PR c++/55877

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

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 1f533a3..d56650d 100644 (file)
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -5117,6 +5117,7 @@ gimple_duplicate_bb (basic_block bb)
     {
       def_operand_p def_p;
       ssa_op_iter op_iter;
+      tree lhs;
 
       stmt = gsi_stmt (gsi);
       if (gimple_code (stmt) == GIMPLE_LABEL)
@@ -5130,6 +5131,24 @@ gimple_duplicate_bb (basic_block bb)
       maybe_duplicate_eh_stmt (copy, stmt);
       gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
 
+      /* When copying around a stmt writing into a local non-user
+        aggregate, make sure it won't share stack slot with other
+        vars.  */
+      lhs = gimple_get_lhs (stmt);
+      if (lhs && TREE_CODE (lhs) != SSA_NAME)
+       {
+         tree base = get_base_address (lhs);
+         if (base
+             && (TREE_CODE (base) == VAR_DECL
+                 || TREE_CODE (base) == RESULT_DECL)
+             && DECL_IGNORED_P (base)
+             && !TREE_STATIC (base)
+             && !DECL_EXTERNAL (base)
+             && (TREE_CODE (base) != VAR_DECL
+                 || !DECL_HAS_VALUE_EXPR_P (base)))
+           DECL_NONSHAREABLE (base) = 1;
+       }
+
       /* Create new names for all the definitions created by COPY and
         add replacement mappings for each new name.  */
       FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)