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[IR] BlockAddress doesn't use BasicBlock (#200772)
BlockAddress is the only non-terminator user of a BasicBlock, and it occurs very rarely. To speed up predecessor iteration, change BlockAddress to no longer use its BasicBlock. This should also make uselistorder_bb obsolete.
1 parent 1433381 commit 080286d

23 files changed

Lines changed: 24 additions & 202 deletions

‎llvm/docs/LangRef.rst‎

Lines changed: 0 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -4325,16 +4325,11 @@ Use-list directives may appear at function scope or global scope. They are not
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instructions, and have no effect on the semantics of the IR. When they're at
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function scope, they must appear after the terminator of the final basic block.
43274327

4328-
If basic blocks have their address taken via ``blockaddress()`` expressions,
4329-
``uselistorder_bb`` can be used to reorder their use-lists from outside their
4330-
function's scope.
4331-
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:Syntax:
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::
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43364332
uselistorder <ty> <value>, { <order-indexes> }
4337-
uselistorder_bb @function, %block { <order-indexes> }
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43394334
:Examples:
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@@ -4355,7 +4350,6 @@ function's scope.
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uselistorder ptr @global, { 1, 2, 0 }
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uselistorder i32 7, { 1, 0 }
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uselistorder i32 (i32) @bar, { 1, 0 }
4358-
uselistorder_bb @foo, %bb, { 5, 1, 3, 2, 0, 4 }
43594353

43604354
.. _source_filename:
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‎llvm/include/llvm/AsmParser/LLParser.h‎

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Original file line numberDiff line numberDiff line change
@@ -706,7 +706,6 @@ namespace llvm {
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707707
// Use-list order directives.
708708
bool parseUseListOrder(PerFunctionState *PFS = nullptr);
709-
bool parseUseListOrderBB();
710709
bool parseUseListOrderIndexes(SmallVectorImpl<unsigned> &Indexes);
711710
bool sortUseListOrder(Value *V, ArrayRef<unsigned> Indexes, SMLoc Loc);
712711
};

‎llvm/include/llvm/AsmParser/LLToken.h‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -388,7 +388,6 @@ enum Kind {
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389389
// Use-list order directives.
390390
kw_uselistorder,
391-
kw_uselistorder_bb,
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393392
// Summary index keywords
394393
kw_path,

‎llvm/include/llvm/IR/CFG.h‎

Lines changed: 5 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -51,37 +51,25 @@ class PredIterator {
5151
using Self = PredIterator<Ptr, USE_iterator>;
5252
USE_iterator It;
5353

54-
inline void advancePastNonTerminators() {
55-
// Loop to ignore non-terminator uses (for example BlockAddresses).
56-
while (!It.atEnd()) {
57-
if (auto *Inst = dyn_cast<Instruction>(*It)) {
58-
assert(Inst->isTerminator() && "BasicBlock used in non-terminator");
59-
break;
60-
}
61-
62-
++It;
63-
}
64-
}
65-
6654
public:
6755
PredIterator() = default;
68-
explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {
69-
advancePastNonTerminators();
70-
}
56+
explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {}
7157
inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {}
7258

7359
inline bool operator==(const Self& x) const { return It == x.It; }
7460
inline bool operator!=(const Self& x) const { return !operator==(x); }
7561

7662
inline reference operator*() const {
7763
assert(!It.atEnd() && "pred_iterator out of range!");
78-
return cast<Instruction>(*It)->getParent();
64+
auto *I = cast<Instruction>(*It);
65+
assert(I->isTerminator() && "BasicBlock used in non-terminator");
66+
return I->getParent();
7967
}
8068
inline pointer *operator->() const { return &operator*(); }
8169

8270
inline Self& operator++() { // Preincrement
8371
assert(!It.atEnd() && "pred_iterator out of range!");
84-
++It; advancePastNonTerminators();
72+
++It;
8573
return *this;
8674
}
8775

‎llvm/include/llvm/IR/Constants.h‎

Lines changed: 5 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1082,7 +1082,9 @@ class ConstantTargetNone final : public ConstantData {
10821082
class BlockAddress final : public Constant {
10831083
friend class Constant;
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1085-
constexpr static IntrusiveOperandsAllocMarker AllocMarker{1};
1085+
constexpr static IntrusiveOperandsAllocMarker AllocMarker{0};
1086+
1087+
BasicBlock *Block;
10861088

