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8379667: C2: Deep recursion with cmovP_regNode::bottom_type #30765

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108 changes: 0 additions & 108 deletions src/hotspot/share/adlc/formssel.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -453,14 +453,6 @@ Form::DataType InstructForm::is_ideal_store() const {
return _matrule->is_ideal_store();
}

// Return 'true' if this instruction matches an ideal vector node
bool InstructForm::is_vector() const {
if( _matrule == nullptr ) return false;

return _matrule->is_vector();
}


// Return the input register that must match the output register
// If this is not required, return 0
uint InstructForm::two_address(FormDict &globals) {
Expand Down Expand Up @@ -767,51 +759,6 @@ int InstructForm::memory_operand(FormDict &globals) const {
return NO_MEMORY_OPERAND;
}

// This instruction captures the machine-independent bottom_type
// Expected use is for pointer vs oop determination for LoadP
bool InstructForm::captures_bottom_type(FormDict &globals) const {
if (_matrule && _matrule->_rChild &&
(!strcmp(_matrule->_rChild->_opType,"CastPP") || // new result type
!strcmp(_matrule->_rChild->_opType,"CastDD") ||
!strcmp(_matrule->_rChild->_opType,"CastFF") ||
!strcmp(_matrule->_rChild->_opType,"CastII") ||
!strcmp(_matrule->_rChild->_opType,"CastLL") ||
!strcmp(_matrule->_rChild->_opType,"CastVV") ||
!strcmp(_matrule->_rChild->_opType,"CastX2P") || // new result type
!strcmp(_matrule->_rChild->_opType,"DecodeN") ||
!strcmp(_matrule->_rChild->_opType,"EncodeP") ||
!strcmp(_matrule->_rChild->_opType,"DecodeNKlass") ||
!strcmp(_matrule->_rChild->_opType,"EncodePKlass") ||
!strcmp(_matrule->_rChild->_opType,"LoadN") ||
!strcmp(_matrule->_rChild->_opType,"LoadNKlass") ||
!strcmp(_matrule->_rChild->_opType,"CreateEx") || // type of exception
!strcmp(_matrule->_rChild->_opType,"CheckCastPP") ||
!strcmp(_matrule->_rChild->_opType,"GetAndSetP") ||
!strcmp(_matrule->_rChild->_opType,"GetAndSetN") ||
!strcmp(_matrule->_rChild->_opType,"RotateLeft") ||
!strcmp(_matrule->_rChild->_opType,"RotateRight") ||
#if INCLUDE_SHENANDOAHGC
!strcmp(_matrule->_rChild->_opType,"ShenandoahCompareAndExchangeP") ||
!strcmp(_matrule->_rChild->_opType,"ShenandoahCompareAndExchangeN") ||
#endif
!strcmp(_matrule->_rChild->_opType,"StrInflatedCopy") ||
!strcmp(_matrule->_rChild->_opType,"VectorCmpMasked")||
!strcmp(_matrule->_rChild->_opType,"VectorMaskGen")||
!strcmp(_matrule->_rChild->_opType,"VerifyVectorAlignment")||
!strcmp(_matrule->_rChild->_opType,"CompareAndExchangeP") ||
!strcmp(_matrule->_rChild->_opType,"CompareAndExchangeN"))) return true;
else if ( is_ideal_load() == Form::idealP ) return true;
else if ( is_ideal_store() != Form::none ) return true;

if (needs_base_oop_edge(globals)) return true;

if (is_vector()) return true;
if (is_mach_constant()) return true;

return false;
}


// Access instr_cost attribute or return null.
const char* InstructForm::cost() {
for (Attribute* cur = _attribs; cur != nullptr; cur = (Attribute*)cur->_next) {
Expand Down Expand Up @@ -1181,9 +1128,6 @@ const char *InstructForm::mach_base_class(FormDict &globals) const {
}
else if (is_mach_constant()) {
return "MachConstantNode";
}
else if (captures_bottom_type(globals)) {
return "MachTypeNode";
} else {
return "MachNode";
}
Expand Down Expand Up @@ -4337,58 +4281,6 @@ Form::DataType MatchRule::is_ideal_load() const {
return ideal_load;
}

