[PATCH] RISC-V: Fix PR109535

[juzhe . zhong]

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

gcc/ChangeLog:

        * config/riscv/riscv-vsetvl.cc (count_regno_occurrences): New function.
        (pass_vsetvl::cleanup_insns): Fix bug.

---
 gcc/config/riscv/riscv-vsetvl.cc | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
index 1b66e3b9eeb..43e2cf08377 100644
--- a/gcc/config/riscv/riscv-vsetvl.cc
+++ b/gcc/config/riscv/riscv-vsetvl.cc
@@ -1592,6 +1592,19 @@ backward_propagate_worthwhile_p (const basic_block 
cfg_bb,
   return true;
 }
 
+/* Count the number of REGNO in RINSN.  */
+int
+count_regno_occurrences (rtx_insn *rinsn, unsigned int regno)
+{
+  int count = 0;
+  extract_insn (rinsn);
+  for (int i = 0; i < recog_data.n_operands; i++)
+    if (REG_P (recog_data.operand[i])
+       && REGNO (recog_data.operand[i]) == regno)
+      count++;
+  return count;
+}
+
 avl_info::avl_info (const avl_info &other)
 {
   m_value = other.get_value ();
@@ -3924,7 +3937,7 @@ pass_vsetvl::cleanup_insns (void) const
          if (!has_vl_op (rinsn) || !REG_P (get_vl (rinsn)))
            continue;
          rtx avl = get_vl (rinsn);
-         if (count_occurrences (PATTERN (rinsn), avl, 0) == 1)
+         if (count_regno_occurrences (rinsn, REGNO (avl)) == 1)
            {
              /* Get the list of uses for the new instruction.  */
              auto attempt = crtl->ssa->new_change_attempt ();
-- 
2.36.3