10871089
BlockAddress(Type *Ty, BasicBlock *BB);
10881090

@@ -1114,7 +1116,7 @@ class BlockAddress final : public Constant {
11141116
/// Transparently provide more efficient getOperand methods.
11151117
DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
11161118

1117-
BasicBlock *getBasicBlock() const { return cast<BasicBlock>(Op<0>().get()); }
1119+
BasicBlock *getBasicBlock() const { return Block; }
11181120
Function *getFunction() const { return getBasicBlock()->getParent(); }
11191121

11201122
/// Methods for support type inquiry through isa, cast, and dyn_cast:
@@ -1125,7 +1127,7 @@ class BlockAddress final : public Constant {
11251127

11261128
template <>
11271129
struct OperandTraits<BlockAddress>
1128-
: public FixedNumOperandTraits<BlockAddress, 1> {};
1130+
: public FixedNumOperandTraits<BlockAddress, 0> {};
11291131

11301132
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BlockAddress, Value)
11311133

‎llvm/lib/AsmParser/LLLexer.cpp‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -801,7 +801,6 @@ lltok::Kind LLLexer::LexIdentifier() {
801801

802802
// Use-list order directives.
803803
KEYWORD(uselistorder);
804-
KEYWORD(uselistorder_bb);
805804

806805
KEYWORD(personality);
807806
KEYWORD(cleanup);

‎llvm/lib/AsmParser/LLParser.cpp‎

Lines changed: 0 additions & 51 deletions
Original file line numberDiff line numberDiff line change
@@ -634,10 +634,6 @@ bool LLParser::parseTopLevelEntities() {
634634
if (parseUseListOrder())
635635
return true;
636636
break;
637-
case lltok::kw_uselistorder_bb:
638-
if (parseUseListOrderBB())
639-
return true;
640-
break;
641637
}
642638
}
643639
}
@@ -9472,53 +9468,6 @@ bool LLParser::parseUseListOrder(PerFunctionState *PFS) {
94729468
return sortUseListOrder(V, Indexes, Loc);
94739469
}
94749470

9475-
/// parseUseListOrderBB
9476-
/// ::= 'uselistorder_bb' @foo ',' %bar ',' UseListOrderIndexes
9477-
bool LLParser::parseUseListOrderBB() {
9478-
assert(Lex.getKind() == lltok::kw_uselistorder_bb);
9479-
SMLoc Loc = Lex.getLoc();
9480-
Lex.Lex();
9481-
9482-
ValID Fn, Label;
9483-
SmallVector<unsigned, 16> Indexes;
9484-
if (parseValID(Fn, /*PFS=*/nullptr) ||
9485-
parseToken(lltok::comma, "expected comma in uselistorder_bb directive") ||
9486-
parseValID(Label, /*PFS=*/nullptr) ||
9487-
parseToken(lltok::comma, "expected comma in uselistorder_bb directive") ||
9488-
parseUseListOrderIndexes(Indexes))
9489-
return true;
9490-
9491-
// Check the function.
9492-
GlobalValue *GV;
9493-
if (Fn.Kind == ValID::t_GlobalName)
9494-
GV = M->getNamedValue(Fn.StrVal);
9495-
else if (Fn.Kind == ValID::t_GlobalID)
9496-
GV = NumberedVals.get(Fn.UIntVal);
9497-
else
9498-
return error(Fn.Loc, "expected function name in uselistorder_bb");
9499-
if (!GV)
9500-
return error(Fn.Loc,
9501-
"invalid function forward reference in uselistorder_bb");
9502-
auto *F = dyn_cast<Function>(GV);
9503-
if (!F)
9504-
return error(Fn.Loc, "expected function name in uselistorder_bb");
9505-
if (F->isDeclaration())
9506-
return error(Fn.Loc, "invalid declaration in uselistorder_bb");
9507-
9508-
// Check the basic block.
9509-
if (Label.Kind == ValID::t_LocalID)
9510-
return error(Label.Loc, "invalid numeric label in uselistorder_bb");
9511-
if (Label.Kind != ValID::t_LocalName)
9512-
return error(Label.Loc, "expected basic block name in uselistorder_bb");
9513-
Value *V = F->getValueSymbolTable()->lookup(Label.StrVal);
9514-
if (!V)
9515-
return error(Label.Loc, "invalid basic block in uselistorder_bb");
9516-
if (!isa<BasicBlock>(V))
9517-
return error(Label.Loc, "expected basic block in uselistorder_bb");
9518-
9519-
return sortUseListOrder(V, Indexes, Loc);
9520-
}
9521-
95229471
/// ModuleEntry
95239472
/// ::= 'module' ':' '(' 'path' ':' STRINGCONSTANT ',' 'hash' ':' Hash ')'
95249473
/// Hash ::= '(' UInt32 ',' UInt32 ',' UInt32 ',' UInt32 ',' UInt32 ')'

