));
+      return NULL;
+    }
+
   val = get_base_var (val);
   if (val && VAR_OR_FUNCTION_DECL_P (val))
     {
-- 
2.11.0