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

[Jonas Paulsson via cfe-commits]

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@@ -6769,11 +6898,20 @@ SystemZTargetLowering::LowerOperationWrapper(SDNode *N,
     break;
   }
   case ISD::BITCAST: {
+    SDLoc DL(N);
     SDValue Src = N->getOperand(0);
-    if (N->getValueType(0) == MVT::i128 && Src.getValueType() == MVT::f128 &&
-        !useSoftFloat()) {
-      SDLoc DL(N);
+    EVT SrcVT = Src.getValueType();
+    EVT ResVT = N->getValueType(0);
+    if (ResVT == MVT::i128 && SrcVT == MVT::f128 && !useSoftFloat())
       Results.push_back(expandBitCastF128ToI128(DAG, Src, DL));
+    else if (SrcVT == MVT::i16 && ResVT == MVT::f16) {
+      SDValue In32 = DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i32, Src);
+      Results.push_back(
+          SDValue(DAG.getMachineNode(SystemZ::LEFR_16, DL, MVT::f16, In32), 0));
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JonPsson1 wrote:

Bitcast without vector via mem.
BITCAST handling is needed AFAIK for IR bitcast instructions, and also for inline assembly that e.g. uses an 'f' constraint while passing an i16 value.
Seems to be working according to added tests.

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