‎llvm/lib/CodeGen/IndirectBrExpandPass.cpp‎

Lines changed: 2 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -135,23 +135,11 @@ bool runImpl(Function &F, const TargetLowering *TLI, DomTreeUpdater *DTU) {
135135
if (!IndirectBrSuccs.count(&BB))
136136
continue;
137137

138-
auto IsBlockAddressUse = [&](const Use &U) {
139-
return isa<BlockAddress>(U.getUser());
140-
};
141-
auto BlockAddressUseIt = llvm::find_if(BB.uses(), IsBlockAddressUse);
142-
if (BlockAddressUseIt == BB.use_end())
143-
continue;
144-
145-
assert(std::none_of(std::next(BlockAddressUseIt), BB.use_end(),
146-
IsBlockAddressUse) &&
147-
"There should only ever be a single blockaddress use because it is "
148-
"a constant and should be uniqued.");
149-
150-
auto *BA = cast<BlockAddress>(BlockAddressUseIt->getUser());
138+
auto *BA = BlockAddress::lookup(&BB);
151139

152140
// Skip if the constant was formed but ended up not being used (due to DCE
153141
// or whatever).
154-
if (!BA->isConstantUsed())
142+
if (!BA || !BA->isConstantUsed())
155143
continue;
156144

157145
// Compute the index we want to use for this basic block. We can't use zero

‎llvm/lib/IR/AsmWriter.cpp‎

Lines changed: 3 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -5038,20 +5038,11 @@ void AssemblyWriter::writeAllAttributeGroups() {
50385038

50395039
void AssemblyWriter::printUseListOrder(const Value *V,
50405040
ArrayRef<unsigned> Shuffle) {
5041-
bool IsInFunction = Machine.getFunction();
5042-
if (IsInFunction)
5041+
if (Machine.getFunction())
50435042
Out << " ";
50445043

5045-
Out << "uselistorder";
5046-
if (const BasicBlock *BB = IsInFunction ? nullptr : dyn_cast<BasicBlock>(V)) {
5047-
Out << "_bb ";
5048-
writeOperand(BB->getParent(), false);
5049-
Out << ", ";
5050-
writeOperand(BB, false);
5051-
} else {
5052-
Out << " ";
5053-
writeOperand(V, true);
5054-
}
5044+
Out << "uselistorder ";
5045+
writeOperand(V, true);
50555046

50565047
assert(Shuffle.size() >= 2 && "Shuffle too small");
50575048
Out << ", { " << llvm::interleaved(Shuffle) << " }\n";

‎llvm/lib/IR/BasicBlock.cpp‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -175,8 +175,7 @@ BasicBlock::~BasicBlock() {
175175
// is no indirect branch). Handle these cases by zapping the BlockAddress
176176
// nodes. There are no other possible uses at this point.
177177
if (hasAddressTaken()) {
178-
assert(!use_empty() && "There should be at least one blockaddress!");
179-
BlockAddress *BA = cast<BlockAddress>(user_back());
178+
BlockAddress *BA = BlockAddress::lookup(this);
180179

181180
Constant *Replacement = ConstantInt::get(Type::getInt32Ty(getContext()), 1);
182181
BA->replaceAllUsesWith(

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