re PR tree-optimization/45982 (PTA does not track integers)

2010-10-13  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/45982
	* tree-ssa-structalias.c (make_constraints_to): New function.
	(make_constraint_to): Implement in terms of make_constraints_to.
	(find_func_aliases): Properly make return values of pure/const
	functions escape if they assign to sth that is not a pointer.

	* gcc.dg/torture/pr45982.c: New testcase.
	* gcc.dg/tree-ssa/pr24287.c: Adjust.
	* gcc.dg/tree-ssa/pta-callused.c: Likewise.
	* gcc.dg/torture/pr39074-2.c: Likewise.

From-SVN: r165418

gcc/ChangeLog

 2010-10-13  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/45982
+	* tree-ssa-structalias.c (make_constraints_to): New function.
+	(make_constraint_to): Implement in terms of make_constraints_to.
+	(find_func_aliases): Properly make return values of pure/const
+	functions escape if they assign to sth that is not a pointer.
+
+2010-10-13  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/45874
 	* cgraphunit.c (cgraph_redirect_edge_call_stmt_to_callee):
 	Fixup the CFG when EH was fixed up.

gcc/testsuite/ChangeLog

 2010-10-13  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/45982
+	* gcc.dg/torture/pr45982.c: New testcase.
+	* gcc.dg/tree-ssa/pr24287.c: Adjust.
+	* gcc.dg/tree-ssa/pta-callused.c: Likewise.
+	* gcc.dg/torture/pr39074-2.c: Likewise.
+
+2010-10-13  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/45874
 	* g++.dg/torture/pr45874.C: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr39074-2.c

@@ -30,5 +30,5 @@ int main()
   return 0;
 }
 
-/* { dg-final { scan-tree-dump "y.._., points-to vars: { i }" "alias" } } */
+/* { dg-final { scan-tree-dump "y.._., points-to non-local, points-to escaped, points-to vars: { i }" "alias" } } */
 /* { dg-final { cleanup-tree-dump "alias" } } */

gcc/testsuite/gcc.dg/torture/pr45982.c

+/* { dg-do run } */
+
+#include <stdint.h>
+
+extern void abort (void);
+
+uintptr_t __attribute__((pure,noinline,noclone))
+foo (int *a)
+{
+  return (uintptr_t) a;
+}
+
+void __attribute__((noinline,noclone))
+bar (uintptr_t a)
+{
+  int *p = (int *)a;
+  *p = 1;
+}
+
+int main()
+{
+  int t = 0;
+  bar (foo (&t));
+  if (t != 1)
+    abort ();
+  return 0;
+}

gcc/testsuite/gcc.dg/tree-ssa/pr24287.c

@@ -9,11 +9,14 @@ void link_error();
 int g(void)
 {
   int t = 0, t1 = 2;
+  /* ???  That's not true.  The pointers escape to the integer return
+     value which we do not track in PTA.  */
   int t2 = h(&t, &t1);
   if (t != 0)
     link_error ();
   if (t1 != 2)
     link_error ();
+  /* ???  And it would finally escape here even if we did.  */
   g1(t2);
   if (t != 0)
     link_error ();
@@ -21,5 +24,6 @@ int g(void)
     link_error ();
   return t2 == 2;
 }
-/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized" } } */
+/* We are allowed to optimize the first two link_error calls.  */
+/* { dg-final { scan-tree-dump-times "link_error" 2 "optimized" } } */
 /* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/pta-callused.c

@@ -5,7 +5,7 @@ struct Foo {
   int *p, *q;
 };
 
-int foo (int ***x) __attribute__((pure));
+int *foo (int ***x) __attribute__((pure));
 
 int bar (int b)
 {
@@ -19,7 +19,7 @@ int bar (int b)
     q = &f.p;
   else
     q = &f.q;
-  return foo (&q);
+  return *foo (&q);
 }
 
 /* { dg-final { scan-tree-dump "CALLUSED = { f.* i q }" "alias" } } */

gcc/tree-ssa-structalias.c

@@ -3563,12 +3563,11 @@ do_structure_copy (tree lhsop, tree rhsop)
   VEC_free (ce_s, heap, rhsc);
 }
 
-/* Create a constraint ID = OP.  */
+/* Create constraints ID = { rhsc }.  */
 
 static void
-make_constraint_to (unsigned id, tree op)
+make_constraints_to (unsigned id, VEC(ce_s, heap) *rhsc)
 {
-  VEC(ce_s, heap) *rhsc = NULL;
   struct constraint_expr *c;
   struct constraint_expr includes;
   unsigned int j;
@@ -3577,9 +3576,18 @@ make_constraint_to (unsigned id, tree op)
   includes.offset = 0;
   includes.type = SCALAR;
 
-  get_constraint_for_rhs (op, &rhsc);
   FOR_EACH_VEC_ELT (ce_s, rhsc, j, c)
     process_constraint (new_constraint (includes, *c));
+}
+
+/* Create a constraint ID = OP.  */
+
+static void
+make_constraint_to (unsigned id, tree op)
+{
+  VEC(ce_s, heap) *rhsc = NULL;
+  get_constraint_for_rhs (op, &rhsc);
+  make_constraints_to (id, rhsc);
   VEC_free (ce_s, heap, rhsc);
 }
 
@@ -4334,8 +4342,7 @@ find_func_aliases (gimple origt)
 	     of global memory but not of escaped memory.  */
 	  if (flags & (ECF_CONST|ECF_NOVOPS))
 	    {
-	      if (gimple_call_lhs (t)
-		  && could_have_pointers (gimple_call_lhs (t)))
+	      if (gimple_call_lhs (t))
 		handle_const_call (t, &rhsc);
 	    }
 	  /* Pure functions can return addresses in and of memory
@@ -4345,9 +4352,17 @@ find_func_aliases (gimple origt)
 	    handle_pure_call (t, &rhsc);
 	  else
 	    handle_rhs_call (t, &rhsc);
-	  if (gimple_call_lhs (t)
-	      && could_have_pointers (gimple_call_lhs (t)))
-	    handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
+	  if (gimple_call_lhs (t))
+	    {
+	      if (could_have_pointers (gimple_call_lhs (t)))
+		handle_lhs_call (t, gimple_call_lhs (t), flags, rhsc, fndecl);
+	      /* Similar to conversions a result that is not a pointer
+		 is an escape point for any pointer the function might
+		 return.  */
+	      else if (flags & (ECF_CONST|ECF_PURE
+				|ECF_NOVOPS|ECF_LOOPING_CONST_OR_PURE))
+		make_constraints_to (escaped_id, rhsc);
+	    }
 	  VEC_free (ce_s, heap, rhsc);
 	}
       else