On Thu, Oct 26, 2017 at 4:30 PM, Will Schmidt <will_schm...@vnet.ibm.com> wrote:
> 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.
Well - we of course expect to have an optab for the fma with vector
short. I thought
you had one given you have the intrinsic. If you don't have an optab
you of course
have to open-code it.
Just thought you expected an actual machine instruction doing the integer FMA.
Richard.
> 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;
>> >
>> >
>>
>
>
