2009-06-16 Richard Guenther <[email protected]>

	* tree-ssa-alias.c (is_escape_site): Remove.
	* tree-ssa-alias.h (enum escape_type): Remove.
	(is_escape_site): Likewise.
	* tree-ssa-structalias.c (find_func_aliases): Handle escapes
	via casts and asms without deferring to is_escape_site.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@148534 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2009-06-16  Richard Guenther  <[email protected]>
+
+	* tree-ssa-alias.c (is_escape_site): Remove.
+	* tree-ssa-alias.h (enum escape_type): Remove.
+	(is_escape_site): Likewise.
+	* tree-ssa-structalias.c (find_func_aliases): Handle escapes
+	via casts and asms without deferring to is_escape_site.
+
 2009-06-16  Jakub Jelinek  <[email protected]>
 
 	PR middle-end/40446

gcc/tree-ssa-alias.c

@@ -232,82 +232,6 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
   return pt_solutions_intersect (&pi1->pt, &pi2->pt);
 }
 
-/* Return true if STMT is an "escape" site from the current function.  Escape
-   sites those statements which might expose the address of a variable
-   outside the current function.  STMT is an escape site iff:
-
-   	1- STMT is a function call, or
-	2- STMT is an __asm__ expression, or
-	3- STMT is an assignment to a non-local variable, or
-	4- STMT is a return statement.
-
-   Return the type of escape site found, if we found one, or NO_ESCAPE
-   if none.  */
-
-enum escape_type
-is_escape_site (gimple stmt)
-{
-  if (is_gimple_call (stmt))
-    {
-      if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
-	return ESCAPE_TO_PURE_CONST;
-
-      return ESCAPE_TO_CALL;
-    }
-  else if (gimple_code (stmt) == GIMPLE_ASM)
-    return ESCAPE_TO_ASM;
-  else if (is_gimple_assign (stmt))
-    {
-      tree lhs = gimple_assign_lhs (stmt);
-
-      /* Get to the base of _REF nodes.  */
-      if (TREE_CODE (lhs) != SSA_NAME)
-	lhs = get_base_address (lhs);
-
-      /* If we couldn't recognize the LHS of the assignment, assume that it
-	 is a non-local store.  */
-      if (lhs == NULL_TREE)
-	return ESCAPE_UNKNOWN;
-
-      if (gimple_assign_cast_p (stmt))
-	{
-	  tree from = TREE_TYPE (gimple_assign_rhs1 (stmt));
-	  tree to = TREE_TYPE (lhs);
-
-	  /* If the RHS is a conversion between a pointer and an integer, the
-	     pointer escapes since we can't track the integer.  */
-	  if (POINTER_TYPE_P (from) && !POINTER_TYPE_P (to))
-	    return ESCAPE_BAD_CAST;
-	}
-
-      /* If the LHS is an SSA name, it can't possibly represent a non-local
-	 memory store.  */
-      if (TREE_CODE (lhs) == SSA_NAME)
-	return NO_ESCAPE;
-
-      /* If the LHS is a non-global decl, it isn't a non-local memory store.
-	 If the LHS escapes, the RHS escape is dealt with in the PTA solver.  */
-      if (DECL_P (lhs)
-	  && !is_global_var (lhs))
-	return NO_ESCAPE;
-
-      /* FIXME: LHS is not an SSA_NAME.  Even if it's an assignment to a
-	 local variables we cannot be sure if it will escape, because we
-	 don't have information about objects not in SSA form.  Need to
-	 implement something along the lines of
-
-	 J.-D. Choi, M. Gupta, M. J. Serrano, V. C. Sreedhar, and S. P.
-	 Midkiff, ``Escape analysis for java,'' in Proceedings of the
-	 Conference on Object-Oriented Programming Systems, Languages, and
-	 Applications (OOPSLA), pp. 1-19, 1999.  */
-      return ESCAPE_STORED_IN_GLOBAL;
-    }
-  else if (gimple_code (stmt) == GIMPLE_RETURN)
-    return ESCAPE_TO_RETURN;
-
-  return NO_ESCAPE;
-}
-
 
 /* Dump alias information on FILE.  */
 

gcc/tree-ssa-alias.h

@@ -24,26 +24,6 @@
 #include "coretypes.h"
 
 
-/* The reasons a variable may escape a function.  */
-enum escape_type 
-{
-  NO_ESCAPE = 0,			/* Doesn't escape.  */
-  ESCAPE_STORED_IN_GLOBAL = 1 << 0,
-  ESCAPE_TO_ASM = 1 << 1,		/* Passed by address to an assembly
-					   statement.  */
-  ESCAPE_TO_CALL = 1 << 2,		/* Escapes to a function call.  */
-  ESCAPE_BAD_CAST = 1 << 3,		/* Cast from pointer to integer */
-  ESCAPE_TO_RETURN = 1 << 4,		/* Returned from function.  */
-  ESCAPE_TO_PURE_CONST = 1 << 5,	/* Escapes to a pure or constant
-					   function call.  */
-  ESCAPE_IS_GLOBAL = 1 << 6,		/* Is a global variable.  */
-  ESCAPE_IS_PARM = 1 << 7,		/* Is an incoming function argument.  */
-  ESCAPE_UNKNOWN = 1 << 8		/* We believe it escapes for
-					   some reason not enumerated
-					   above.  */
-};
-
-
 /* The points-to solution.
 
    The points-to solution is a union of pt_vars and the abstract
@@ -107,7 +87,6 @@ typedef struct ao_ref_s
 extern void ao_ref_init (ao_ref *, tree);
 extern tree ao_ref_base (ao_ref *);
 extern alias_set_type ao_ref_alias_set (ao_ref *);
-extern enum escape_type is_escape_site (gimple);
 extern bool ptr_deref_may_alias_global_p (tree);
 extern bool refs_may_alias_p (tree, tree);
 extern bool refs_anti_dependent_p (tree, tree);

gcc/tree-ssa-structalias.c

@@ -3561,7 +3561,6 @@ find_func_aliases (gimple origt)
   VEC(ce_s, heap) *lhsc = NULL;
   VEC(ce_s, heap) *rhsc = NULL;
   struct constraint_expr *c;
-  enum escape_type stmt_escape_type;
 
   /* Now build constraints expressions.  */
   if (gimple_code (t) == GIMPLE_PHI)
@@ -3759,16 +3758,15 @@ find_func_aliases (gimple origt)
 	  && is_global_var (lhsop))
 	make_escape_constraint (rhsop);
     }
-
-  stmt_escape_type = is_escape_site (t);
-  if (stmt_escape_type == ESCAPE_BAD_CAST)
+  /* For conversions of pointers to non-pointers the pointer escapes.  */
+  else if (gimple_assign_cast_p (t)
+	   && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (t)))
+	   && !POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (t))))
     {
-      gcc_assert (is_gimple_assign (t));
-      gcc_assert (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (t))
-		  || gimple_assign_rhs_code (t) == VIEW_CONVERT_EXPR);
       make_escape_constraint (gimple_assign_rhs1 (t));
     }
-  else if (stmt_escape_type == ESCAPE_TO_ASM)
+  /* Handle asms conservatively by adding escape constraints to everything.  */
+  else if (gimple_code (t) == GIMPLE_ASM)
     {
       unsigned i, noutputs;
       const char **oconstraints;