[PATCH][PR67671] Handle restrict pointer references as restrict in AA

[Tom de Vries]

Hi,

Consider this test-case:
...
struct ps
{
  int *__restrict__ p;
};
f (struct ps &__restrict__ ps1)
{
  *(ps1.p) = 1;
}
...

Atm (meaning after the fix for PR67666) for this test-case, we register 
two clique/base annotations, one for the load of pointer ps1.p and one 
for the store to that pointer:
...
void f(ps&) (struct psD.2252 & restrict ps1D.2255)
{
  intD.9 * _3;

  # VUSE <.MEM_1(D)>
  # PT = { D.2262 } (nonlocal)
  _3 = MEM[(struct psD.2252 &)ps1_2(D) clique 1 base 1].pD.2254;

  # .MEM_4 = VDEF <.MEM_1(D)>
  MEM[(intD.9 *)_3 clique 1 base 2] = 1;
...


If we rewrite the test-case by replacing the struct with its only field, 
we get:
...
f (int *__restrict__ &__restrict__ p)
{
  *p = 1;
}
...

However, in this case, we register only one clique/base annotation, for 
the load of pointer p, but not for the store to pointer p:
...
void f(int* __restrict__&) (intD.9 * restrict & restrict pD.2255)
{
  intD.9 * _3;

  # VUSE <.MEM_1(D)>
  # PT = nonlocal escaped
  _3 = MEM[(intD.9 * restrict &)p_2(D) clique 1 base 1];

  # .MEM_4 = VDEF <.MEM_1(D)>
  *_3 = 1;
...


This patch makes sure we register both clique/base annotations for the 
the second example.

Bootstrapped and reg-tested on x86_64.

OK for trunk?

Thanks,
- Tom
Handle restrict pointer references as restrict in AA

2015-09-22  Tom de Vries  <t...@codesourcery.com>

	PR tree-optimization/67671
	* tree-ssa-structalias.c (create_variable_info_for_1): Handle restrict
	pointer references as restrict.

	* g++.dg/pr67671.C: New test.
---
 gcc/testsuite/g++.dg/pr67671.C | 12 ++++++++++++
 gcc/tree-ssa-structalias.c     |  3 +++
 2 files changed, 15 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/pr67671.C

diff --git a/gcc/testsuite/g++.dg/pr67671.C b/gcc/testsuite/g++.dg/pr67671.C
new file mode 100644
index 0000000..952ea4f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr67671.C
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-ealias-all" }
+
+void
+f (int *__restrict__ &__restrict__ p)
+{
+  *p = 1;
+}
+
+// { dg-final { scan-tree-dump-times "clique 1 base 1" 1 "ealias" } }
+// { dg-final { scan-tree-dump-times "clique 1 base 2" 1 "ealias" } }
+// { dg-final { scan-tree-dump-times "(?n)clique .* base .*" 2 "ealias" } }
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index b5b9d0a..0a8998c 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -5684,6 +5684,9 @@ create_variable_info_for_1 (tree decl, const char *name)
       vi->fullsize = tree_to_uhwi (declsize);
       vi->size = vi->fullsize;
       vi->is_full_var = true;
+      if (POINTER_TYPE_P (TREE_TYPE (decl))
+	  && TYPE_RESTRICT (TREE_TYPE (decl)))
+	vi->only_restrict_pointers = 1;
       fieldstack.release ();
       return vi;
     }
-- 
1.9.1