bool MatchRule::is_vector() const {
static const char *vector_list[] = {
"AddVB","AddVS","AddVI","AddVL","AddVHF","AddVF","AddVD",
"SubVB","SubVS","SubVI","SubVL","SubVHF","SubVF","SubVD",
"MulVB","MulVS","MulVI","MulVL","MulVHF","MulVF","MulVD",
"DivVHF","DivVF","DivVD",
"AbsVB","AbsVS","AbsVI","AbsVL","AbsVF","AbsVD",
"NegVF","NegVD","NegVI","NegVL",
"SqrtVD","SqrtVF","SqrtVHF",
"AndV" ,"XorV" ,"OrV",
"MaxV", "MinV", "MinVHF", "MaxVHF", "UMinV", "UMaxV",
"CompressV", "ExpandV", "CompressM", "CompressBitsV", "ExpandBitsV",
"AddReductionVI", "AddReductionVL",
"AddReductionVHF", "AddReductionVF", "AddReductionVD",
"MulReductionVI", "MulReductionVL",
"MulReductionVHF", "MulReductionVF", "MulReductionVD",
"MaxReductionV", "MinReductionV",
"AndReductionV", "OrReductionV", "XorReductionV",
"MulAddVS2VI", "MacroLogicV",
"LShiftCntV","RShiftCntV",
"LShiftVB","LShiftVS","LShiftVI","LShiftVL",
"RShiftVB","RShiftVS","RShiftVI","RShiftVL",
"URShiftVB","URShiftVS","URShiftVI","URShiftVL",
"Replicate","ReverseV","ReverseBytesV",
"RoundDoubleModeV","RotateLeftV" , "RotateRightV", "LoadVector","StoreVector",
"LoadVectorGather", "StoreVectorScatter", "LoadVectorGatherMasked", "StoreVectorScatterMasked",
"SelectFromTwoVector", "VectorTest", "VectorLoadMask", "VectorStoreMask", "VectorBlend", "VectorInsert",
"VectorRearrange", "VectorLoadShuffle", "VectorLoadConst",
"VectorCastB2X", "VectorCastS2X", "VectorCastI2X",
"VectorCastL2X", "VectorCastF2X", "VectorCastD2X", "VectorCastF2HF", "VectorCastHF2F",
"VectorUCastB2X", "VectorUCastS2X", "VectorUCastI2X",
"VectorMaskWrapper","VectorMaskCmp","VectorReinterpret","LoadVectorMasked","StoreVectorMasked",
"FmaVD", "FmaVF", "FmaVHF", "PopCountVI", "PopCountVL", "PopulateIndex", "VectorLongToMask",
"CountLeadingZerosV", "CountTrailingZerosV", "SignumVF", "SignumVD", "SaturatingAddV", "SaturatingSubV",
// Next are vector mask ops.
"MaskAll", "AndVMask", "OrVMask", "XorVMask", "VectorMaskCast",
"RoundVF", "RoundVD",
// Next are not supported currently.
"PackB","PackS","PackI","PackL","PackF","PackD","Pack2L","Pack2D",
"ExtractB","ExtractUB","ExtractC","ExtractS","ExtractI","ExtractL","ExtractF","ExtractD"
};
int cnt = sizeof(vector_list)/sizeof(char*);
if (_rChild) {
const char *opType = _rChild->_opType;
for (int i=0; i<cnt; i++)
if (strcmp(opType,vector_list[i]) == 0)
return true;
}
return false;
}


bool MatchRule::skip_antidep_check() const {
// Some loads operate on what is effectively immutable memory so we
// should skip the anti dep computations. For some of these nodes
Expand Down
9 changes: 1 addition & 8 deletions src/hotspot/share/adlc/formssel.hpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -169,7 +169,6 @@ class InstructForm : public Form {
virtual bool is_ideal_safepoint() const; // node matches 'SafePoint'
virtual bool is_ideal_nop() const; // node matches 'Nop'
virtual bool is_ideal_control() const; // control node
virtual bool is_vector() const; // vector instruction

virtual Form::CallType is_ideal_call() const; // matches ideal 'Call'
virtual Form::DataType is_ideal_load() const; // node matches ideal 'LoadXNode'
Expand Down Expand Up @@ -199,11 +198,6 @@ class InstructForm : public Form {
MANY_MEMORY_OPERANDS = 999999
};


