diff --git a/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp b/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
--- a/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Numeric.cpp
@@ -11,6 +11,7 @@
 #include "flang/Optimizer/Builder/Character.h"
 #include "flang/Optimizer/Builder/FIRBuilder.h"
 #include "flang/Optimizer/Builder/Runtime/RTBuilder.h"
+#include "flang/Optimizer/Builder/Todo.h"
 #include "flang/Runtime/numeric.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
 
@@ -212,7 +213,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32()) {
+  if (fltTy.isF16()) {
+    TODO(loc, "support for REAL with KIND = 2 in EXPONENT");
+  } else if (fltTy.isF32()) {
     if (resultType.isInteger(32))
       func = fir::runtime::getRuntimeFunc<mkRTKey(Exponent4_4)>(loc, builder);
     else if (resultType.isInteger(64))
@@ -233,7 +236,7 @@
     else if (resultType.isInteger(64))
       func = fir::runtime::getRuntimeFunc<ForcedExponent16_8>(loc, builder);
   } else
-    fir::emitFatalError(loc, "unsupported real kind in Exponent lowering");
+    fir::emitFatalError(loc, "unsupported REAL KIND in EXPONENT");
 
   auto funcTy = func.getFunctionType();
   llvm::SmallVector<mlir::Value> args = {
@@ -247,8 +250,9 @@
                                       mlir::Location loc, mlir::Value x) {
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
-
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in FRACTION");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Fraction4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Fraction8)>(loc, builder);
@@ -257,7 +261,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedFraction16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported real kind in Fraction lowering");
+    fir::emitFatalError(loc, "unsupported real kind in FRACTION");
 
   auto funcTy = func.getFunctionType();
   llvm::SmallVector<mlir::Value> args = {
@@ -273,7 +277,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in NEAREST");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Nearest4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Nearest8)>(loc, builder);
@@ -282,7 +288,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedNearest16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported REAL kind in Nearest lowering");
+    fir::emitFatalError(loc, "unsupported REAL kind in NEAREST");
 
   auto funcTy = func.getFunctionType();
 
@@ -308,7 +314,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in RRSPACING");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(RRSpacing4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(RRSpacing8)>(loc, builder);
@@ -317,7 +325,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedRRSpacing16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported real kind in RRSpacing lowering");
+    fir::emitFatalError(loc, "unsupported real kind in RRSPACING");
 
   auto funcTy = func.getFunctionType();
   llvm::SmallVector<mlir::Value> args = {
@@ -333,7 +341,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in SCALE");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Scale4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Scale8)>(loc, builder);
@@ -342,7 +352,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedScale16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported REAL kind in Scale lowering");
+    fir::emitFatalError(loc, "unsupported REAL kind in SCALE");
 
   auto funcTy = func.getFunctionType();
   auto args = fir::runtime::createArguments(builder, loc, funcTy, x, i);
@@ -357,7 +367,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in FRACTION");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(SetExponent4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(SetExponent8)>(loc, builder);
@@ -366,7 +378,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedSetExponent16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported real kind in Fraction lowering");
+    fir::emitFatalError(loc, "unsupported real kind in FRACTION");
 
   auto funcTy = func.getFunctionType();
   auto args = fir::runtime::createArguments(builder, loc, funcTy, x, i);
@@ -380,7 +392,9 @@
   mlir::func::FuncOp func;
   mlir::Type fltTy = x.getType();
 
-  if (fltTy.isF32())
+  if (fltTy.isF16())
+    TODO(loc, "support for REAL with KIND = 2 in SPACING");
+  else if (fltTy.isF32())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Spacing4)>(loc, builder);
   else if (fltTy.isF64())
     func = fir::runtime::getRuntimeFunc<mkRTKey(Spacing8)>(loc, builder);
@@ -389,7 +403,7 @@
   else if (fltTy.isF128())
     func = fir::runtime::getRuntimeFunc<ForcedSpacing16>(loc, builder);
   else
-    fir::emitFatalError(loc, "unsupported real kind in Spacing lowering");
+    fir::emitFatalError(loc, "unsupported real kind in SPACING");
 
   auto funcTy = func.getFunctionType();
   llvm::SmallVector<mlir::Value> args = {