Implements simple returns and call args for Mips.

src/IceRegistersMIPS32.h

Index: src/IceRegistersMIPS32.h
diff --git a/src/IceRegistersMIPS32.h b/src/IceRegistersMIPS32.h
index 8c75488e8e358c031c5d7c649626e61856223c4b..e8e3221fdf38c0564b93b40584b8a5823143b08f 100644
--- a/src/IceRegistersMIPS32.h
+++ b/src/IceRegistersMIPS32.h
@@ -27,7 +27,8 @@ namespace RegMIPS32 {
 /// used to binary encode register operands in instructions.
 enum AllRegisters {
 #define X(val, encode, name, scratch, preserved, stackptr, frameptr, isInt,    \
-          isFP)                                                                \
+          isI64Pair, isFP32, isFP64, isVec128, alias_init)                     \
+                                                                               \
   val,
   REGMIPS32_TABLE
 #undef X
@@ -41,7 +42,8 @@ enum AllRegisters {
 /// to binary encode register operands in instructions.
 enum GPRRegister {
 #define X(val, encode, name, scratch, preserved, stackptr, frameptr, isInt,    \
-          isFP)                                                                \
+          isI64Pair, isFP32, isFP64, isVec128, alias_init)                     \
+                                                                               \
   Encoded_##val encode,
   REGMIPS32_GPR_TABLE
 #undef X