This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: RFA: enable LRA for rs6000 [patch for WRF]

On Mon, Apr 22, 2013 at 03:26:45PM -0400, Vladimir Makarov wrote:
> On 13-04-22 12:35 AM, Alan Modra wrote:
> >On Fri, Apr 19, 2013 at 05:16:43PM -0400, Vladimir Makarov wrote:
> >>   I don't understand what this check means and what comments ??? means too.
> >A lo_sum mem is only valid if you know it won't be offset (or that
> >offsetting will never cross a 64k+32k boundary).  If the access is
> >smaller than a word then the load or store can be done in one insn.
> >No offset required.  If the access is a DFmode *and* you are loading
> >or storing a floating point reg, then the access is also done in one
> >insn.  The ??? comment is referring to the fact that you don't know
> >for sure that the DFmode is in a floating point reg.  It usually is,
> >but may be in two general purpose regs.  Which then need an offset to
> >load/store the second reg.
> >
> Alan, thanks for the explanation. I'll search for another solution.

I'm suspecting secondary_reload needs more tuning for TF/TD modes.

Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460, USA
email:, phone: +1 (978) 899-4797

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]