On Thu, 2017-10-26 at 11:05 +0200, Richard Biener wrote:
> On Wed, Oct 25, 2017 at 4:38 PM, Will Schmidt <will_schm...@vnet.ibm.com>
> wrote:
> > Hi,
> >
> > Add support for gimple folding of the vec_madd() (vector multiply-add)
> > intrinsics.
> > Testcase coverage is provided by the existing tests
> > gcc.target/powerpc/fold-vec-madd-*.c
> >
> > Sniff-tests appear clean. A full regtest is currently running across
> > assorted Power systems. (P6-P9).
> > OK for trunk (pending clean run results)?
>
> You can use FMA_EXPR on integer operands as well. Otherwise you risk
> the FMA be not matched by combine later when part of the operation is
> CSEd.
I had tried that initially, without success,.. I'll probably need
another hint. :-)
Looking a bit closer, I think I see why the assert fired, but I'm not
sure what the proper fix would be.
So attempting to the FMA_EXPR on the integer operands. (vector shorts in
this case), I end up triggering this error:
/home/willschm/gcc/gcc-mainline-vec_fold_misc/gcc/testsuite/gcc.target/powerpc/fold-vec-madd-short.c:14:10:
internal compiler error: in expand_expr_real_2, at expr.c:8712
0x10813303 expand_expr_real_2(separate_ops*, rtx_def*, machine_mode,
expand_modifier)
/home/willschm/gcc/gcc-mainline-vec_fold_misc/gcc/expr.c:8712
0x1081822f expand_expr_real_1(tree_node*, rtx_def*, machine_mode,
expand_modifier, rtx_def**, bool)
/home/willschm/gcc/gcc-mainline-vec_fold_misc/gcc/expr.c:9787
0x1080f7bb expand_expr_real(tree_node*, rtx_def*, machine_mode,
expand_modifier, rtx_def**, bool)
/home/willschm/gcc/gcc-mainline-vec_fold_misc/gcc/expr.c:8084
...
which when followed back, I tripped an assert here: (gcc/expr.c:
expand_expr_real_2() ~ line 8710)
case FMA_EXPR:
{
optab opt = fma_optab;
gimple *def0, *def2;
if (optab_handler (fma_optab, mode) == CODE_FOR_nothing)
{
tree fn = mathfn_built_in (TREE_TYPE (treeop0), BUILT_IN_FMA);
tree call_expr;
gcc_assert (fn != NULL_TREE);
where gcc/builtins.c
mathfn_built_in()->mathfn_built_in_1->mathfn_built_in_2 looks to have
returned END_BUILTINS/NULL_TREE, due to falling through the if/else
tree:
if (TYPE_MAIN_VARIANT (type) == double_type_node)
return fcode;
else if (TYPE_MAIN_VARIANT (type) == float_type_node)
return fcodef;
else if (TYPE_MAIN_VARIANT (type) == long_double_type_node)
return fcodel;
else
return END_BUILTINS;
Looks like that is all double/float/long double contents. First blush
attempt would be to add V8HI_type_node/integer_type_node to that if/else
tree, but that doesn't look like it would be near enough.
Thanks
-Will
>
> Richard.
>
> > Thanks,
> > -Will
> >
> > [gcc]
> >
> > 2017-10-25 Will Schmidt <will_schm...@vnet.ibm.com>
> >
> > * config/rs6000/rs6000.c: (rs6000_gimple_fold_builtin) Add support
> > for
> > gimple folding of vec_madd() intrinsics.
> >
> > diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> > index 4837e14..04c2b15 100644
> > --- a/gcc/config/rs6000/rs6000.c
> > +++ b/gcc/config/rs6000/rs6000.c
> > @@ -16606,10 +16606,43 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator
> > *gsi)
> > build_int_cst (arg2_type, 0)),
> > arg0);
> > gimple_set_location (g, loc);
> > gsi_replace (gsi, g, true);
> > return true;
> > }
> > +
> > + /* vec_madd (Float) */
> > + case ALTIVEC_BUILTIN_VMADDFP:
> > + case VSX_BUILTIN_XVMADDDP:
> > + {
> > + arg0 = gimple_call_arg (stmt, 0);
> > + arg1 = gimple_call_arg (stmt, 1);
> > + tree arg2 = gimple_call_arg (stmt, 2);
> > + lhs = gimple_call_lhs (stmt);
> > + gimple *g = gimple_build_assign (lhs, FMA_EXPR , arg0, arg1, arg2);
> > + gimple_set_location (g, gimple_location (stmt));
> > + gsi_replace (gsi, g, true);
> > + return true;
> > + }
> > + /* vec_madd (Integral) */
> > + case ALTIVEC_BUILTIN_VMLADDUHM:
> > + {
> > + arg0 = gimple_call_arg (stmt, 0);
> > + arg1 = gimple_call_arg (stmt, 1);
> > + tree arg2 = gimple_call_arg (stmt, 2);
> > + lhs = gimple_call_lhs (stmt);
> > + tree lhs_type = TREE_TYPE (lhs);
> > + location_t loc = gimple_location (stmt);
> > + gimple_seq stmts = NULL;
> > + tree mult_result = gimple_build (&stmts, loc, MULT_EXPR,
> > + lhs_type, arg0, arg1);
> > + tree plus_result = gimple_build (&stmts, loc, PLUS_EXPR,
> > + lhs_type, mult_result, arg2);
> > + gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
> > + update_call_from_tree (gsi, plus_result);
> > + 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;
> >
> >
>
