[SubZero] lower float and double constants for MIPS

src/IceTargetLoweringMIPS32.h

Index: src/IceTargetLoweringMIPS32.h
diff --git a/src/IceTargetLoweringMIPS32.h b/src/IceTargetLoweringMIPS32.h
index 5cc412f2ad290bb27adcff09cc36b0c1945bf127..3fed11c4c116daea727698b5c39ab57b4b8e4488 100644
--- a/src/IceTargetLoweringMIPS32.h
+++ b/src/IceTargetLoweringMIPS32.h
@@ -38,8 +38,9 @@ public:
     if (auto *ConstDouble = llvm::dyn_cast<ConstantDouble>(C)) {
       return !Utils::isPositiveZero(ConstDouble->getValue());
     }
-    if (llvm::isa<ConstantFloat>(C))
-      return true;
+    if (auto *ConstFloat = llvm::dyn_cast<ConstantFloat>(C)) {
+      return !Utils::isPositiveZero(ConstFloat->getValue());
+    }
     return false;
   }
   static std::unique_ptr<::Ice::TargetLowering> create(Cfg *Func) {
@@ -824,7 +825,6 @@ protected:
 
 private:
   ~TargetDataMIPS32() override = default;
-  template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
 class TargetHeaderMIPS32 final : public TargetHeaderLowering {