[PATCH V3] SCCVN: Add LEN_MASK_STORE and fix LEN_STORE

[juzhe . zhong]

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

Hi, Richi. It seems that we use nunits which is len + bias to iterate then we 
can
simplify the codes.

Also, I fixed behavior of len_store,

Before this patch:
   (len - bias) * BITS_PER_UNIT
After this patch:
   (len + bias) * BITS_PER_UNIT
   
gcc/ChangeLog:

        * tree-ssa-sccvn.cc (vn_reference_lookup_3): Add LEN_MASK_STORE and fix 
LEN_STORE.

---
 gcc/tree-ssa-sccvn.cc | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 11061a374a2..d66e75460ed 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -3304,6 +3304,16 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void 
*data_,
          if (!tree_fits_uhwi_p (len) || !tree_fits_shwi_p (bias))
            return (void *)-1;
          break;
+       case IFN_LEN_MASK_STORE:
+         len = gimple_call_arg (call, 2);
+         bias = gimple_call_arg (call, 5);
+         if (!tree_fits_uhwi_p (len) || !tree_fits_shwi_p (bias))
+           return (void *)-1;
+         mask = gimple_call_arg (call, internal_fn_mask_index (fn));
+         mask = vn_valueize (mask);
+         if (TREE_CODE (mask) != VECTOR_CST)
+           return (void *)-1;
+         break;
        default:
          return (void *)-1;
        }
@@ -3344,6 +3354,16 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void 
*data_,
              tree vectype = TREE_TYPE (def_rhs);
              unsigned HOST_WIDE_INT elsz
                = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (vectype)));
+             poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vectype);
+             if (len)
+               {
+                 /* Since the following while condition known_lt
+                    (mask_idx, nunits) will exit the while loop
+                    when mask_idx > nunits.coeffs[0], we pick the
+                    MIN (nunits.coeffs[0], len + bias).  */
+                 nunits = MIN (nunits.coeffs[0],
+                               tree_to_uhwi (len) + tree_to_shwi (bias));
+               }
              if (mask)
                {
                  HOST_WIDE_INT start = 0, length = 0;
@@ -3373,7 +3393,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void 
*data_,
                        length += elsz;
                      mask_idx++;
                    }
-                 while (known_lt (mask_idx, TYPE_VECTOR_SUBPARTS (vectype)));
+                 while (known_lt (mask_idx, nunits));
                  if (length != 0)
                    {
                      pd.rhs_off = start;
@@ -3389,7 +3409,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void 
*data_,
                {
                  pd.offset = offset2i;
                  pd.size = (tree_to_uhwi (len)
-                            + -tree_to_shwi (bias)) * BITS_PER_UNIT;
+                            + tree_to_shwi (bias)) * BITS_PER_UNIT;
                  if (BYTES_BIG_ENDIAN)
                    pd.rhs_off = pd.size - tree_to_uhwi (TYPE_SIZE (vectype));
                  else
-- 
2.36.3