8372641: [s390x] Test failure TestMergeStores.java

Reviewed-by: mhaessig, amitkumar, lucy

Author: Harshit470250

src/hotspot/cpu/s390/s390.ad

@@ -1715,6 +1715,8 @@ bool Matcher::match_rule_supported(int opcode) {
   switch (opcode) {
     case Op_ReverseBytesI:
     case Op_ReverseBytesL:
+    case Op_ReverseBytesS:
+    case Op_ReverseBytesUS:
       return UseByteReverseInstruction;
     case Op_PopCountI:
     case Op_PopCountL:
@@ -11615,6 +11617,38 @@ instruct vround2D_reg(vecX dst, vecX src, immI8 rmode) %{
 
 // Byte reverse
 
+instruct bytes_reverse_short(iRegI dst, iRegI src) %{
+  match(Set dst (ReverseBytesS src));
+  predicate(UseByteReverseInstruction);
+  ins_cost(2 * DEFAULT_COST);
+  size(8);
+
+  format %{ "LRVR   $dst, $src\n\t # byte reverse int"
+            "SRA    $dst, 0x0010\t # right shift by 16, sign extended" %}
+
+  ins_encode %{
+    __ z_lrvr($dst$$Register, $src$$Register);
+    __ z_sra($dst$$Register, 0x0010);
+  %}
+  ins_pipe(pipe_class_dummy);
+%}
+
+instruct bytes_reverse_unsigned_short(iRegI dst, iRegI src) %{
+  match(Set dst (ReverseBytesUS src));
+  predicate(UseByteReverseInstruction);
+  ins_cost(2 * DEFAULT_COST);
+  size(8);
+
+  format %{ "LRVR   $dst, $src\n\t # byte reverse int"
+            "SRL    $dst, 0x0010\t # right shift by 16, zero extended" %}
+
+  ins_encode %{
+    __ z_lrvr($dst$$Register, $src$$Register);
+    __ z_srl($dst$$Register, 0x0010);
+  %}
+  ins_pipe(pipe_class_dummy);
+%}
+
 instruct bytes_reverse_int(iRegI dst, iRegI src) %{
   match(Set dst (ReverseBytesI src));
   predicate(UseByteReverseInstruction);  // See Matcher::match_rule_supported