X87: Emit memory operands for cmp and test on ia32 and x64 when it makes sense.

src/x87/assembler-x87.cc

Index: src/x87/assembler-x87.cc
diff --git a/src/x87/assembler-x87.cc b/src/x87/assembler-x87.cc
index 53919486d667ff7c63f1965c635fb7d6c37dbbe5..66fda5787f99b12a5a15a2f7c9c431659bcc4b3d 100644
--- a/src/x87/assembler-x87.cc
+++ b/src/x87/assembler-x87.cc
@@ -674,6 +674,11 @@ void Assembler::cmp(Register reg, const Operand& op) {
   emit_operand(reg, op);
 }
 
+void Assembler::cmp(const Operand& op, Register reg) {
+  EnsureSpace ensure_space(this);
+  EMIT(0x39);
+  emit_operand(reg, op);
+}
 
 void Assembler::cmp(const Operand& op, const Immediate& imm) {
   EnsureSpace ensure_space(this);