Backing out Chris' last commit. It's breaking llvm-gcc bootstrapping.

It's turning:
        movl -24(%ebp), %esp
        subl $16, %esp
        movl -24(%ebp), %ecx
into
        movl -24(%ebp), %esp
        subl $16, %esp
        movl %esp, (%esp)

llvm-svn: 30902