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Re: Fix argument pushes to unaligned stack slots
- From: Ian Lance Taylor <iant at google dot com>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: 08 Feb 2007 07:32:02 -0800
- Subject: Re: Fix argument pushes to unaligned stack slots
- References: <Pine.LNX.4.64.0702070144100.25338@digraph.polyomino.org.uk>
"Joseph S. Myers" <joseph@codesourcery.com> writes:
> 2007-02-06 Joseph Myers <joseph@codesourcery.com>
>
> * expr.c (emit_push_insn): If STRICT_ALIGNMENT, copy to an
> unaligned stack slot via a suitably aligned slot.
This patch concerns me because the caller, in store_one_arg in
calls.c, will always pass PARM_BOUNDARY. In the past this never
mattered since the alignment was effectively ignored for mode !=
BLKmode. My concern is that your patch will start causing some
targets to unnecessarily stage large arguments through a stack
temporary. Can you give me a reason why that will not happen? Or
change the caller to pass in the correct alignment based on
arg->locate.boundary which is ultimately based on
FUNCTION_ARG_BOUNDARY?
Thanks.
Ian