[RFC][IPA-VRP] ADDR_EXPR and nonnull

kugan kugan.vivekanandarajah@linaro.org
Thu Oct 20 03:13:00 GMT 2016



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.  */
+		  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..affd8b9 100644
--- a/gcc/ipa-prop.c
+++ b/gcc/ipa-prop.c
@@ -1670,9 +1670,35 @@ 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 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.  */
+		  addr_nonzero = true;
+		}
+	      else
+		{
+		  /* If symbol address is nonzero_address.  */
+		  node = varpool_node::get (base);
+		  if (node && node->nonzero_address ())
+		    addr_nonzero = true;
+		}
+	    }
+
+	  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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