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Re: PATCH: PR target/35657: TDmode isn't aligned at 128bit when passing to a function
- From: "Uros Bizjak" <ubizjak at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: "GCC Patches" <gcc-patches at gcc dot gnu dot org>, "Girkar, Milind" <milind dot girkar at intel dot com>, david dot l dot kreitz at intel dot com, "Jan Hubicka" <hubicka at ucw dot cz>
- Date: Thu, 27 Mar 2008 15:02:15 +0100
- Subject: Re: PATCH: PR target/35657: TDmode isn't aligned at 128bit when passing to a function
- References: <6dc9ffc80803270633v25be5051i90bf86a6a2182822@mail.gmail.com>
On Thu, Mar 27, 2008 at 2:33 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> Decimal floating point isn't covered by the ia32 psABI. Gcc is the
> first compiler
> which implements DFP on ia32 and is defining the de facto DFP psABI. I don't
> see a reason not to align them to their natural boundary when passing them
> on stack. I'd like to install it on trunk and 4.3.1.
I assume that DFP passing will be specified in the next revision of psABI.
The patch is OK for mainline, but please revert runtime part of my
previous patch [1][2] that forced unaligned moves when TDmode (TImode)
values were moved to/from the stack. There is no need for this
functionality, once TDmode values are aligned to their natural
boundaries.
Also, please re-test your change (with my patch reverted) with
"--with-arch=core2" configured compiler, to check if problems [3]
resurfaced.
Regarding 4.3.1 support - since this is an ABI change w.r.t released
compiler, RMs should have their last word. IMO, at least a notice in
release notes is needed
Thanks,
Uros.
[1] http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01716.html
[2] http://gcc.gnu.org/ml/gcc-patches/2007-05/msg01863.html
[3] http://gcc.gnu.org/ml/gcc-testresults/2007-05/msg01171.html