[jdk16] RFR: 8260339: JVM crashes when executing PhaseIdealLoop::match_fill_loop

[Wang Huang]

The reason is :

  BasicType t = store->as_Mem()->memory_type();
  const char* fill_name;
  if (msg == NULL &&
      StubRoutines::select_fill_function(t, false, fill_name) == NULL) {
    msg = "unsupported store";
    msg_node = store;
  }

If the `store` is a `StoreVectorNode` ,the `BasicType` is `T_VOID`. We should get the basic type from `vect_type()->element_basic_type()` .

- BasicType t = store->as_Mem()->memory_type();
+ BasicType t;
+ if (store->is_StoreVector()) {
+ t = store->as_StoreVector()->vect_type()->element_basic_type();
+ } else {
+ t = store->as_Mem()->memory_type();
+ }

-------------

Commit messages:
 - fix code style after if
 - 8260339: JVM crashes when executing PhaseIdealLoop::match_fill_loop

Changes: https://git.openjdk.java.net/jdk16/pull/132/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16&pr=132&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260339
  Stats: 6 lines in 1 file changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/132.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/132/head:pull/132

PR: https://git.openjdk.java.net/jdk16/pull/132