Re: [Patch, middle-end] Fix PR 44878, IA64 build failure, partial inlining

[Richard Guenther <richard dot guenther at gmail dot com>]

On Wed, Jul 21, 2010 at 11:00 PM, Steve Ellcey <sje@cup.hp.com> wrote:
>
> Here is my latest patch to fix this problem. ?I think the issue involves
> the for_return argument to promote_function_mode. ?The comments for
> promote_function_mode simply say that this argument is non-zero if we
> are promoting a return value (and not an argument).
>
> But the routine calls targetm.calls.promote_function_mode and if that
> is set to default_promote_function_mode, the code checks for
> (for_return == 2) and calls promote_mode if it is. ?This behaviour
> is documented in tm.texi:
>
> ? ? ? ?@var{for_return} allows to distinguish the promotion of
> ? ? ? ?arguments and return values. ?If it is @code{1}, a return value
> ? ? ? ?is being promoted and @code{TARGET_FUNCTION_VALUE} must perform
> ? ? ? ?the same promotions done here. ?If it is @code{2}, the returned
> ? ? ? ?mode should be that of the register in which an incoming
> ? ? ? ?parameter is copied, or the outgoing result is computed; then
> ? ? ? ?the hook should return the same mode as @code{promote_mode},
> ? ? ? ?though the signedness may be different.
>
> Given this, it seems that expand_value_return should check for a
> reference return and call promote_function_mode with 2 instead of 1
> for that case. ?This patch allows me to bootstrap on IA64 and the
> testing seems to be going OK. ?Assuming it works, is this patch OK to
> checkin?

Hm, it sounds reasonable.  But I'd like someone more familiar with
the code review the patch.

Thanks,
Richard.

> Steve Ellcey
> sje@cup.hp.com
>
> Index: stmt.c
> ===================================================================
> --- stmt.c ? ? ?(revision 162360)
> +++ stmt.c ? ? ?(working copy)
> @@ -1595,8 +1595,11 @@ expand_value_return (rtx val)
> ? ? ? tree type = TREE_TYPE (decl);
> ? ? ? int unsignedp = TYPE_UNSIGNED (type);
> ? ? ? enum machine_mode old_mode = DECL_MODE (decl);
> - ? ? ?enum machine_mode mode = promote_function_mode (type, old_mode,
> - ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? &unsignedp, funtype, 1);
> + ? ? ?enum machine_mode mode;
> + ? ? ?if (DECL_BY_REFERENCE (decl))
> + ? ? ? ?mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 2);
> + ? ? ?else
> + ? ? ? ?mode = promote_function_mode (type, old_mode, &unsignedp, funtype, 1);
>
> ? ? ? if (mode != old_mode)
> ? ? ? ?val = convert_modes (mode, old_mode, val, unsignedp);
>
>