The powers that be have decided that LLVM IR should now support 16-bit
"half precision" floating-point with a first-class type.

This patch adds basic IR support (but not codegen support).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146786 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 46e4acd..49a498f 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1160,6 +1160,9 @@
   if (ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
     if (CFP->getType() == Type::getPPC_FP128Ty(V->getContext()))
       return V;  // No constant folding of this.
+    // See if the value can be truncated to half and then reextended.
+    if (Value *V = FitsInFPType(CFP, APFloat::IEEEhalf))
+      return V;
     // See if the value can be truncated to float and then reextended.
     if (Value *V = FitsInFPType(CFP, APFloat::IEEEsingle))
       return V;