(safe_from_p): If EXP has a variable size, assume safe.

(preexpand_calls): Don't preexpand a call that returns a variable-sized object.

From-SVN: r8234

diff --git a/gcc/expr.c b/gcc/expr.c
index f7a9f8e65178c88c05141d67386125330240e9ed..f3aa69faabdbd7576b3633f6efa68b6b8f0b2397 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -3527,7 +3527,13 @@ safe_from_p (x, exp)
   rtx exp_rtl = 0;
   int i, nops;
 
-  if (x == 0)
+  if (x == 0
+      /* If EXP has varying size, we MUST use a target since we currently
+        have no way of allocating temporaries of variable size.  So we
+        assume here that something at a higher level has prevented a
+        clash.  This is somewhat bogus, but the best we can do.  */
+      || (TREE_TYPE (exp) != 0 &&
+         TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) != INTEGER_CST))
     return 1;
 
   /* If this is a subreg of a hard register, declare it unsafe, otherwise,
@@ -8316,7 +8322,9 @@ preexpand_calls (exp)
       /* Do nothing to built-in functions.  */
       if (TREE_CODE (TREE_OPERAND (exp, 0)) != ADDR_EXPR
          || TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)) != FUNCTION_DECL
-         || ! DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)))
+         || ! DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (exp, 0), 0))
+         /* Do nothing if the call returns a variable-sized object.  */
+         || TREE_CODE (TYPE_SIZE (TREE_TYPE(exp))) != INTEGER_CST)
        CALL_EXPR_RTL (exp) = expand_call (exp, NULL_RTX, 0);
       return;