> Could we instead do something like:
>
> diff --git a/gcc/expmed.cc b/gcc/expmed.cc
> index 13803c6bbd0..c6494484251 100644
> --- a/gcc/expmed.cc
> +++ b/gcc/expmed.cc
> @@ -2022,14 +2022,16 @@ extract_integral_bit_field (rtx op0,
> opt_scalar_int_mode op0_mode,
> (unsignedp ? 1 : -1), target_part,
> mode, word_mode, reverse, fallback_p, NULL);
>
> - gcc_assert (target_part);
> if (!result_part)
> {
> delete_insns_since (last);
> return NULL;
> }
>
> - if (result_part != target_part)
> + if (!target_part)
> + store_bit_field (target, BITS_PER_WORD, i * BITS_PER_WORD,
> + 0, 0, word_mode, result_part, false, i == 0);
> + else if (result_part != target_part)
> emit_move_insn (target_part, result_part);
> }
>
> It fixes the ICE but I haven't tested beyond that.
This is almost exactly what I had initially until I realized the
operand_subword in the if (unsignedp). Even though I didn't manage to
trigger it, it looked vulnerable. But if you're OK with the above,
I'll go ahead with that. It's even bootstrapped and regtested already
:)
>> diff --git a/gcc/testsuite/g++.target/riscv/rvv/autovec/pr127323.C
>> b/gcc/testsuite/g++.target/riscv/rvv/autovec/pr127323.C
>> new file mode 100644
>> index 00000000000..3809d81b6fe
>> --- /dev/null
>> +++ b/gcc/testsuite/g++.target/riscv/rvv/autovec/pr127323.C
>> @@ -0,0 +1,39 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-O3 -mrvv-max-lmul=conv-dynamic -march=rv64gcv -mabi=lp64d
>> -mvector-strict-align" } */
>
> For me the ICE only triggered with -mtune=generic-ooo, as in the PR.
Yes, and that's due to a riscv target issue. Our
riscv_slow_unaligned_access is currently wrong and sends generic-ooo the
"unsupported" way even though it should do the opposite.
I think, strictly, this particular ICE wouldn't even happen anymore
after fixing riscv_slow_unaligned_access, regardless of the option.
We aren't going to see element-misaligned vectors here and only those
are unsupported.
So yeah, I guess the test is then misleading at best. Maybe I should
even drop the patch then, as we won't hit this particular case right
now? It's still wrong as written I guess.
--
Regards
Robin
