Commit e299a428 authored by Nikita Popov's avatar Nikita Popov
Browse files

[ConstantFold] Remove redundant bitcast icmp handling (NFCI) 

This code excludes vector/scalar and FP bitcasts. All other
integer/pointer bitcasts are no-op bitcasts and will be removed
entirely.
parent 9915ebaa

llvm/lib/IR/ConstantFold.cpp

+0 −14
Original line number Diff line number Diff line
@@ -1451,20 +1451,6 @@ Constant *llvm::ConstantFoldCompareInstruction(CmpInst::Predicate Predicate, 
    if (Result != -1)

      return ConstantInt::get(ResultTy, Result);



    // If the right hand side is a bitcast, try using its inverse to simplify

    // it by moving it to the left hand side.  We can't do this if it would turn

    // a vector compare into a scalar compare or visa versa, or if it would turn

    // the operands into FP values.

    if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {

      Constant *CE2Op0 = CE2->getOperand(0);

      if (CE2->getOpcode() == Instruction::BitCast &&

          CE2->getType()->isVectorTy() == CE2Op0->getType()->isVectorTy() &&

          !CE2Op0->getType()->isFPOrFPVectorTy()) {

        Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());

        return ConstantExpr::getICmp(Predicate, Inverse, CE2Op0);

      }

    }



    if ((!isa<ConstantExpr>(C1) && isa<ConstantExpr>(C2)) ||

        (C1->isNullValue() && !C2->isNullValue())) {

      // If C2 is a constant expr and C1 isn't, flip them around and fold the