[clang] [llvm] [RFC][WIP][AMDGPU] Use `bf16` instead of `i16` for bfloat (PR #80908)

[Shilei Tian via cfe-commits]

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@@ -1562,8 +1562,9 @@ bool IRTranslator::translateBitCast(const User &U,
 
 bool IRTranslator::translateCast(unsigned Opcode, const User &U,
                                  MachineIRBuilder &MIRBuilder) {
-  if (U.getType()->getScalarType()->isBFloatTy() ||
-      U.getOperand(0)->getType()->getScalarType()->isBFloatTy())
+  if (Opcode != TargetOpcode::G_BITCAST &&
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shiltian wrote:

I think bitcast can still be supported even if we don't know how to convert from bfloat to other types mentioned in #71470. If so, we might want a separate patch for this.

https://github.com/llvm/llvm-project/pull/80908