[gcc r13-5428] RISC-V: Change VSETVL PASS always call split_all_insns

[gcc r13-5428] RISC-V: Change VSETVL PASS always call split_all_insns

[Kito Cheng]

https://gcc.gnu.org/g:ca8fb0096713a8477614ef874f16ba5bf16c48bc

commit r13-5428-gca8fb0096713a8477614ef874f16ba5bf16c48bc
Author: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>
Date:   Wed Jan 18 10:50:14 2023 +0800

    RISC-V: Change VSETVL PASS always call split_all_insns
    
    Since LCM will destroy CFG, we are going to reorder the location of VSETVL PASS
    at least before bbro (block-reorder PASS) which is before split3 PASS. We need
    to call it in VSETVL PASS to get final RVV instructions patterns.
    
    gcc/ChangeLog:
    
            * config/riscv/riscv-vsetvl.cc (pass_vsetvl::execute): Always call split_all_insns.

Diff:
---
 gcc/config/riscv/riscv-vsetvl.cc | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index e4bc3d2b353..8b3fd33f558 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -3086,12 +3086,10 @@ pass_vsetvl::execute (function *)
   if (n_basic_blocks_for_fn (cfun) <= 0)
     return 0;
 
-  /* The reason we have this since we didn't finish splitting yet
-     when optimize == 0. In this case, we should conservatively
-     split all instructions here to make sure we don't miss any
-     RVV instruction.  */
-  if (!optimize)
-    split_all_insns ();
+  /* The RVV instruction may change after split which is not a stable
+     instruction. We need to split it here to avoid potential issue
+     since the VSETVL PASS is insert before split PASS.  */
+  split_all_insns ();
 
   /* Early return for there is no vector instructions.  */
   if (!has_vector_insn (cfun))