AMDGPU: Conversions always produce canonical results

Not sure why this was checking for denormals for f16.
My interpretation of the IEEE standard is conversions
should produce a canonical result, and the ISA manual
says denormals are created when appropriate.

llvm-svn: 339064
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 22d33f5..c598c6d 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -6775,16 +6775,11 @@
   case ISD::FSQRT:
   case ISD::FDIV:
   case ISD::FREM:
+  case ISD::FP_ROUND:
+  case ISD::FP_EXTEND:
   case AMDGPUISD::FMUL_LEGACY:
   case AMDGPUISD::FMAD_FTZ:
     return true;
-  case ISD::FP_ROUND:
-    return Op.getValueType().getScalarType() != MVT::f16 ||
-           Subtarget->hasFP16Denormals();
-
-  case ISD::FP_EXTEND:
-    return Op.getOperand(0).getValueType().getScalarType() != MVT::f16 ||
-           Subtarget->hasFP16Denormals();
 
   // It can/will be lowered or combined as a bit operation.
   // Need to check their input recursively to handle.