diff mbox

[RFC,IPA-VRP] ADDR_EXPR and nonnull

Message ID c246f50d-2d3b-8a8e-82fd-ebf62207b991@linaro.org
State New
Headers show

Commit Message

Kugan Vivekanandarajah Oct. 21, 2016, 3:37 a.m. UTC
Hi,

On 20/10/16 23:15, Jan Hubicka wrote:
>> Hi Richard,

>>

>>

>> On 20/10/16 18:41, Richard Biener wrote:

>>> On Thu, 20 Oct 2016, kugan wrote:

>>>

>>>>

>>>>

>>>> On 20/10/16 01:26, Jan Hubicka wrote:

>>>>>>> Would excluding weak symbols (I believe I can check DECL_WEAK for this)

>>>>>>> good

>>>>>>> enough. Or looking for acceptable subset would work?

>>>>>>

>>>>>> I think we should add a symtab helper to tell if address_nonzero_p (if

>>>>>> that doesn't aleady exist).

>>>>>

>>>>> We have node->nonzero_address()

>>>>

>>>> Thanks for the pointer. Here is an attempt. Does this look OK?

>>>>

>>>> +	  if (TREE_CODE (arg) == ADDR_EXPR)

>>>> +	    {

>>>> +	      /* See if the AADR_EXPR is nonnull.  */

>>>> +	      varpool_node *node = NULL;

>>>> +	      tree base = TREE_OPERAND (arg, 0);

>>>> +	      base = get_base_address (base);

>>>> +

>>>> +	      if (decl_address_ip_invariant_p (base)

>>>> +		  || !is_global_var (base))

>>>> +		{

>>>> +		  /* If the symbol address is local or

>>>> +		     constant.  */

>>>

>>> "constant" doesn't matter.  You want

>>>

>>>   if (TREE_CODE (base) == CONST_DECL

>>> || TREE_CODE (base) == PARM_DECL

>>> || TREE_CODE (base) == RESULT_DECL)

>>>  addr_nonzero = true;

>>>   else if (VAR_P (base))

> Better to check decl_in_symtab_p (decl)

>>>     addr_nonzero = ! is_global_var (base) || (varpool_node::get

>>> (base)->nonzero_address ());

> and symtab_node::get.

>

> I wonder if we can't unify the logic with tree_expr_nonzero_warnv_p

> and corresponding vrp code?

Are you saying that we should export tree_expr_nonzero_warnv_p and use 
here with the logic from above added to tree_expr_nonzero_warnv_p as 
shown in the attached patch?

Thanks,
Kugan

>

> Otherwise the patch looks fine to me.

> Honza

>

Comments

Richard Biener Oct. 21, 2016, 7:16 a.m. UTC | #1
On Fri, 21 Oct 2016, kugan wrote:

> Hi,

> 

> On 20/10/16 23:15, Jan Hubicka wrote:

> > > Hi Richard,

> > > 

> > > 

> > > On 20/10/16 18:41, Richard Biener wrote:

> > > > On Thu, 20 Oct 2016, kugan wrote:

> > > > 

> > > > > 

> > > > > 

> > > > > On 20/10/16 01:26, Jan Hubicka wrote:

> > > > > > > > Would excluding weak symbols (I believe I can check DECL_WEAK

> > > > > > > > for this)

> > > > > > > > good

> > > > > > > > enough. Or looking for acceptable subset would work?

> > > > > > > 

> > > > > > > I think we should add a symtab helper to tell if address_nonzero_p

> > > > > > > (if

> > > > > > > that doesn't aleady exist).

> > > > > > 

> > > > > > We have node->nonzero_address()

> > > > > 

> > > > > Thanks for the pointer. Here is an attempt. Does this look OK?

> > > > > 

> > > > > +	  if (TREE_CODE (arg) == ADDR_EXPR)

> > > > > +	    {

> > > > > +	      /* See if the AADR_EXPR is nonnull.  */

> > > > > +	      varpool_node *node = NULL;

> > > > > +	      tree base = TREE_OPERAND (arg, 0);

> > > > > +	      base = get_base_address (base);

> > > > > +

> > > > > +	      if (decl_address_ip_invariant_p (base)

> > > > > +		  || !is_global_var (base))

> > > > > +		{

> > > > > +		  /* If the symbol address is local or

> > > > > +		     constant.  */

> > > > 

> > > > "constant" doesn't matter.  You want

> > > > 

> > > >   if (TREE_CODE (base) == CONST_DECL

> > > > || TREE_CODE (base) == PARM_DECL

> > > > || TREE_CODE (base) == RESULT_DECL)

> > > >  addr_nonzero = true;

> > > >   else if (VAR_P (base))

> > Better to check decl_in_symtab_p (decl)

> > > >     addr_nonzero = ! is_global_var (base) || (varpool_node::get

> > > > (base)->nonzero_address ());

> > and symtab_node::get.

> > 

> > I wonder if we can't unify the logic with tree_expr_nonzero_warnv_p

> > and corresponding vrp code?

> Are you saying that we should export tree_expr_nonzero_warnv_p and use here

> with the logic from above added to tree_expr_nonzero_warnv_p as shown in the

> attached patch?


tree_single_nonzero_warnv_p already handles this correctly via
maybe_nonzero_address.  And tree_single_nonzero_warnv_p is already
exported.

