I think we should leave it to user choice.
--param=riscv-autovec-lmul=m1/m2/m4/m8/dynamic.
So use TARGET_MAX_LMUL should be more reasonable.
juzhe.zh...@rivai.ai
From: Sergei Lewis
Date: 2023-12-11 22:58
To: juzhe.zh...@rivai.ai
CC: gcc-patches; Robin Dapp; Kito.cheng; jeffreyalaw
Subject: Re: [PATCH 2/3] RISC-V: setmem for RISCV with V extension
The thinking here is that using the largest possible LMUL when we know the
operation will fit in fewer registers potentially leaves performance on the
table - indirectly, due to the unnecessarily increased register pressure, and
also directly, depending on the implementation.
On Mon, Dec 11, 2023 at 10:05 AM juzhe.zh...@rivai.ai <juzhe.zh...@rivai.ai>
wrote:
Hi, Thanks for contributing this.
+/* Select appropriate LMUL for a single vector operation based on
+ byte size of data to be processed.
+ On success, return true and populate lmul_out.
+ If length_in is too wide for a single vector operation, return false
+ and leave lmul_out unchanged. */
+
+static bool
+select_appropriate_lmul (HOST_WIDE_INT length_in,
+ HOST_WIDE_INT &lmul_out)
+{
I don't think we need this, you only need to use TARGET_MAX_LMUL
juzhe.zh...@rivai.ai
