Teach stack promotion to walk the CFG when a potential reuse of an allocation is found to see if it can actually happen instead of just assuming it will. This allows it to catch cases like {{{ int i; Foo f; while (cond(i)) f = new Foo(i++); return f.value; }}} where it previously wouldn't because a phi using the allocation would appear in the condition block to propagate it to the use after the loop.

enum
{
    LLVMnone,
    LLVMintrinsic,
    LLVMno_typeinfo,
    LLVMno_moduleinfo,
    LLVMalloca,
    LLVMva_start,
    LLVMva_copy,
    LLVMva_end,
    LLVMva_arg,
    LLVMinline_asm
};