The difference between v1 and v2 is the compact mask generation:
v1 :
+rtx
+rvv_builder::compact_mask () const
+{
+ /* Use the container mode with SEW = 8 and LMUL = 1. */
+ unsigned container_size
+ = MAX (CEIL (npatterns (), 8), BYTES_PER_RISCV_VECTOR.to_constant () / 8);
+ machine_mode container_mode
+ = get_vector_mode (QImode, container_size).require ();...
v2:
+rtx
+rvv_builder::get_compact_mask () const
+{
+ /* If TARGET_MIN_VLEN == 32, the minimum LMUL = 1/4.
+ Otherwise, the minimum LMUL = 1/8. */
+ unsigned min_lmul = TARGET_MIN_VLEN == 32 ? 4 : 8;
+ unsigned min_container_size
+ = BYTES_PER_RISCV_VECTOR.to_constant () / min_lmul;
+ unsigned container_size = MAX (CEIL (npatterns (), 8), min_container_size);
+ machine_mode container_mode
+ = get_vector_mode (QImode, container_size).require ();...
The difference is that v1:
unsigned container_size = MAX (CEIL (npatterns (), 8),
BYTES_PER_RISCV_VECTOR.to_constant () / 8);
v2:
+ /* If TARGET_MIN_VLEN == 32, the minimum LMUL = 1/4.
+ Otherwise, the minimum LMUL = 1/8. */
+ unsigned min_lmul = TARGET_MIN_VLEN == 32 ? 4 : 8;
+ unsigned min_container_size
+ = BYTES_PER_RISCV_VECTOR.to_constant () / min_lmul;
+ unsigned container_size = MAX (CEIL (npatterns (), 8), min_container_size);
[email protected]
From: Kito Cheng
Date: 2023-06-28 14:01
To: Jeff Law
CC: [email protected]; gcc-patches; kito.cheng; palmer; palmer; Robin Dapp
Subject: Re: [PATCH V2] RISC-V: Fix bug of pre-calculated const vector mask
I mean the difference between v1 and v2 patch
On Wed, Jun 28, 2023 at 12:09 PM Jeff Law <[email protected]> wrote:
>
>
>
> On 6/27/23 21:16, Kito Cheng wrote:
> > Do you mind giving some comments about what the difference between the
> > two versions?
> And I'd like a before/after assembly code with the example in the commit
> message. I didn't see the same behavior when I tried it earlier today
> and ran out of time to dig into it further.
>
> Juzhe -- most folks wait ~1wk to ping patches, even codegen bugfixes.
> Pinging this fast runs the risk of irritating others. Please be patient.
>
> Jeff
