AMDGPU: During img instruction ret value construction cater for non int values

[dstuttard]

Summary

Make sure return type is int type.

Change-Id: I5b2076fd027bd1b0bd2c3494184a278eb04a538f

[dstuttard]

We ran across this issue a while back for graphics, but I'd forgotten to upstream it.

[arsenm]

Missing test?

[Joe_Nash]

In D108131#2949244, @arsenm wrote:

Missing test?

https://reviews.llvm.org/D108208 test covers this

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

if (DataDwordVT.isVector())
     Data = padEltsToUndef(DAG, DL, DataDwordVT, Data,
                           NumDataDwords - MaskPopDwords);
 
   if (IsD16)
     Data = adjustLoadValueTypeImpl(Data, ReqRetVT, DL, DAG, Unpacked);
 
   EVT LegalReqRetVT = ReqRetVT;
   if (!ReqRetVT.isVector()) {
+    if (!Data.getValueType().isInteger())
+      Data = DAG.getNode(ISD::BITCAST, DL,
+                         Data.getValueType().changeTypeToInteger(), Data);
     Data = DAG.getNode(ISD::TRUNCATE, DL, ReqRetVT.changeTypeToInteger(), Data);
   } else {
     // We need to widen the return vector to a legal type
     if ((ReqRetVT.getVectorNumElements() % 2) == 1 &&
         ReqRetVT.getVectorElementType().getSizeInBits() == 16) {
       LegalReqRetVT =
           EVT::getVectorVT(*DAG.getContext(), ReqRetVT.getVectorElementType(),
                            ReqRetVT.getVectorNumElements() + 1);