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Remove GCSE, ValueNumbering, and LoadValueNumbering. These have been deprecated for almost a year; it's finally time for them to go away.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54822 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2008-08-15 21:31:02 +00:00
parent 35115f92e4
commit 3688f268cb
10 changed files with 0 additions and 1153 deletions
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35
include/llvm/Analysis/LoadValueNumbering.h
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@ -1,35 +0,0 @@
//===- llvm/Analysis/LoadValueNumbering.h - Value # Load Insts --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a value numbering pass that value #'s load instructions.
// To do this, it finds lexically identical load instructions, and uses alias
// analysis to determine which loads are guaranteed to produce the same value.
//
// This pass builds off of another value numbering pass to implement value
// numbering for non-load instructions. It uses Alias Analysis so that it can
// disambiguate the load instructions. The more powerful these base analyses
// are, the more powerful the resultant analysis will be.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_LOAD_VALUE_NUMBERING_H
#define LLVM_ANALYSIS_LOAD_VALUE_NUMBERING_H
namespace llvm {
class FunctionPass;
/// createLoadValueNumberingPass - Create and return a new pass that implements
/// the ValueNumbering interface.
///
FunctionPass *createLoadValueNumberingPass();
} // End llvm namespace
#endif

7
include/llvm/Analysis/Passes.h
View File

@ -77,13 +77,6 @@ namespace llvm {
//
ModulePass *createAndersensPass();
//===--------------------------------------------------------------------===//
//
// createBasicVNPass - This pass walks SSA def-use chains to trivially
// identify lexically identical expressions.
//
ImmutablePass *createBasicVNPass();
//===--------------------------------------------------------------------===//
//
// createProfileLoaderPass - This pass loads information from a profile dump

75
include/llvm/Analysis/ValueNumbering.h
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@ -1,75 +0,0 @@
//===- llvm/Analysis/ValueNumbering.h - Value #'ing Interface ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the abstract ValueNumbering interface, which is used as the
// common interface used by all clients of value numbering information, and
// implemented by all value numbering implementations.
//
// Implementations of this interface must implement the various virtual methods,
// which automatically provides functionality for the entire suite of client
// APIs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_VALUE_NUMBERING_H
#define LLVM_ANALYSIS_VALUE_NUMBERING_H
#include <vector>
#include "llvm/Pass.h"
#include "llvm/System/IncludeFile.h"
namespace llvm {
class Value;
class Instruction;
struct ValueNumbering {
static char ID; // Class identification, replacement for typeinfo
virtual ~ValueNumbering(); // We want to be subclassed
/// getEqualNumberNodes - Return nodes with the same value number as the
/// specified Value. This fills in the argument vector with any equal values.
///
virtual void getEqualNumberNodes(Value *V1,
std::vector<Value*> &RetVals) const = 0;
///===-------------------------------------------------------------------===//
/// Interfaces to update value numbering analysis information as the client
/// changes the program.
///
/// deleteValue - This method should be called whenever an LLVM Value is
/// deleted from the program, for example when an instruction is found to be
/// redundant and is eliminated.
///
virtual void deleteValue(Value *V) {}
/// copyValue - This method should be used whenever a preexisting value in the
/// program is copied or cloned, introducing a new value. Note that analysis
/// implementations should tolerate clients that use this method to introduce
/// the same value multiple times: if the analysis already knows about a
/// value, it should ignore the request.
///
virtual void copyValue(Value *From, Value *To) {}
/// replaceWithNewValue - This method is the obvious combination of the two
/// above, and it provided as a helper to simplify client code.
///
void replaceWithNewValue(Value *Old, Value *New) {
copyValue(Old, New);
deleteValue(Old);
}
};
} // End llvm namespace
// Force any file including this header to get the implementation as well
FORCE_DEFINING_FILE_TO_BE_LINKED(BasicValueNumbering)
#endif

4
include/llvm/LinkAllPasses.h
View File

@ -18,7 +18,6 @@
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/FindUsedTypes.h"
#include "llvm/Analysis/IntervalPartition.h"
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Analysis/LoopVR.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/PostDominators.h"
@ -50,7 +49,6 @@ namespace {
(void) llvm::createStructRetPromotionPass();
(void) llvm::createBasicAliasAnalysisPass();
(void) llvm::createLibCallAliasAnalysisPass(0);
(void) llvm::createBasicVNPass();
(void) llvm::createBlockPlacementPass();
(void) llvm::createBlockProfilerPass();
(void) llvm::createBreakCriticalEdgesPass();
@ -65,7 +63,6 @@ namespace {
(void) llvm::createEdgeProfilerPass();
(void) llvm::createFunctionInliningPass();
(void) llvm::createFunctionProfilerPass();
(void) llvm::createGCSEPass();
(void) llvm::createGlobalDCEPass();
(void) llvm::createGlobalOptimizerPass();
(void) llvm::createGlobalsModRefPass();
@ -77,7 +74,6 @@ namespace {
(void) llvm::createInternalizePass(false);
(void) llvm::createLCSSAPass();
(void) llvm::createLICMPass();
(void) llvm::createLoadValueNumberingPass();
(void) llvm::createLoopExtractorPass();
(void) llvm::createLoopSimplifyPass();
(void) llvm::createLoopStrengthReducePass();

