* tree-sra.c (sra_walk_fns) <ldst>: Document new restriction.

[pf3gnuchains/gcc-fork.git] / gcc / tree-sra.c

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index cb8f63d..ef7707f 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -685,8 +685,8 @@ struct sra_walk_fns
   void (*init) (struct sra_elt *elt, tree value, block_stmt_iterator *bsi);
 
   /* Invoked when we have a copy between one scalarizable reference ELT
-     and one non-scalarizable reference OTHER.  IS_OUTPUT is true if ELT
-     is on the left-hand side.  */
+     and one non-scalarizable reference OTHER without side-effects. 
+     IS_OUTPUT is true if ELT is on the left-hand side.  */
   void (*ldst) (struct sra_elt *elt, tree other,
                block_stmt_iterator *bsi, bool is_output);
 
@@ -908,7 +908,7 @@ sra_walk_gimple_modify_stmt (tree expr, block_stmt_iterator *bsi,
   /* If the RHS is scalarizable, handle it.  There are only two cases.  */
   if (rhs_elt)
     {
-      if (!rhs_elt->is_scalar)
+      if (!rhs_elt->is_scalar && !TREE_SIDE_EFFECTS (lhs))
        fns->ldst (rhs_elt, lhs, bsi, false);
       else
        fns->use (rhs_elt, &GIMPLE_STMT_OPERAND (expr, 1), bsi, false, false);
@@ -951,7 +951,8 @@ sra_walk_gimple_modify_stmt (tree expr, block_stmt_iterator *bsi,
         The lvalue requirement prevents us from trying to directly scalarize
         the result of a function call.  Which would result in trying to call
         the function multiple times, and other evil things.  */
-      else if (!lhs_elt->is_scalar && is_gimple_addressable (rhs))
+      else if (!lhs_elt->is_scalar
+              && !TREE_SIDE_EFFECTS (rhs) && is_gimple_addressable (rhs))
        fns->ldst (lhs_elt, rhs, bsi, true);
 
       /* Otherwise we're being used in some context that requires the