// This instruction captures the machine-independent bottom_type
// Expected use is for pointer vs oop determination for LoadP
virtual bool captures_bottom_type(FormDict& globals) const;

virtual const char *cost(); // Access ins_cost attribute
virtual uint num_opnds(); // Count of num_opnds for MachNode class
// Counts USE_DEF opnds twice. See also num_unique_opnds().
Expand Down Expand Up @@ -1065,7 +1059,6 @@ class MatchRule : public MatchNode {
bool is_ideal_goto() const; // node matches ideal 'Goto'
bool is_ideal_loopEnd() const; // node matches ideal 'LoopEnd'
bool is_ideal_bool() const; // node matches ideal 'Bool'
bool is_vector() const; // vector instruction
Form::DataType is_ideal_load() const;// node matches ideal 'LoadXNode'
// Should antidep checks be disabled for this rule
// See definition of MatchRule::skip_antidep_check
Expand Down
41 changes: 17 additions & 24 deletions src/hotspot/share/adlc/output_c.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1324,11 +1324,8 @@ static void generate_peepreplace( FILE *fp, FormDict &globals, int peephole_numb
fprintf(fp, " root->add_req(inst%d->in(%d)); // unmatched ideal edge\n",
inst_num, unmatched_edge);
}
// If new instruction captures bottom type
if( root_form->captures_bottom_type(globals) ) {
// Get bottom type from instruction whose result we are replacing
fprintf(fp, " root->_bottom_type = inst%d->bottom_type();\n", inst_num);
}
// Get bottom type from instruction whose result we are replacing
fprintf(fp, " root->_bottom_type = inst%d->bottom_type();\n", inst_num);
// Define result register and result operand
fprintf(fp, " ra_->set_oop (root, ra_->is_oop(inst%d));\n", inst_num);
fprintf(fp, " ra_->set_pair(root->_idx, ra_->get_reg_second(inst%d), ra_->get_reg_first(inst%d));\n", inst_num, inst_num);
Expand Down Expand Up @@ -1587,11 +1584,8 @@ void ArchDesc::defineExpand(FILE *fp, InstructForm *node) {
fprintf(fp, " ((MachIfNode*)n%d)->_fcnt = _fcnt;\n", cnt);
}

// Fill in the bottom_type where requested
if (node->captures_bottom_type(_globalNames) &&
new_inst->captures_bottom_type(_globalNames)) {
fprintf(fp, " ((MachTypeNode*)n%d)->_bottom_type = bottom_type();\n", cnt);
}
// Fill in the bottom_type
fprintf(fp, " n%d->_bottom_type = bottom_type();\n", cnt);

const char *resultOper = new_inst->reduce_result();
fprintf(fp," n%d->set_opnd_array(0, state->MachOperGenerator(%s));\n",
Expand Down Expand Up @@ -3965,13 +3959,15 @@ void ArchDesc::buildMachNode(FILE *fp_cpp, InstructForm *inst, const char *inden
}
}

// Fill in the bottom_type where requested
if (inst->captures_bottom_type(_globalNames)) {
if (strncmp("MachCall", inst->mach_base_class(_globalNames), strlen("MachCall")) != 0
&& strncmp("MachIf", inst->mach_base_class(_globalNames), strlen("MachIf")) != 0) {
fprintf(fp_cpp, "%s node->_bottom_type = _leaf->bottom_type();\n", indent);
}
// Fill in the bottom_type
if (inst->_matrule != nullptr && strcmp(inst->_matrule->_opType, "PrefetchAllocation") == 0) {
// Special case, with AllocatePrefetchStyle == 3, this should be Type::MEMORY, but the graph
// seems unsound, needs further investigation
Comment on lines +3964 to +3965
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@anton-seoane anton-seoane Apr 20, 2026

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What do you mean by "unsound" here? Can you create a follow-up to track this?

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@merykitty merykitty Apr 20, 2026

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Currently, in the ideal graph, a PrefetchAllocationNode is a Type::ABIO or Type::MEMORY. As a result, they are connected to previous and subsequent abio and memory nodes, respectively. However, when lowered to MachNodes, since the rule are declared match(PrefetchAllocation mem), they become Type::BOTTOM, but their inputs and outputs are still abio or memory nodes, hence the unsoundness.

