[PATCH] RISC-V: Change VSETVL PASS always call split_all_insns

[juzhe.zhong@rivai.ai]

From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>

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.

---
 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 0245124e28f..d494369a603 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -3092,12 +3092,10 @@ 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))
-- 
2.36.3