public AddPhiIncoming ( |
||
phiNode | ||
value | ||
block | ||
Результат | void |
public override Value CodeGen(IRBuilder builder) { Value startV = this.Start.CodeGen(builder); if(startV.IsNull) return startV; BasicBlock startBlock = builder.GetInsertPoint(); Function func = startBlock.GetParent(); BasicBlock loopBB = func.AppendBasicBlock("loop"); builder.BuildBr(loopBB); builder.SetInsertPoint(loopBB); Value variable = builder.BuildPhi(TypeRef.CreateDouble(), this.VarName, new PhiIncoming(startV, startBlock)); /* Within the loop, the variable is defined equal to the PHI node. If it * shadows an existing variable, we have to restore it, so save it * now. */ Value oldVal = Value.Null; CodeGenManager.NamedValues.TryGetValue(this.VarName, out oldVal); CodeGenManager.NamedValues[this.VarName] = variable; /* Emit the body of the loop. This, like any other expr, can change the * current BB. Note that we ignore the value computed by the body, but * don't allow an error */ Body.CodeGen(builder); // Emit the step value; Value stepV = Value.Null; if(this.Step != null) stepV = this.Step.CodeGen(builder); else stepV = Value.CreateConstDouble(1); Value nextVar = builder.BuildFAdd(variable, stepV, "nextvar"); // Compute the end condition Value endCond = this.End.CodeGen(builder); endCond = builder.BuildFCmp(endCond, LLVMRealPredicate.RealONE, Value.CreateConstDouble(0), "loopcond"); BasicBlock loopEndBB = builder.GetInsertPoint(); BasicBlock afterBB = func.AppendBasicBlock("afterloop"); builder.BuildCondBr(endCond, loopBB, afterBB); builder.SetInsertPoint(afterBB); builder.AddPhiIncoming(variable, nextVar, loopEndBB); if(!oldVal.IsNull) CodeGenManager.NamedValues[this.VarName] = oldVal; return Value.CreateConstDouble(0); }