Remove the last bit of constant folding from LinearizeExprTree (most …

…of it was

removed in commit 168035, but I missed this bit).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168292 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/Reassociate.cpp

@@ -423,10 +423,6 @@ static bool LinearizeExprTree(BinaryOperator *I,
   assert(Instruction::isAssociative(Opcode) &&
          Instruction::isCommutative(Opcode) &&
          "Expected an associative and commutative operation!");
-  // If we see an absorbing element then the entire expression must be equal to
-  // it.  For example, if this is a multiplication expression and zero occurs as
-  // an operand somewhere in it then the result of the expression must be zero.
-  Constant *Absorber = ConstantExpr::getBinOpAbsorber(Opcode, I->getType());
 
   // Visit all operands of the expression, keeping track of their weight (the
   // number of paths from the expression root to the operand, or if you like
@@ -474,13 +470,6 @@ static bool LinearizeExprTree(BinaryOperator *I,
       DEBUG(dbgs() << "OPERAND: " << *Op << " (" << Weight << ")\n");
       assert(!Op->use_empty() && "No uses, so how did we get to it?!");
 
-      // If the expression contains an absorbing element then there is no need
-      // to analyze it further: it must evaluate to the absorbing element.
-      if (Op == Absorber && !Weight.isMinValue()) {
-        Ops.push_back(std::make_pair(Absorber, APInt(Bitwidth, 1)));
-        return MadeChange;
-      }
-
       // If this is a binary operation of the right kind with only one use then
       // add its operands to the expression.
       if (BinaryOperator *BO = isReassociableOp(Op, Opcode)) {