With the PR, at least when AllocatePrefetchStyle != 3, they preserve their correct type after matching. For AllocatePrefetchStyle == 3, it is more difficult, because memory nodes participate in anti-dependency computations, so we need to make further modifications to ensure that a PrefetchAllocationNode has a control input, and they act as a full store (its anti-dependencies do not need computing).

I filed JDK-8382547.

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@anton-seoane anton-seoane Apr 21, 2026

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I see, thanks!

fprintf(fp_cpp, "%s node->_bottom_type = Type::ABIO;\n", indent);
} else {
fprintf(fp_cpp, "%s node->_bottom_type = _leaf->bottom_type();\n", indent);
}

if( inst->is_ideal_if() ) {
fprintf(fp_cpp, "%s node->_prob = _leaf->as_If()->_prob;\n", indent);
fprintf(fp_cpp, "%s node->_fcnt = _leaf->as_If()->_fcnt;\n", indent);
Expand Down Expand Up @@ -4026,10 +4022,8 @@ void InstructForm::define_cisc_version(ArchDesc& AD, FILE* fp_cpp) {
fprintf(fp_cpp, "MachNode *%sNode::cisc_version(int offset) {\n", this->_ident);
// Create the MachNode object
fprintf(fp_cpp, " %sNode *node = new %sNode();\n", name, name);
// Fill in the bottom_type where requested
if ( this->captures_bottom_type(AD.globalNames()) ) {
fprintf(fp_cpp, " node->_bottom_type = bottom_type();\n");
}
// Fill in the bottom_type
fprintf(fp_cpp, " node->_bottom_type = bottom_type();\n");

uint cur_num_opnds = num_opnds();
if (cur_num_opnds > 1 && cur_num_opnds != num_unique_opnds()) {
Expand Down Expand Up @@ -4075,10 +4069,9 @@ void InstructForm::define_short_branch_methods(ArchDesc& AD, FILE* fp_cpp) {
fprintf(fp_cpp, " node->_prob = _prob;\n");
fprintf(fp_cpp, " node->_fcnt = _fcnt;\n");
}
// Fill in the bottom_type where requested
if ( this->captures_bottom_type(AD.globalNames()) ) {
fprintf(fp_cpp, " node->_bottom_type = bottom_type();\n");
}

// Fill in the bottom_type
fprintf(fp_cpp, " node->_bottom_type = bottom_type();\n");

fprintf(fp_cpp, "\n");
// Short branch version must use same node index for access
Expand Down
108 changes: 1 addition & 107 deletions src/hotspot/share/adlc/output_h.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -1841,112 +1841,6 @@ void ArchDesc::declareClasses(FILE *fp) {
fprintf(fp," virtual const Pipeline *pipeline() const;\n");
}

// Generate virtual function for MachNodeX::bottom_type when necessary
//
// Note on accuracy: Pointer-types of machine nodes need to be accurate,
// or else alias analysis on the matched graph may produce bad code.
// Moreover, the aliasing decisions made on machine-node graph must be
// no less accurate than those made on the ideal graph, or else the graph
// may fail to schedule. (Reason: Memory ops which are reordered in
// the ideal graph might look interdependent in the machine graph,
// thereby removing degrees of scheduling freedom that the optimizer
// assumed would be available.)
//
// %%% We should handle many of these cases with an explicit ADL clause:
// instruct foo() %{ ... bottom_type(TypeRawPtr::BOTTOM); ... %}
if( data_type != Form::none ) {
// A constant's bottom_type returns a Type containing its constant value