Richard.

> Thanks,

> Kugan

> 

> > 

> > Otherwise the patch looks fine to me.

> > Honza

> > 

> 


-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
diff mbox

Patch

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 89ed89d..6fa42c9 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -8954,7 +8954,7 @@  mask_with_tz (tree type, const wide_int &x, const wide_int &y)
    is undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't
    change *STRICT_OVERFLOW_P.  */
 
-static bool
+bool
 tree_expr_nonzero_warnv_p (tree t, bool *strict_overflow_p)
 {
   tree type = TREE_TYPE (t);
@@ -13402,9 +13402,15 @@  tree_single_nonzero_warnv_p (tree t, bool *strict_overflow_p)
 	  return true;
 
 	/* Constants are never weak.  */
-	if (CONSTANT_CLASS_P (base))
+	if (CONSTANT_CLASS_P (base)
+	    || TREE_CODE (base) == PARM_DECL
+	    || TREE_CODE (base) == RESULT_DECL)
 	  return true;
 
+	if (VAR_P (base)
+	    && (!is_global_var (base)
+		|| varpool_node::get (base)->nonzero_address ()))
+	  return true;
 	return false;
       }
 
diff --git a/gcc/fold-const.h b/gcc/fold-const.h
index bc22c88..a19a27a 100644
--- a/gcc/fold-const.h
+++ b/gcc/fold-const.h
@@ -198,6 +198,7 @@  extern tree fold_build_pointer_plus_loc (location_t loc, tree ptr, tree off);
 
 /* Build and fold a POINTER_PLUS_EXPR at LOC offsetting PTR by OFF.  */
 extern tree fold_build_pointer_plus_hwi_loc (location_t loc, tree ptr, HOST_WIDE_INT off);
+extern bool tree_expr_nonzero_warnv_p (tree t, bool *strict_overflow_p);
 
 #define fold_build_pointer_plus_hwi(p,o) \
 	fold_build_pointer_plus_hwi_loc (UNKNOWN_LOCATION, p, o)
diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
index 353b638..55a2ea1 100644
--- a/gcc/ipa-prop.c
+++ b/gcc/ipa-prop.c
@@ -1670,9 +1670,20 @@  ipa_compute_jump_functions_for_edge (struct ipa_func_body_info *fbi,
 
       if (POINTER_TYPE_P (TREE_TYPE (arg)))
 	{
+	  bool addr_nonzero = false;
+	  bool strict_overflow = false;
+
 	  if (TREE_CODE (arg) == SSA_NAME
 	      && param_type
 	      && get_ptr_nonnull (arg))
+	    addr_nonzero = true;
+	  else if (tree_expr_nonzero_warnv_p (arg, &strict_overflow))
+	    {
+	      if (!strict_overflow)
+		addr_nonzero = true;
+	    }
+
+	  if (addr_nonzero)
 	    {
 	      jfunc->vr_known = true;
 	      jfunc->m_vr.type = VR_ANTI_RANGE;
diff --git a/gcc/testsuite/gcc.dg/ipa/vrp5.c b/gcc/testsuite/gcc.dg/ipa/vrp5.c
index e69de29..571798d 100644
--- a/gcc/testsuite/gcc.dg/ipa/vrp5.c
+++ b/gcc/testsuite/gcc.dg/ipa/vrp5.c
@@ -0,0 +1,34 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-ipa-cp-details -fdump-tree-vrp1" } */
+
+static __attribute__((noinline, noclone))
+int foo (int *p)
+{
+  if (!p)
+    return 0;
+  *p = 1;
+}
+
+struct st
+{
+  int a;
+  int b;
+};
+
+int arr1[10];
+int a;
+int bar (struct st *s)
+{
+  int arr2[10];
+  int b;
+  if (!s)
+    return 0;
+  foo (&s->a);
+  foo (&a);
+  foo (&b);
+  foo (&arr1[1]);
+  foo (&arr2[1]);
+}
+
+/* { dg-final { scan-ipa-dump "Setting nonnull for 0" "cp" } } */
+/* { dg-final { scan-tree-dump-times "if" 1 "vrp1" } } */
diff --git a/gcc/testsuite/gcc.dg/ipa/vrp6.c b/gcc/testsuite/gcc.dg/ipa/vrp6.c
index e69de29..971db44 100644
--- a/gcc/testsuite/gcc.dg/ipa/vrp6.c
+++ b/gcc/testsuite/gcc.dg/ipa/vrp6.c
@@ -0,0 +1,34 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-ipa-cp-details -fdump-tree-vrp1" } */
+
+static __attribute__((noinline, noclone))
+int foo (int *p)
+{
+  if (!p)
+    return 0;
+  *p = 1;
+}
+
+struct st
+{
+  int a;
+  int b;
+};
+
+struct st s2;
+int a;
+int bar (struct st *s)
+{
+  struct st s3;
+  int b;
+  if (!s)
+    return 0;
+  foo (&s->a);
+  foo (&s2.a);
+  foo (&s3.a);
+  foo (&a);
+  foo (&b);
+}
+
+/* { dg-final { scan-ipa-dump "Setting nonnull for 0" "cp" } } */
+/* { dg-final { scan-tree-dump-times "if" 1 "vrp1" } } */