[PATCH, 2/2] Handle recursive restrict pointer in create_variable_info_for_1

[Tom de Vries]

Hi,

this patch enables recursive restrict handling in 
create_variable_info_for_1.

This allows us to interpret all restricts in a function parameter
"int *restrict *restrict *restrict a".

This patch is the first step towards implementing a generic fix for PR67742.

Bootstrapped and reg-tested on x86_64.

OK for trunk?

Thanks,
- Tom
Handle recursive restrict pointer in create_variable_info_for_1

2015-10-26  Tom de Vries  <t...@codesourcery.com>

	* tree-ssa-structalias.c (create_variable_info_for_1): Enable recursive
	handling of restrict pointers.
	(make_restrict_var_constraints): Handle restrict vars recursively.

	* gcc.dg/tree-ssa/restrict-7.c: New test.
---
 gcc/testsuite/gcc.dg/tree-ssa/restrict-7.c | 12 ++++++++++++
 gcc/tree-ssa-structalias.c                 | 13 +++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/restrict-7.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/restrict-7.c b/gcc/testsuite/gcc.dg/tree-ssa/restrict-7.c
new file mode 100644
index 0000000..f7a68c7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/restrict-7.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-fre1" } */
+
+int
+f (int *__restrict__ *__restrict__ *__restrict__ a, int *b)
+{
+  *b = 1;
+  ***a  = 2;
+  return *b;
+}
+
+/* { dg-final { scan-tree-dump-times "return 1" 1 "fre1" } } */
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 3fdad3a..3839f67 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -5696,7 +5696,7 @@ create_variable_info_for_1 (tree decl, const char *name, bool handle_param)
 	  varinfo_t rvi;
 	  tree heapvar = build_fake_var_decl (TREE_TYPE (decl_type));
 	  DECL_EXTERNAL (heapvar) = 1;
-	  rvi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS", false);
+	  rvi = create_variable_info_for_1 (heapvar, "PARM_NOALIAS", true);
 	  rvi->is_restrict_var = 1;
 	  insert_vi_for_tree (heapvar, rvi);
 	  vi->restrict_pointed_var = rvi->id;
@@ -5867,7 +5867,16 @@ make_restrict_var_constraints (varinfo_t vi)
     if (vi->may_have_pointers)
       {
 	if (vi->only_restrict_pointers)
-	  make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
+	  {
+	    varinfo_t rvi = get_varinfo (vi->restrict_pointed_var);
+	    if (rvi != NULL)
+	      {
+		make_constraint_from (vi, rvi->id);
+		make_restrict_var_constraints (rvi);
+	      }
+	    else
+	      make_constraint_from_global_restrict (vi, "GLOBAL_RESTRICT");
+	  }
 	else
 	  make_copy_constraint (vi, nonlocal_id);
       }
-- 
1.9.1