[PATCH] Re-fix PR target/47755 on powerpc VSX

[Michael Meissner]

On Tue, Mar 08, 2011 at 07:12:27PM -0500, David Edelsohn wrote:
> On Tue, Mar 8, 2011 at 6:56 PM, Michael Meissner
> <meissner@linux.vnet.ibm.com> wrote:
> > PR 47755 fixed some bugs on VSX with V2DI constants, but the patch itself had
> > problems. Â In particular, the easy_altivec_constant support assumed the largest
> > int size was SImode. Â This would cause the compiler to generate VSPLTI{W,S,B}
> > to load up a constant instead of loading it up from memory.
> >
> > This patch only allows (vector long long) { 0, 0 } and
> > (vector long long) { -1, -1 } as easy V2DI constants. Â There are some other
> > constants that could be generated using the Altivec instructions in the future.
> >
> > I bootstrapped this patch and had no regressions with make check. Â Is it ok to
> > install?
> >
> > [gcc]
> > 2011-03-08  Michael Meissner  <meissner@linux.vnet.ibm.com>
> >
> > Â  Â  Â  Â PR target/47755
> > Â  Â  Â  Â * config/rs6000/rs6000.c (easy_altivec_constant): Correctly handle
> > Â  Â  Â  Â V2DI/V2DF constants. Â Only all 0's or all 1's are easy.
> > Â  Â  Â  Â (output_vec_const_move): Ditto.
> >
> > [gcc/testsuite]
> > 2011-03-08  Michael Meissner  <meissner@linux.vnet.ibm.com>
> >
> > Â  Â  Â  Â PR target/47755
> > Â  Â  Â  Â * gcc.target/powerpc/pr47755-2.c: New file.
> 
> Should the CONST_INT test be wrapped in #ifdef HOST_BITS_PER_WIDE_INT?

I dunno.  Given that it is harmless on 64-bit, I would tend to not put the
#ifdef there.  But I would have no objection to adding it.
 
> Okay.
> 
> Thanks, David

-- 
Michael Meissner, IBM
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