Comment 15 for bug 731665

The problem is due to prologue_seq in thread_prologue_and_epilogue_insns() being uninitialised and defaulting to the value of '1'. This is an invalid rtx pointer which fails downstream in emit_insn().

On my cross compiler, prologue_seq happened to be a good value and hence inserts wrong code instead of failing.

The change was introduced in gcc-linaro/4.5,revno=99474 as part of the shrink-wrap optimisation. It should happen on other naked functions. Initialising prologue_seq to NULL_RTX should work around the problem.