address comments

Author: AlexMaclean

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -18753,7 +18753,9 @@ SDValue DAGCombiner::rebuildSetCC(SDValue N) {
       EVT SetCCVT = N.getValueType();
       if (LegalTypes)
         SetCCVT = getSetCCResultType(SetCCVT);
-      // Replace the uses of XOR with SETCC
+      // Replace the uses of XOR with SETCC. Note, avoid this transformation if
+      // it would introduce illegal operations post-legalization as this can
+      // result in an infinite loop.
       const ISD::CondCode CC = Equal ? ISD::SETEQ : ISD::SETNE;
       if (!LegalOperations || TLI.isCondCodeLegal(CC, Op0.getSimpleValueType()))
         return DAG.getSetCC(SDLoc(N), SetCCVT, Op0, Op1, CC);

llvm/lib/Target/NVPTX/NVPTXInstrInfo.td

@@ -2120,17 +2120,6 @@ defm : ISET_FORMAT_UNSIGNED<setule, CmpLE>;
 defm : ISET_FORMAT_UNSIGNED<setueq, CmpEQ>;
 defm : ISET_FORMAT_UNSIGNED<setune, CmpNE>;
 
-// i1 compares
-def : Pat<(setne Int1Regs:$a, Int1Regs:$b),
-          (XORb1rr Int1Regs:$a, Int1Regs:$b)>;
-def : Pat<(setune Int1Regs:$a, Int1Regs:$b),
-          (XORb1rr Int1Regs:$a, Int1Regs:$b)>;
-
-def : Pat<(seteq Int1Regs:$a, Int1Regs:$b),
-          (NOT1 (XORb1rr Int1Regs:$a, Int1Regs:$b))>;
-def : Pat<(setueq Int1Regs:$a, Int1Regs:$b),
-          (NOT1 (XORb1rr Int1Regs:$a, Int1Regs:$b))>;
-
 // comparisons of i8 extracted with BFE as i32
 // It's faster to do comparison directly on i32 extracted by BFE,
 // instead of the long conversion and sign extending.