Hi!
On Tue, Sep 22, 2020 at 09:55:12AM +0930, Alan Modra wrote:
> Calls from split-stack code to non-split-stack code need to expand
> mapped stack memory via __morestack. Even tail calls.
>
> __morestack is quite a surprising function on powerpc in that it calls
> back to its caller, and a tail call will continue running in the
> context of extra mapped stack.
Also known as "pure evil" :-)
> PR target/97107
> * config/rs6000/rs6000-internal.h (struct rs6000_stack): Improve
> calls_p comment.
> * config/rs6000/rs6000-logue.c (rs6000_stack_info): Likewise.
> (rs6000_expand_split_stack_prologue): Emit the prologue for
> functions that make a sibling call.
> if (!info->push_p)
> - return;
> + {
> + /* We need the -fsplit-stack prologue for functions that make
> + tail calls. Tail calls don't count against crtl->is_leaf. */
> + for (insn = get_topmost_sequence ()->first; insn; insn = NEXT_INSN
> (insn))
> + if (CALL_P (insn))
> + break;
> + if (!insn)
> + return;
> + }
I don't think that get_topmost_sequence is correct.
Other than that this is fine for trunk (and backports). Thanks!
Segher
