Address all comments on V2 patch:
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625038.html 

Redundant vsetvli are elided by this code:
  rtx len = type == reduction_type::MASK_LEN_FOLD_LEFT ? ops[4] : NULL_RTX;
  emit_scalar_move_insn (code_for_pred_broadcast (m1_mode), scalar_move_ops,
                         len);

Pass through len operand for MASK_LEN_FOLD_LEFT

Now the codegen:

foo:
lui a5,%hi(.LC0)
flw fa0,%lo(.LC0)(a5)
ble a1,zero,.L4
.L3:
vsetvli a5,a1,e32,m1,ta,ma
slli a4,a5,2
sub a1,a1,a5
vle32.v v1,0(a0)
vfmv.s.f v2,fa0
add a0,a0,a4
vfredosum.vs v1,v1,v2
vfmv.f.s fa0,v1
bne a1,zero,.L3
ret


juzhe.zhong@rivai.ai
 
From: Kito Cheng
Date: 2023-07-20 16:24
To: juzhe.zhong@rivai.ai
CC: Robin Dapp; gcc-patches; kito.cheng; jeffreyalaw
Subject: Re: Re: [PATCH] RISC-V: Support in-order floating-point reduction
reduction_type = reduction_type::UNORDERED
 
On Thu, Jul 20, 2023 at 4:16 PM juzhe.zhong@rivai.ai
<juzhe.zhong@rivai.ai> wrote:
>
> I have tried this:
> enum class reduction_type
> {
>   UNORDERED,
>   FOLD_LEFT,
>   MASK_LEN_FOLD_LEFT,
> };
>
> But fail to build.....
>
> /gcc/build -I../../../riscv-gcc/gcc/../include  -I../../../riscv-gcc/gcc/../libcpp/include -g -O0 \
>         -o build/gencondmd.o build/gencondmd.cc
> In file included from ./tm_p.h:4:0,
>                  from build/gencondmd.cc:29:
> ../../../riscv-gcc/gcc/config/riscv/riscv-protos.h:294:36: error: could not convert ‘UNORDERED’ from ‘rtx_code’ to ‘riscv_vector::reduction_type’
>           reduction_type = UNORDERED);
>
> ________________________________
> juzhe.zhong@rivai.ai
>
>
> From: Kito Cheng
> Date: 2023-07-20 16:03
> To: juzhe.zhong@rivai.ai
> CC: Robin Dapp; gcc-patches; kito.cheng; jeffreyalaw
> Subject: Re: Re: [PATCH] RISC-V: Support in-order floating-point reduction
> Seems like because you ` using namespace riscv_vector;` so the
> UNORDERED in expand_vec_cmp_float used reduction_type::UNORDERED
>
> Hmmm, maybe enum class?
>
> enum class reduction_type
> {
>   UNORDERED,
>   FOLD_LEFT,
>   MASK_LEN_FOLD_LEFT,
> };
>
> and need use like this reduction_type::UNORDERED
>
> On Thu, Jul 20, 2023 at 3:59 PM juzhe.zhong@rivai.ai
> <juzhe.zhong@rivai.ai> wrote:
> >
> > I have no ideal, just ICE comes when running regression:
> >
> > during RTL pass: expand
> > auto.c: In function 'test_int32_t_float_unordered_var':
> > auto.c:24:3: internal compiler error: in expand_vec_cmp_float, at config/riscv/riscv-v.cc:2564
> >    24 |   test_##TYPE1##_##TYPE2##_##CMP##_var (TYPE1 *restrict dest,   \
> >       |   ^~~~~
> > auto.c:41:3: note: in expansion of macro 'TEST_LOOP'
> >    41 |   TEST_LOOP (int32_t, float, CMP) \
> >       |   ^~~~~~~~~
> > auto.c:55:1: note: in expansion of macro 'TEST_CMP'
> >    55 | TEST_CMP (unordered)
> >       | ^~~~~~~~
