Handle (store &GV -> mem) as a store immediate. This often occurs for

Handle (store &GV -> mem) as a store immediate.  This often occurs for
printf format strings and other stuff.  Instead of generating this:

        movl $l1__2E_str_1, %eax
        movl %eax, (%esp)

we now emit:

        movl $l1__2E_str_1, (%esp)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21406 91177308-0d34-0410-b5e6-96231b3b80d8