// !!!!!
// Convert all ints, floats, ... to machine-independent TypeXs
// as is done for pointers
//
// Construct appropriate constant type containing the constant value.
fprintf(fp," virtual const class Type *bottom_type() const {\n");
switch( data_type ) {
case Form::idealI:
fprintf(fp," return TypeInt::make(opnd_array(1)->constant());\n");
break;
case Form::idealP:
case Form::idealN:
case Form::idealNKlass:
fprintf(fp," return opnd_array(1)->type();\n");
break;
case Form::idealD:
fprintf(fp," return TypeD::make(opnd_array(1)->constantD());\n");
break;
case Form::idealH:
fprintf(fp," return TypeH::make(opnd_array(1)->constantH());\n");
break;
case Form::idealF:
fprintf(fp," return TypeF::make(opnd_array(1)->constantF());\n");
break;
case Form::idealL:
fprintf(fp," return TypeLong::make(opnd_array(1)->constantL());\n");
break;
default:
assert( false, "Unimplemented()" );
break;
}
fprintf(fp," };\n");
}
/* else if ( instr->_matrule && instr->_matrule->_rChild &&
( strcmp("ConvF2I",instr->_matrule->_rChild->_opType)==0
|| strcmp("ConvD2I",instr->_matrule->_rChild->_opType)==0 ) ) {
// !!!!! !!!!!
// Provide explicit bottom type for conversions to int
// On Intel the result operand is a stackSlot, untyped.
fprintf(fp," virtual const class Type *bottom_type() const {");
fprintf(fp, " return TypeInt::INT;");
fprintf(fp, " };\n");
}*/
else if( instr->is_ideal_copy() &&
!strcmp(instr->_matrule->_lChild->_opType,"stackSlotP") ) {
// !!!!!
// Special hack for ideal Copy of pointer. Bottom type is oop or not depending on input.
fprintf(fp," const Type *bottom_type() const { return in(1)->bottom_type(); } // Copy?\n");
}
else if( instr->is_ideal_loadPC() ) {
// LoadPCNode provides the return address of a call to native code.
// Define its bottom type to be TypeRawPtr::BOTTOM instead of TypePtr::BOTTOM
// since it is a pointer to an internal VM location and must have a zero offset.
// Allocation detects derived pointers, in part, by their non-zero offsets.
fprintf(fp," const Type *bottom_type() const { return TypeRawPtr::BOTTOM; } // LoadPC?\n");
}
else if( instr->is_ideal_box() ) {
// BoxNode provides the address of a stack slot.
// Define its bottom type to be TypeRawPtr::BOTTOM instead of TypePtr::BOTTOM
// This prevents raise_above_anti_dependences from complaining. It will
// complain if it sees that the pointer base is TypePtr::BOTTOM since
// it doesn't understand what that might alias.
fprintf(fp," const Type *bottom_type() const { return TypeRawPtr::BOTTOM; } // Box?\n");
}
else if (instr->_matrule && instr->_matrule->_rChild &&
(!strcmp(instr->_matrule->_rChild->_opType,"CMoveP") || !strcmp(instr->_matrule->_rChild->_opType,"CMoveN")) ) {
int offset = 1;
// Special special hack to see if the Cmp? has been incorporated in the conditional move
MatchNode *rl = instr->_matrule->_rChild->_lChild;
if (rl && !strcmp(rl->_opType, "Binary") && rl->_rChild && strncmp(rl->_rChild->_opType, "Cmp", 3) == 0) {
offset = 2;
fprintf(fp," const Type *bottom_type() const { if (req() == 3) return in(2)->bottom_type();\n\tconst Type *t = in(oper_input_base()+%d)->bottom_type(); return (req() <= oper_input_base()+%d) ? t : t->meet(in(oper_input_base()+%d)->bottom_type()); } // %s\n",
offset, offset+1, offset+1, instr->_matrule->_rChild->_opType);
} else {
// Special hack for ideal CMove; ideal type depends on inputs
fprintf(fp," const Type *bottom_type() const { const Type *t = in(oper_input_base()+%d)->bottom_type(); return (req() <= oper_input_base()+%d) ? t : t->meet(in(oper_input_base()+%d)->bottom_type()); } // %s\n",
offset, offset+1, offset+1, instr->_matrule->_rChild->_opType);
}
}
else if (instr->is_tls_instruction()) {
// Special hack for tlsLoadP
fprintf(fp," const Type *bottom_type() const { return TypeRawPtr::BOTTOM; } // tlsLoadP\n");
}
else if ( instr->is_ideal_if() ) {
fprintf(fp," const Type *bottom_type() const { return TypeTuple::IFBOTH; } // matched IfNode\n");
}
else if ( instr->is_ideal_membar() ) {
fprintf(fp," const Type *bottom_type() const { return TypeTuple::MEMBAR; } // matched MemBar\n");
}

// Check where 'ideal_type' must be customized
/*
if ( instr->_matrule && instr->_matrule->_rChild &&
Expand Down
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