jdk
1/*
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24
25#include "precompiled.hpp"26#include "memory/allocation.inline.hpp"27#include "opto/callnode.hpp"28#include "opto/cfgnode.hpp"29#include "opto/phaseX.hpp"30#include "opto/regmask.hpp"31#include "opto/rootnode.hpp"32#include "opto/subnode.hpp"33#include "opto/type.hpp"34
35//------------------------------Ideal------------------------------------------
36// Remove dead inputs
37Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {38bool modified = false;39for( uint i = 1; i < req(); i++ ) { // For all inputs40// Check for and remove dead inputs41if( phase->type(in(i)) == Type::TOP ) {42del_req(i--); // Delete TOP inputs43modified = true;44}45}46
47// I used to do tail-splitting in the Ideal graph here, but it does not48// work. The tail-splitting forces values live into the Return to be49// ready at a point which dominates the split returns. This forces Stores50// to be hoisted high. The "proper" fix would be to split Stores down51// each path, but this makes the split unprofitable. If we want to do this52// optimization, it needs to be done after allocation so we can count all53// the instructions needing to be cloned in the cost metric.54
55// There used to be a spoof here for caffeine marks which completely56// eliminated very simple self-recursion recursions, but it's not worth it.57// Deep inlining of self-calls gets nearly all of the same benefits.58// If we want to get the rest of the win later, we should pattern match59// simple recursive call trees to closed-form solutions.60
61return modified ? this : nullptr;62}
63
64//=============================================================================
65HaltNode::HaltNode(Node* ctrl, Node* frameptr, const char* halt_reason, bool reachable)66: Node(TypeFunc::Parms), _halt_reason(halt_reason), _reachable(reachable) {67init_class_id(Class_Halt);68Node* top = Compile::current()->top();69init_req(TypeFunc::Control, ctrl );70init_req(TypeFunc::I_O, top);71init_req(TypeFunc::Memory, top);72init_req(TypeFunc::FramePtr, frameptr );73init_req(TypeFunc::ReturnAdr,top);74}
75
76const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }77uint HaltNode::size_of() const { return sizeof(*this); }78
79//------------------------------Ideal------------------------------------------
80Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {81return remove_dead_region(phase, can_reshape) ? this : nullptr;82}
83
84//------------------------------Value------------------------------------------
85const Type* HaltNode::Value(PhaseGVN* phase) const {86return ( phase->type(in(TypeFunc::Control)) == Type::TOP)87? Type::TOP88: Type::BOTTOM;89}
90
91const RegMask &HaltNode::out_RegMask() const {92return RegMask::Empty;93}
94