[RFC][IPA-VRP] ADDR_EXPR and nonnull

kugan kugan.vivekanandarajah@linaro.org
Thu Oct 20 11:56:00 GMT 2016


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

Attached patch does this. Bootstrapped and regression tested on 
x86_64-linux-gnu. Is this OK?

Thanks,
Kugan

>
> Richard.
>
>> +		  addr_nonzero = true;
>> +		}
>> +	      else
>> +		{
>> +		  /* If symbol address is nonzero_address.  */
>> +		  node = varpool_node::get (base);
>> +		  if (node && node->nonzero_address ())
>> +		    addr_nonzero = true;
>> +		}
>> +	    }
>>
>> Attached patch passes bootstrap and regression testing on x86_64-linu-gnu.
>>
>> Thanks,
>> Kugan
>>
>>>
>>> Honza
>>>>
>>>> Richard.
>>>>
>>>>> Thanks,
>>>>> Kugan
>>>>>
>>>>>>
>>>>>> Richard.
>>>>>>
>>>>>>> Attached patch bootstraps and regression testing didn't introduce
>>>>>>> any new
>>>>>>> regressions.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Kugan
>>>>>>>
>>>>>>>
>>>>>>> gcc/ChangeLog:
>>>>>>>
>>>>>>> 2016-10-19  Kugan Vivekanandarajah  <kuganv@linaro.org>
>>>>>>>
>>>>>>> 	* ipa-prop.c (ipa_compute_jump_functions_for_edge): Set
>>>>>>> 	value range to nonull for ADDR_EXPR.
>>>>>>>
>>>>>>> gcc/testsuite/ChangeLog:
>>>>>>>
>>>>>>> 2016-10-19  Kugan Vivekanandarajah  <kuganv@linaro.org>
>>>>>>>
>>>>>>> 	* gcc.dg/ipa/vrp5.c: New test.
>>>>>>> 	* gcc.dg/ipa/vrp6.c: New test.
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>> --
>>>> Richard Biener <rguenther@suse.de>
>>>> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
>>>> 21284 (AG Nuernberg)
>>
>
-------------- next part --------------
diff --git a/gcc/ipa-prop.c b/gcc/ipa-prop.c
index 353b638..3fe60d6 100644
--- a/gcc/ipa-prop.c
+++ b/gcc/ipa-prop.c
@@ -1670,9 +1670,26 @@ ipa_compute_jump_functions_for_edge (struct ipa_func_body_info *fbi,
 
       if (POINTER_TYPE_P (TREE_TYPE (arg)))
 	{
-	  if (TREE_CODE (arg) == SSA_NAME
-	      && param_type
-	      && get_ptr_nonnull (arg))
+	  bool addr_nonzero = false;
+
+	  if (TREE_CODE (arg) == ADDR_EXPR)
+	    {
+	      /* See if the ADDR_EXPR is nonnull.  */
+	      tree base = get_base_address (TREE_OPERAND (arg, 0));
+
+	      if (TREE_CODE (base) == CONST_DECL
+		  || TREE_CODE (base) == PARM_DECL
+		  || TREE_CODE (base) == RESULT_DECL)
+		addr_nonzero = true;
+	      else if (VAR_P (base))
+		addr_nonzero = ! is_global_var (base)
+		  || (varpool_node::get (base)->nonzero_address ());
+	    }
+
+	  if ((TREE_CODE (arg) == SSA_NAME
+	       && param_type
+	       && get_ptr_nonnull (arg))
+	      || 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" } } */


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