[DAGCombine] Revert of recommit of "binop-with-const hoisting" patches

I was looking into an endless combine loop the uncommitted follow-up patch
was causing, and it appears even these patches can exibit such an
endless loop. The root cause is that we try to hoist one binop (add/sub) with
constant operand, and if we get two such binops both of which are
eligible for this hoisting, we get stuck.

Some cases may highlight missing constant-folds.

Reverts r361871,r361872,r361873,r361874.

llvm-svn: 362109

1 files changed, 0 insertions, 34 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 1518efd1256..d2045d764a0 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2303,13 +2303,6 @@ SDValue DAGCombiner::visitADDLike(SDNode *N) {
     }
   }
 
-  // (x - y) + -1  ->  add (xor y, -1), x
-  if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB &&
-      isAllOnesOrAllOnesSplat(N1)) {
-    SDValue Xor = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1), N1);
-    return DAG.getNode(ISD::ADD, DL, VT, Xor, N0.getOperand(0));
-  }
-
   if (SDValue Combined = visitADDLikeCommutative(N0, N1, N))
     return Combined;
 
@@ -2930,33 +2923,6 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
   if (SDValue V = foldAddSubMasked1(false, N0, N1, DAG, SDLoc(N)))
     return V;
 
-  // (x - y) - 1  ->  add (xor y, -1), x
-  if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && isOneOrOneSplat(N1)) {
-    SDValue Xor = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1),
-                              DAG.getAllOnesConstant(DL, VT));
-    return DAG.getNode(ISD::ADD, DL, VT, Xor, N0.getOperand(0));
-  }
-
-  // Hoist one-use addition by constant:  (x + C) - y  ->  (x - y) + C
-  if (N0.hasOneUse() && N0.getOpcode() == ISD::ADD &&
-      isConstantOrConstantVector(N0.getOperand(1))) {
-    SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), N1);
-    return DAG.getNode(ISD::ADD, DL, VT, Sub, N0.getOperand(1));
-  }
-  // y - (x + C)  ->  (y - x) - C
-  if (N1.hasOneUse() && N1.getOpcode() == ISD::ADD &&
-      isConstantOrConstantVector(N1.getOperand(1))) {
-    SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0, N1.getOperand(0));
-    return DAG.getNode(ISD::SUB, DL, VT, Sub, N1.getOperand(1));
-  }
-  // (x - C) - y  ->  (x - y) - C
-  // This is necessary because SUB(X,C) -> ADD(X,-C) doesn't work for vectors.
-  if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB &&
-      isConstantOrConstantVector(N0.getOperand(1))) {
-    SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), N1);
-    return DAG.getNode(ISD::SUB, DL, VT, Sub, N0.getOperand(1));
-  }
-
   // If the target's bool is represented as 0/-1, prefer to make this 'add 0/-1'
   // rather than 'sub 0/1' (the sext should get folded).
   // sub X, (zext i1 Y) --> add X, (sext i1 Y)