From a894266d285fb6c4dfe259942d6c336c1afdc546 Mon Sep 17 00:00:00 2001
From: Hal Finkel <hfinkel@anl.gov>
Date: Mon, 31 Aug 2015 18:38:55 +0000
Subject: [PATCH] [DAGCombine] Remove some old dead code for forming SETCC
 nodes

This code was dead when it was committed in r23665 (Oct 7, 2005), and before it
reaches its 10th anniversary, it really should go. We can always bring it back
if we'd like, but it forms more SETCC nodes, and the way we do legality
checking on SETCC nodes is wrong in a number of places, and removing this means
fewer places to fix. NFC.

llvm-svn: 246466
---
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 45 -------------------
 1 file changed, 45 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 250c4282e6ff..1cb128328841 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -13762,51 +13762,6 @@ SDValue DAGCombiner::SimplifySelectCC(SDLoc DL, SDValue N0, SDValue N1,
     }
   }
 
-  // Check to see if this is the equivalent of setcc
-  // FIXME: Turn all of these into setcc if setcc if setcc is legal
-  // otherwise, go ahead with the folds.
-  if (0 && isNullConstant(N3) && isOneConstant(N2)) {
-    EVT XType = N0.getValueType();
-    if (!LegalOperations ||
-        TLI.isOperationLegal(ISD::SETCC, getSetCCResultType(XType))) {
-      SDValue Res = DAG.getSetCC(DL, getSetCCResultType(XType), N0, N1, CC);
-      if (Res.getValueType() != VT)
-        Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res);
-      return Res;
-    }
-
-    // fold (seteq X, 0) -> (srl (ctlz X, log2(size(X))))
-    if (isNullConstant(N1) && CC == ISD::SETEQ &&
-        (!LegalOperations ||
-         TLI.isOperationLegal(ISD::CTLZ, XType))) {
-      SDValue Ctlz = DAG.getNode(ISD::CTLZ, SDLoc(N0), XType, N0);
-      return DAG.getNode(ISD::SRL, DL, XType, Ctlz,
-                         DAG.getConstant(Log2_32(XType.getSizeInBits()),
-                                         SDLoc(Ctlz),
-                                       getShiftAmountTy(Ctlz.getValueType())));
-    }
-    // fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1))
-    if (isNullConstant(N1) && CC == ISD::SETGT) {
-      SDLoc DL(N0);
-      SDValue NegN0 = DAG.getNode(ISD::SUB, DL,
-                                  XType, DAG.getConstant(0, DL, XType), N0);
-      SDValue NotN0 = DAG.getNOT(DL, N0, XType);
-      return DAG.getNode(ISD::SRL, DL, XType,
-                         DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0),
-                         DAG.getConstant(XType.getSizeInBits() - 1, DL,
-                                         getShiftAmountTy(XType)));
-    }
-    // fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1))
-    if (isAllOnesConstant(N1) && CC == ISD::SETGT) {
-      SDLoc DL(N0);
-      SDValue Sign = DAG.getNode(ISD::SRL, DL, XType, N0,
-                                 DAG.getConstant(XType.getSizeInBits() - 1, DL,
-                                         getShiftAmountTy(N0.getValueType())));
-      return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, DL,
-                                                                    XType));
-    }
-  }
-
   // Check to see if this is an integer abs.
   // select_cc setg[te] X,  0,  X, -X ->
   // select_cc setgt    X, -1,  X, -X ->