s390: optimize for int 64-bit operation and cleanup

src/s390/assembler-s390.cc

Index: src/s390/assembler-s390.cc
diff --git a/src/s390/assembler-s390.cc b/src/s390/assembler-s390.cc
index 19510b20aab27fc9c7e1564f85b6a9db52a0a58b..c07ef2a1baf035aecf4ab0ce09aaedd311531c1d 100644
--- a/src/s390/assembler-s390.cc
+++ b/src/s390/assembler-s390.cc
@@ -1844,18 +1844,42 @@ void Assembler::adb(DoubleRegister r1, const MemOperand& opnd) {
            opnd.offset());
 }
 
+// Add Register-Storage (LB)
+void Assembler::aeb(DoubleRegister r1, const MemOperand& opnd) {
+  rxe_form(AEB, Register::from_code(r1.code()), opnd.rx(), opnd.rb(),
+           opnd.offset());
+}
+
+// Sub Register-Storage (LB)
+void Assembler::seb(DoubleRegister r1, const MemOperand& opnd) {
+  rxe_form(SEB, Register::from_code(r1.code()), opnd.rx(), opnd.rb(),
+           opnd.offset());
+}
+
 // Divide Register-Storage (LB)
 void Assembler::ddb(DoubleRegister r1, const MemOperand& opnd) {
   rxe_form(DDB, Register::from_code(r1.code()), opnd.rx(), opnd.rb(),
            opnd.offset());
 }
 
+// Divide Register-Storage (LB)
+void Assembler::deb(DoubleRegister r1, const MemOperand& opnd) {
+  rxe_form(DEB, Register::from_code(r1.code()), opnd.rx(), opnd.rb(),
+           opnd.offset());
+}
+
 // Multiply Register-Storage (LB)
 void Assembler::mdb(DoubleRegister r1, const MemOperand& opnd) {
   rxe_form(MDB, Register::from_code(r1.code()), opnd.rb(), opnd.rx(),
            opnd.offset());
 }
 
+// Multiply Register-Storage (LB)
+void Assembler::meeb(DoubleRegister r1, const MemOperand& opnd) {
+  rxe_form(MEEB, Register::from_code(r1.code()), opnd.rb(), opnd.rx(),
+           opnd.offset());
+}
+
 // Subtract Register-Storage (LB)
 void Assembler::sdb(DoubleRegister r1, const MemOperand& opnd) {
   rxe_form(SDB, Register::from_code(r1.code()), opnd.rx(), opnd.rb(),