Re: [PATCH] RISC-V: Fix uninitialized and redundant use of which_alternative

[Patrick O'Neill <patrick@rivosinc.com>]

[-- Attachment #1: Type: text/plain, Size: 7424 bytes --]

Thanks!
Here's the comitted patch:
https://inbox.sourceware.org/gcc-patches/20230728163758.377962-1-patrick@rivosinc.com/T/#u

On 7/27/23 15:11, juzhe.zhong wrote:
> LGTM.Thanks. You can go ahead commit it.
> ---- Replied Message ----
> From 	Patrick O'Neill<patrick@rivosinc.com> <mailto:patrick@rivosinc.com>
> Date 	07/28/2023 04:46
> To 	Kito Cheng<kito.cheng@gmail.com> <mailto:kito.cheng@gmail.com>,
> juzhe.zhong@rivai.ai<juzhe.zhong@rivai.ai> <mailto:juzhe.zhong@rivai.ai>
> Cc 	demin.han<demin.han@starfivetech.com> 
> <mailto:demin.han@starfivetech.com>,
> gcc-patches<gcc-patches@gcc.gnu.org> <mailto:gcc-patches@gcc.gnu.org>
> Subject 	Re: [PATCH] RISC-V: Fix uninitialized and redundant use of 
> which_alternative
>
> The newly added testcase fails on rv32 targets with this message:
> FAIL: gcc.target/riscv/rvv/autovec/madd-split2-1.c -O3 -ftree-vectorize (test for excess errors)
>
> verbose log:
> compiler exited with status 1
> output is:
> cc1: error: ABI requires '-march=rv32'
>
> Something like this appears to fix the issue:
>
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
> b/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
> index 14a9802667e..e10a9e9d0f5 100644
> --- a/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
> @@ -1,5 +1,5 @@
>   /* { dg-do compile } */
> -/* { dg-options "-march=rv64gcv_zvl256b -O3 -fno-cprop-registers -fno-dce --param riscv-autovec-preference=scalable" } */
> +/* { dg-options "-march=rv64gcv_zvl256b -mabi=lp64d -O3
> -fno-cprop-registers -fno-dce --param riscv-autovec-preference=scalable"
>   } */
>   
>   long
>   foo (long *__restrict a, long *__restrict b, long n)
>
> On 7/27/23 04:57, Kito Cheng via Gcc-patches wrote:
>> My first impression is those emit_insn (gen_rtx_SET()) seems
>> necessary, but I got the point after I checked vector.md :P
>>
>> Committed to trunk, thanks :)
>>
>>
>> On Thu, Jul 27, 2023 at 6:23 PMjuzhe.zhong@rivai.ai
>> <juzhe.zhong@rivai.ai>  wrote:
>>> Oh, YES.
>>>
>>> Thanks for fixing it. It makes sense since the ternary operations in "vector.md"
>>> generate "vmv.v.v" according to RA.
>>>
>>> Thanks for fixing it.
>>>
>>> @kito: Could you confirm it? If it's ok to you, commit it for Han (I am lazy to commit patches :).
>>>
>>>
>>>
>>> juzhe.zhong@rivai.ai
>>>
>>> From: demin.han
>>> Date: 2023-07-27 17:48
>>> To:gcc-patches@gcc.gnu.org
>>> CC:kito.cheng@gmail.com;juzhe.zhong@rivai.ai
>>> Subject: [PATCH] RISC-V: Fix uninitialized and redundant use of which_alternative
>>> When pass split2 starts, which_alternative is random depending on
>>> last set of certain pass.
>>>
>>> Even initialized, the generated movement is redundant.
>>> The movement can be generated by assembly output template.
>>>
>>> Signed-off-by: demin.han<demin.han@starfivetech.com>
>>>
>>> gcc/ChangeLog:
>>>
>>> * config/riscv/autovec.md: Delete which_alternative use in split
>>>
>>> gcc/testsuite/ChangeLog:
>>>
>>> * gcc.target/riscv/rvv/autovec/madd-split2-1.c: New test.
>>>
>>> ---
>>> gcc/config/riscv/autovec.md                         | 12 ------------
>>> .../gcc.target/riscv/rvv/autovec/madd-split2-1.c    | 13 +++++++++++++
>>> 2 files changed, 13 insertions(+), 12 deletions(-)
>>> create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
>>>
>>> diff --git a/gcc/config/riscv/autovec.md b/gcc/config/riscv/autovec.md
>>> index d899922586a..b7ea3101f5a 100644
>>> --- a/gcc/config/riscv/autovec.md
>>> +++ b/gcc/config/riscv/autovec.md
>>> @@ -1012,8 +1012,6 @@ (define_insn_and_split "*fma<VI:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VI:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_ternary_insn (code_for_pred_mul_plus (<VI:MODE>mode),
>>>     riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> @@ -1058,8 +1056,6 @@ (define_insn_and_split "*fnma<VI:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VI:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_ternary_insn (code_for_pred_minus_mul (<VI:MODE>mode),
>>>          riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> @@ -1102,8 +1098,6 @@ (define_insn_and_split "*fma<VF:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VF:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_fp_ternary_insn (code_for_pred_mul (PLUS, <VF:MODE>mode),
>>>        riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> @@ -1148,8 +1142,6 @@ (define_insn_and_split "*fnma<VF:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VF:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_fp_ternary_insn (code_for_pred_mul_neg (PLUS, <VF:MODE>mode),
>>>        riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> @@ -1194,8 +1186,6 @@ (define_insn_and_split "*fms<VF:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VF:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_fp_ternary_insn (code_for_pred_mul (MINUS, <VF:MODE>mode),
>>>        riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> @@ -1242,8 +1232,6 @@ (define_insn_and_split "*fnms<VF:mode><P:mode>"
>>>     [(const_int 0)]
>>>     {
>>>       riscv_vector::emit_vlmax_vsetvl (<VF:MODE>mode, operands[4]);
>>> -    if (which_alternative == 2)
>>> -      emit_insn (gen_rtx_SET (operands[0], operands[3]));
>>>       rtx ops[] = {operands[0], operands[1], operands[2], operands[3], operands[0]};
>>>       riscv_vector::emit_vlmax_fp_ternary_insn (code_for_pred_mul_neg (MINUS, <VF:MODE>mode),
>>>        riscv_vector::RVV_TERNOP, ops, operands[4]);
>>> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
>>> new file mode 100644
>>> index 00000000000..14a9802667e
>>> --- /dev/null
>>> +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/madd-split2-1.c
>>> @@ -0,0 +1,13 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-march=rv64gcv_zvl256b -O3 -fno-cprop-registers -fno-dce --param riscv-autovec-preference=scalable" } */
>>> +
>>> +long
>>> +foo (long *__restrict a, long *__restrict b, long n)
>>> +{
>>> +  long i;
>>> +  for (i = 0; i < n; ++i)
>>> +    a[i] = b[i] + i * 8;
>>> +  return a[1];
>>> +}
>>> +
>>> +/* { dg-final { scan-assembler-times {\tvmv1r\.v} 1 } } */
>>> --
>>> 2.41.0
>>>
>>>