Reland: Add unoptimized/optimized variants of MathFloor TF code stub

src/mips64/interface-descriptors-mips64.cc

Index: src/mips64/interface-descriptors-mips64.cc
diff --git a/src/mips64/interface-descriptors-mips64.cc b/src/mips64/interface-descriptors-mips64.cc
index 689bbbb9ee392cf13160ebffb6b1417251cbaacd..47cc0923cb8f0b7009fededac3770740c295372a 100644
--- a/src/mips64/interface-descriptors-mips64.cc
+++ b/src/mips64/interface-descriptors-mips64.cc
@@ -330,11 +330,22 @@ void ApiAccessorDescriptor::InitializePlatformSpecific(
 }
 
 
-void MathRoundVariantDescriptor::InitializePlatformSpecific(
-    CallInterfaceDescriptorData* data) {
+void MathRoundVariantCallFromUnoptimizedCodeDescriptor::
+    InitializePlatformSpecific(CallInterfaceDescriptorData* data) {
+  Register registers[] = {
+      a1,  // math rounding function
+      a3,  // vector slot id
+  };
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+
+void MathRoundVariantCallFromOptimizedCodeDescriptor::
+    InitializePlatformSpecific(CallInterfaceDescriptorData* data) {
   Register registers[] = {
       a1,  // math rounding function
       a3,  // vector slot id
+      a2,  // type vector
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }