[PATCH] SSCV: Add LEN_MASK_STORE into SCCVN

[juzhe . zhong]

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

Hi, this patch is to add LEN_MASK_STORE into SCCVN.

LEN_MASK_STORE is predicated by both len and mask together.
My understanding is that LEN_MASK_STORE has same rhs_off and offset as 
MASK_STORE.
The size = MIN (length (deduced from mask), (len + bias)).

Not sure my understanding it correct or no. 
Hope experts (both Richard && Richi) can correct me if I am wrong.

Thanks.

gcc/ChangeLog:

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

---
 gcc/tree-ssa-sccvn.cc | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index 11061a374a2..d1629800705 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;
        }
@@ -3379,6 +3389,13 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void 
*data_,
                      pd.rhs_off = start;
                      pd.offset = offset2i + start;
                      pd.size = length;
+                     if (fn == IFN_LEN_MASK_STORE)
+                       {
+                         HOST_WIDE_INT len_bitsize
+                           = (tree_to_uhwi (len) + tree_to_shwi (bias))
+                             * BITS_PER_UNIT;
+                         pd.size = length > len_bitsize ? length : len_bitsize;
+                       }
                      if (ranges_known_overlap_p (offset, maxsize,
                                                  pd.offset, pd.size))
                        return data->push_partial_def (pd, set, set,
-- 
2.36.3