MIPS: Don't explicitly pass requested representations to constants; implement ConstantS

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 9a99d2487885f7c8973a721fe630827f387d9fb9..8c77adccb225016c3229e40c72d40dc06777cede 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1927,11 +1927,13 @@ LInstruction* LChunkBuilder::DoReturn(HReturn* instr) {
 
 LInstruction* LChunkBuilder::DoConstant(HConstant* instr) {
   Representation r = instr->representation();
-  if (r.IsInteger32()) {
+  if (r.IsSmi()) {
+    return DefineAsRegister(new(zone()) LConstantS);
+  } else if (r.IsInteger32()) {
     return DefineAsRegister(new(zone()) LConstantI);
   } else if (r.IsDouble()) {
     return DefineAsRegister(new(zone()) LConstantD);
-  } else if (r.IsSmiOrTagged()) {
+  } else if (r.IsTagged()) {
     return DefineAsRegister(new(zone()) LConstantT);
   } else {
     UNREACHABLE();