On Thu, 2017-12-07 at 12:21 +0100, Richard Biener wrote:
> On Wed, Dec 6, 2017 at 5:36 PM, Will Schmidt <will_schm...@vnet.ibm.com>
> wrote:
> > Hi,
> > Add support for gimple folding of splat_u{8,16,32}.
> > Testcase coverage is primarily handled by existing tests
> > testsuite/gcc.target/powerpc/fold-vec-splat_*.c
> >
> > One new test added to verify we continue to receive
> > an 'invalid argument, must be a 5-bit immediate' error
> > when we try to splat a non-constant value.
> >
> > Regtests currently running across assorted power systems.
> > OK for trunk with successful results?
> >
> > Thanks
> > -Will
> >
> > [gcc]
> >
> > 2017-12-05 Will Schmidt <will_schm...@vnet.ibm.com>
> >
> > * config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Add support
> > for
> > early folding of splat_u{8,16,32}.
> >
> > [testsuite]
> >
> > 2017-12-05 Will Schmidt <will_schm...@vnet.ibm.com>
> >
> > * gcc.target/powerpc/fold-vec-splat-misc-invalid.c: New.
> >
> > diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> > index 045a014..1470557 100644
> > --- a/gcc/config/rs6000/rs6000.c
> > +++ b/gcc/config/rs6000/rs6000.c
> > @@ -16614,10 +16614,33 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator
> > *gsi)
> > case VSX_BUILTIN_CMPLE_2DI:
> > case VSX_BUILTIN_CMPLE_U2DI:
> > fold_compare_helper (gsi, LE_EXPR, stmt);
> > return true;
> >
> > + /* flavors of vec_splat_[us]{8,16,32}. */
> > + case ALTIVEC_BUILTIN_VSPLTISB:
> > + case ALTIVEC_BUILTIN_VSPLTISH:
> > + case ALTIVEC_BUILTIN_VSPLTISW:
> > + {
> > + arg0 = gimple_call_arg (stmt, 0);
> > + lhs = gimple_call_lhs (stmt);
> > + /* Only fold the vec_splat_*() if arg0 is constant. */
> > + if ( TREE_CODE (arg0) != INTEGER_CST)
> > + return false;
>
> Is there a reason to not do this for non-constants? (even not for
> float constants?)
The full regtest failed elsewhere in the suite if I didn't limit this to
just constants, which is part of why I also added the dg-error checking
test. [Something in the area of gcc/config/rs6000/emmintrin.h
_mm_slli_epi16() which calls vec_splat_s16(__B), iirc.] The net of that
seemed to be that I had folded something I shouldn't have. I'll
incorporate the other suggested changes from you and Jakub and Segher,
and double-check the results.
> You should probably double-check there is a LHS, folding runs before DCE.
Anything without a LHS gets rejected early in
rs6000_gimple_fold_builtin() , so I should be covered there. :-)
> > + tree splat_value = build_int_cst (TREE_TYPE (TREE_TYPE (lhs)),
> > + TREE_INT_CST_LOW (arg0));
> > + vec<constructor_elt, va_gc> *ctor_elts = NULL;
> > + unsigned int n_elts = TYPE_VECTOR_SUBPARTS (TREE_TYPE (lhs));
> > + for (unsigned int i=0; i < n_elts ; i++)
> > + CONSTRUCTOR_APPEND_ELT (ctor_elts, NULL_TREE, splat_value);
> > + tree splat_tree = build_constructor (TREE_TYPE (lhs), ctor_elts);
>
> Just use
>
> tree slat_tree = build_vector_from_val (splat_value);
>
> that would also work for non-constants btw.
Alright, thanks. :-)
-Will
>
> > + g = gimple_build_assign (lhs, splat_tree);
> > + gimple_set_location (g, gimple_location (stmt));
> > + gsi_replace (gsi, g, true);
> > + return true;
> > + }
> > +
> > default:
> > if (TARGET_DEBUG_BUILTIN)
> > fprintf (stderr, "gimple builtin intrinsic not matched:%d %s %s\n",
> > fn_code, fn_name1, fn_name2);
> > break;
> > diff --git a/gcc/testsuite/gcc.target/powerpc/fold-vec-splat-misc-invalid.c
> > b/gcc/testsuite/gcc.target/powerpc/fold-vec-splat-misc-invalid.c
> > new file mode 100644
> > index 0000000..20f5b05
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/powerpc/fold-vec-splat-misc-invalid.c
> > @@ -0,0 +1,33 @@
> > +/* Verify that overloaded built-ins for vec_splat_s8 and vec_splat_s16
> > + generate errors as expected when we attempt to use invalid inputs. */
> > +
> > +/* { dg-do compile } */
> > +/* { dg-require-effective-target powerpc_vsx_ok } */
> > +/* { dg-options "-mvsx -O2" } */
> > +
> > +#include <altivec.h>
> > +
> > +vector signed short
> > +testss_1 (unsigned int ui)
> > +{
> > + return vec_splat_s16 (ui);/* { dg-error "argument 1 must be a 5-bit
> > signed literal" } */
> > +}
> > +
> > +vector unsigned short
> > +testss_2 (signed int si)
> > +{
> > + return vec_splat_u16 (si);/* { dg-error "argument 1 must be a 5-bit
> > signed literal" } */
> > +}
> > +
> > +vector signed char
> > +testsc_1 (unsigned int ui)
> > +{
> > + return vec_splat_s8 (ui); /* { dg-error "argument 1 must be a 5-bit
> > signed literal" } */
> > +}
> > +
> > +vector unsigned char
> > +testsc_2 (signed int si)
> > +{
> > + return vec_splat_u8 (si);/* { dg-error "argument 1 must be a 5-bit
> > signed literal" } */
> > +}
> > +
> >
> >
>
