Add TODOs to handle ppcf128 for one of the halves.

Author: amy-kwan

llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp

@@ -1969,6 +1969,7 @@ void DAGTypeLegalizer::ExpandFloatRes_FNEG(SDNode *N, SDValue &Lo,
 
 void DAGTypeLegalizer::ExpandFloatRes_AssertNoFPClass(SDNode *N, SDValue &Lo,
                                                       SDValue &Hi) {
+  // TODO: Handle ppcf128 by preserving AssertNoFPClass for one of the halves.
   SDLoc dl(N);
   GetExpandedFloat(N->getOperand(0), Lo, Hi);
 }

llvm/test/CodeGen/PowerPC/nofpclass.ll

@@ -2,6 +2,10 @@
 ; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s
 ; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff < %s | FileCheck %s
 
+; TODO: Update this test after adding the proper expansion of nofpclass for
+; ppc_fp128 to test with more masks and to demonstrate preserving nofpclass
+; after legalization.
+
 define ppc_fp128 @f(ppc_fp128 nofpclass(nan) %s) {
 ; CHECK-LABEL: f:
 ; CHECK:       # %bb.0: # %entry