[PATCH] RISC-V: Fix incorrect implementation of TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT

[juzhe . zhong]

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

This incorrect codes blocks the scalable RVV auto-vectorization.
Take a look at this target hook implementation of aarch64.
They only have the similiar handling on TARGET_SIMD.

They let movmisalign<mode> to handle scalable vector of SVE.
For RVV, we should follow the same implementation of ARM SVE.

gcc/ChangeLog:

        * config/riscv/riscv.cc (riscv_support_vector_misalignment): Fix 
incorrect codes.

---
 gcc/config/riscv/riscv.cc | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 8684271f8ac..ff90c44d811 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -7264,27 +7264,20 @@ riscv_estimated_poly_value (poly_int64 val,
   return val.coeffs[0] + val.coeffs[1] * over_128 / 128;
 }
 
+/* Return true if the vector misalignment factor is supported by the
+   target.  */
 bool
 riscv_support_vector_misalignment (machine_mode mode,
                                   const_tree type ATTRIBUTE_UNUSED,
                                   int misalignment,
                                   bool is_packed ATTRIBUTE_UNUSED)
 {
-  if (TARGET_VECTOR)
-    {
-      if (STRICT_ALIGNMENT)
-       {
-         /* Return if movmisalign pattern is not supported for this mode.  */
-         if (optab_handler (movmisalign_optab, mode) == CODE_FOR_nothing)
-           return false;
-
-         /* Misalignment factor is unknown at compile time.  */
-         if (misalignment == -1)
-           return false;
-       }
-      return true;
-    }
+  /* TODO: For RVV scalable vector auto-vectorization, we should allow
+     movmisalign<mode> pattern to handle misalign data movement to unblock
+     possible auto-vectorization.
 
+     RVV VLS auto-vectorization or SIMD auto-vectorization can be supported 
here
+     in the future.  */
   return default_builtin_support_vector_misalignment (mode, type, misalignment,
                                                      is_packed);
 }
-- 
2.36.3