On 10/2/24 6:27 AM, Dusan Stojkovic wrote:
This patch is a new version of:
https://gcc.gnu.org/pipermail/gcc-patches/2024-September/662745.html
<https://gcc.gnu.org/pipermail/gcc-patches/2024-September/662745.html>
> Can you elaborate a bit on that? Rearranging the CFG shouldn't matter
> in general and relying on the specific TARGET_SFB_ALU feels overly
> specific.
> Why does the same register in the if_then_else and interfere with vsetvl?
When ce1 pass transforms CFG in the case of the conditional move, it deletes
then and else basic blocks and in their place adds the conditional move
which
uses the same pseudo-register as the original vsetvl.
This interferes with vsetvl pass precisely because of the merge policy.
Use by
non rvv flag limits the cases where merging might still be possible.
This patch
tries to addresses one such issue.
Agreed. I have removed TARGET_SFB_ALU flag from the condition.
> BTW Bohan Lei has since fixed a bug regarding non-RVV uses. Does the
> situation change with that applied?
Repeated the testing for sifive-7-series as well as rocket. The same
tests are
still effected positively: vsetvlmax-9, vsetvlmax-10, vsetvlmax-11,
vsetvlmax-15
on sifive-7-series.
2024-10-2 Dusan Stojkovic <dusan.stojko...@rt-rk.com>
PR target/113035
gcc/ChangeLog:
* config/riscv/riscv-vsetvl.cc
(pre_vsetvl::earliest_fuse_vsetvl_info):
New fuse condition.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/vsetvl/vsetvlmax-15.c: Updated
scan-assembler-times num parameter.
So the meat of this patch is the introduction of this hunk of code
(formatting fixed):
if (prev_info.valid_p ()
&& curr_info.valid_p ()
&& prev_info.vl_used_by_non_rvv_insn_p ()
&& !curr_info.vl_used_by_non_rvv_insn_p ())
{
// Try to merge each demand individually
if (m_dem.sew_lmul_compatible_p (prev_info, curr_info))
m_dem.merge_sew_lmul (prev_info, curr_info);
if (m_dem.policy_compatible_p (prev_info, curr_info))
m_dem.merge_policy (prev_info, curr_info);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " After fusing curr info and "
"prev info demands individually:\n");
fprintf (dump_file, " prev_info: ");
prev_info.dump (dump_file, " ");
fprintf (dump_file, " curr_info: ");
curr_info.dump (dump_file, " ");
}
}
So why test used_by_non_rvv_insn_p here? Isn't it generally profitable
to go ahead and merge the sew/lmul and policy demands? Or does doing so
interfere with later code in this function?
Should we be setting "changed = true" when we're able to merge sew_lmul
or the merge policy?
Robin, it sounded like you had correctness concerns on the call today.
Can you expand on those?
Thanks,
Jeff
