[PATCH] Pass correct memory attributes for build constant

[Kito Cheng]

Hi all:
  This patch is fix constant memory's symbol_ref don't have right
alignment info since `exp` don't set alignment (and should not set
alignment info for `exp`)  , use `decl` to set_mem_attributes for
right alignment info.

ChangLog
2014-06-25  Kito Cheng  <k...@0xlab.org>

        * varasm.c (build_constant_desc): Use decl to set mem
        attributes since exp don't have correct aligment info.

diff --git a/gcc/varasm.c b/gcc/varasm.c
index 7be56f1..6e7ca5a 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -3201,7 +3201,7 @@ build_constant_desc (tree exp)
   TREE_CONSTANT_POOL_ADDRESS_P (symbol) = 1;
 
   rtl = gen_const_mem (TYPE_MODE (TREE_TYPE (exp)), symbol);
-  set_mem_attributes (rtl, exp, 1);
+  set_mem_attributes (rtl, decl, 1);
   set_mem_alias_set (rtl, 0);
   set_mem_alias_set (rtl, const_alias_set);