builtins.c (fold_call_expr): Return realret.

2008-04-30  Rafael Espindola  <espindola@google.com>

	* builtins.c (fold_call_expr): Return realret.
	* tree-ssa-threadedge.c
	(record_temporary_equivalences_from_stmts_at_dest): Ignore calls to
	__builtin_object_size.

From-SVN: r134833

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ae74e649a9b9d0d0cd3867fb683522cc17ed247c..043723e06e05d35ec084afe5f8959cbc0bdced7f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2008-04-30  Rafael Espindola  <espindola@google.com>
+
+       * builtins.c (fold_call_expr): Return realret.
+       * tree-ssa-threadedge.c
+       (record_temporary_equivalences_from_stmts_at_dest): Ignore calls to
+       __builtin_object_size.
+
 2008-04-30  Seongbae Park  <seongbae.park@gmail.com>
 
        * gcc.c (wrapper_string): New variable.

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 321032dace026b09448c4724479ea3cd74c4ce61..2cb8fa03f9ed5275b038a06dc9addad8f39d19b6 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -10553,6 +10553,7 @@ fold_call_expr (tree exp, bool ignore)
                  if (CAN_HAVE_LOCATION_P (realret)
                      && !EXPR_HAS_LOCATION (realret))
                    SET_EXPR_LOCATION (realret, EXPR_LOCATION (exp));
+                 return realret;
                }
              return ret;
            }

diff --git a/gcc/tree-ssa-threadedge.c b/gcc/tree-ssa-threadedge.c
index d0d8fb229ab49dca796d066c20214180e7147635..b15de2752eb36ab998e73131784ba03ee0f2196c 100644 (file)
--- a/gcc/tree-ssa-threadedge.c
+++ b/gcc/tree-ssa-threadedge.c
@@ -226,6 +226,7 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
   for (bsi = bsi_start (e->dest); ! bsi_end_p (bsi); bsi_next (&bsi))
     {
       tree cached_lhs = NULL;
+      tree rhs;
 
       stmt = bsi_stmt (bsi);
 
@@ -252,6 +253,32 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
          || TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 0)) != SSA_NAME)
        continue;
 
+      rhs = GIMPLE_STMT_OPERAND (stmt, 1);
+
+      /* The result of __builtin_object_size depends on all the arguments
+        of a phi node. Temporarily using only one edge produces invalid
+        results. For example
+
+        if (x < 6)
+          goto l;
+        else
+          goto l;
+
+        l:
+        r = PHI <&w[2].a[1](2), &a.a[6](3)>
+        __builtin_object_size (r, 0)
+
+        The result of __builtin_object_size is defined to be the maximum of
+        remaining bytes. If we use only one edge on the phi, the result will
+        change to be the remaining bytes for the corresponding phi argument. */
+
+      if (TREE_CODE (rhs) == CALL_EXPR)
+       {
+         tree fndecl = get_callee_fndecl (rhs);
+         if (fndecl && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_OBJECT_SIZE)
+           continue;
+       }
+
       /* At this point we have a statement which assigns an RHS to an
         SSA_VAR on the LHS.  We want to try and simplify this statement
         to expose more context sensitive equivalences which in turn may
@@ -259,10 +286,10 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
 
         Handle simple copy operations as well as implied copies from
         ASSERT_EXPRs.  */
-      if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == SSA_NAME)
-       cached_lhs = GIMPLE_STMT_OPERAND (stmt, 1);
-      else if (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ASSERT_EXPR)
-       cached_lhs = TREE_OPERAND (GIMPLE_STMT_OPERAND (stmt, 1), 0);
+      if (TREE_CODE (rhs) == SSA_NAME)
+       cached_lhs = rhs;
+      else if (TREE_CODE (rhs) == ASSERT_EXPR)
+       cached_lhs = TREE_OPERAND (rhs, 0);
       else
        {
          /* A statement that is not a trivial copy or ASSERT_EXPR.