[clang] [llvm] [SystemZ] Add support for half (fp16) (PR #109164)

[Ulrich Weigand via cfe-commits]

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@@ -711,6 +711,13 @@ SystemZTargetLowering::SystemZTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::BITCAST, MVT::f32, Custom);
   }
 
+  // Expand FP16 <=> FP32 conversions to libcalls and handle FP16 loads and
+  // stores in GPRs.
+  setOperationAction(ISD::FP16_TO_FP, MVT::f32, Expand);
+  setOperationAction(ISD::FP_TO_FP16, MVT::f32, Expand);
+  setLoadExtAction(ISD::EXTLOAD, MVT::f32, MVT::f16, Expand);
+  setTruncStoreAction(MVT::f32, MVT::f16, Expand);
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uweigand wrote:

Do we need to support *both* the conversion operations *and* the truncate/extend?

https://github.com/llvm/llvm-project/pull/109164