> > 0x1c8af0d riscv_vector::expand_vec_cmp_float(rtx_def*, rtx_code, rtx_def*, rtx_def*, bool)
> >         ../../../riscv-gcc/gcc/config/riscv/riscv-v.cc:2564
> > 0x233d200 gen_vec_cmprvvm1sfrvvmf32bi(rtx_def*, rtx_def*, rtx_def*, rtx_def*)
> >         ../../../riscv-gcc/gcc/config/riscv/autovec.md:559
> > 0x14c4582 rtx_insn* insn_gen_fn::operator()<rtx_def*, rtx_def*, rtx_def*, rtx_def*>(rtx_def*, rtx_def*, rtx_def*, rtx_def*) const
> >         ../../../riscv-gcc/gcc/recog.h:407
> > 0x14c3c02 maybe_gen_insn(insn_code, unsigned int, expand_operand*)
> >         ../../../riscv-gcc/gcc/optabs.cc:8197
> > 0x14c4097 maybe_expand_insn(insn_code, unsigned int, expand_operand*)
> >         ../../../riscv-gcc/gcc/optabs.cc:8237
> > 0x14c412b expand_insn(insn_code, unsigned int, expand_operand*)
> >         ../../../riscv-gcc/gcc/optabs.cc:8268
> > 0x14bfc3e expand_vec_cmp_expr(tree_node*, tree_node*, rtx_def*)
> >         ../../../riscv-gcc/gcc/optabs.cc:6692
> > 0x1124e4a do_store_flag
> >         ../../../riscv-gcc/gcc/expr.cc:13060
> > 0x1116b10 expand_expr_real_2(separate_ops*, rtx_def*, machine_mode, expand_modifier)
> >         ../../../riscv-gcc/gcc/expr.cc:10265
> > 0x1119405 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, expand_modifier, rtx_def**, bool)
> >         ../../../riscv-gcc/gcc/expr.cc:10810
> > 0x1110fb0 expand_expr_real(tree_node*, rtx_def*, machine_mode, expand_modifier, rtx_def**, bool)
> >         ../../../riscv-gcc/gcc/expr.cc:9015
> > 0xf2e973 expand_normal(tree_node*)
> >         ../../../riscv-gcc/gcc/expr.h:316
> > 0x12bb060 expand_vec_cond_mask_optab_fn
> >         ../../../riscv-gcc/gcc/internal-fn.cc:3059
> > 0x12c27ca expand_VCOND_MASK
> >         ../../../riscv-gcc/gcc/internal-fn.def:184
> > 0x12c52a5 expand_internal_call(internal_fn, gcall*)
> >         ../../../riscv-gcc/gcc/internal-fn.cc:4792
> > 0x12c52d0 expand_internal_call(gcall*)
> >         ../../../riscv-gcc/gcc/internal-fn.cc:4800
> > 0xf5e4c1 expand_call_stmt
> >         ../../../riscv-gcc/gcc/cfgexpand.cc:2737
> > 0xf62871 expand_gimple_stmt_1
> >         ../../../riscv-gcc/gcc/cfgexpand.cc:3880
> > 0xf62f0f expand_gimple_stmt
> >         ../../../riscv-gcc/gcc/cfgexpand.cc:4044
> > 0xf6b8a9 expand_gimple_basic_block
> >         ../../../riscv-gcc/gcc/cfgexpand.cc:6096
> >
> > This ICE happens when compiling vcond.cc tests
> > ________________________________
> > juzhe.zhong@rivai.ai
> >
> >
> > From: Robin Dapp
> > Date: 2023-07-20 15:57
> > To: juzhe.zhong@rivai.ai; gcc-patches
> > CC: rdapp.gcc; kito.cheng; Kito.cheng; jeffreyalaw
> > Subject: Re: [PATCH] RISC-V: Support in-order floating-point reduction
> > > The UNORDERED enum will cause ICE since we have UNORDERED in rtx_code.
> > >
> > > Could you give me another enum name?
> >
> > I would have expected it to work when it's namespaced.
> >
> > Regards
> > Robin
> >
> >
>