9
include/llvm/Transforms/Scalar.h
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@ -76,15 +76,6 @@ FunctionPass *createAggressiveDCEPass();
//
FunctionPass *createScalarReplAggregatesPass(signed Threshold = -1);
//===----------------------------------------------------------------------===//
//
// GCSE - This pass is designed to be a very quick global transformation that
// eliminates global common subexpressions from a function. It does this by
// examining the SSA value graph of the function, instead of doing slow
// bit-vector computations.
//
FunctionPass *createGCSEPass();
//===----------------------------------------------------------------------===//
//
// InductionVariableSimplify - Transform induction variables in a program to all

530
lib/Analysis/LoadValueNumbering.cpp
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@ -1,530 +0,0 @@
//===- LoadValueNumbering.cpp - Load Value #'ing Implementation -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a value numbering pass that value numbers load and call
// instructions. To do this, it finds lexically identical load instructions,
// and uses alias analysis to determine which loads are guaranteed to produce
// the same value. To value number call instructions, it looks for calls to
// functions that do not write to memory which do not have intervening
// instructions that clobber the memory that is read from.
//
// This pass builds off of another value numbering pass to implement value
// numbering for non-load and non-call instructions. It uses Alias Analysis so
// that it can disambiguate the load instructions. The more powerful these base
// analyses are, the more powerful the resultant value numbering will be.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/Analysis/ValueNumbering.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Target/TargetData.h"
#include <set>
#include <algorithm>
using namespace llvm;
namespace {
// FIXME: This should not be a FunctionPass.
struct VISIBILITY_HIDDEN LoadVN : public FunctionPass, public ValueNumbering {
static char ID; // Class identification, replacement for typeinfo
LoadVN() : FunctionPass((intptr_t)&ID) {}
/// Pass Implementation stuff. This doesn't do any analysis.
///
bool runOnFunction(Function &) { return false; }
/// getAnalysisUsage - Does not modify anything. It uses Value Numbering
/// and Alias Analysis.
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
/// getEqualNumberNodes - Return nodes with the same value number as the
/// specified Value. This fills in the argument vector with any equal
/// values.
///
virtual void getEqualNumberNodes(Value *V1,
std::vector<Value*> &RetVals) const;
/// deleteValue - This method should be called whenever an LLVM Value is
/// deleted from the program, for example when an instruction is found to be
/// redundant and is eliminated.
///
virtual void deleteValue(Value *V) {
getAnalysis<AliasAnalysis>().deleteValue(V);
}
/// copyValue - This method should be used whenever a preexisting value in
/// the program is copied or cloned, introducing a new value. Note that
/// analysis implementations should tolerate clients that use this method to
/// introduce the same value multiple times: if the analysis already knows
/// about a value, it should ignore the request.
///
virtual void copyValue(Value *From, Value *To) {
getAnalysis<AliasAnalysis>().copyValue(From, To);
}
/// getCallEqualNumberNodes - Given a call instruction, find other calls
/// that have the same value number.
void getCallEqualNumberNodes(CallInst *CI,
std::vector<Value*> &RetVals) const;
};
}
char LoadVN::ID = 0;
// Register this pass...
static RegisterPass<LoadVN>
X("load-vn", "Load Value Numbering", false, true);
// Declare that we implement the ValueNumbering interface
static RegisterAnalysisGroup<ValueNumbering> Y(X);
FunctionPass *llvm::createLoadValueNumberingPass() { return new LoadVN(); }
/// getAnalysisUsage - Does not modify anything. It uses Value Numbering and
/// Alias Analysis.
///
void LoadVN::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequiredTransitive<AliasAnalysis>();
AU.addRequired<ValueNumbering>();
AU.addRequiredTransitive<DominatorTree>();
AU.addRequiredTransitive<TargetData>();
}
static bool isPathTransparentTo(BasicBlock *CurBlock, BasicBlock *Dom,
Value *Ptr, unsigned Size, AliasAnalysis &AA,
std::set<BasicBlock*> &Visited,
std::map<BasicBlock*, bool> &TransparentBlocks){
// If we have already checked out this path, or if we reached our destination,
// stop searching, returning success.
if (CurBlock == Dom || !Visited.insert(CurBlock).second)
return true;
// Check whether this block is known transparent or not.
std::map<BasicBlock*, bool>::iterator TBI =
TransparentBlocks.find(CurBlock);
if (TBI == TransparentBlocks.end()) {
// If this basic block can modify the memory location, then the path is not
// transparent!
if (AA.canBasicBlockModify(*CurBlock, Ptr, Size)) {
TransparentBlocks.insert(TBI, std::make_pair(CurBlock, false));
return false;
}
TransparentBlocks.insert(TBI, std::make_pair(CurBlock, true));
} else if (!TBI->second)
// This block is known non-transparent, so that path can't be either.
return false;
// The current block is known to be transparent. The entire path is
// transparent if all of the predecessors paths to the parent is also
// transparent to the memory location.
for (pred_iterator PI = pred_begin(CurBlock), E = pred_end(CurBlock);
PI != E; ++PI)
if (!isPathTransparentTo(*PI, Dom, Ptr, Size, AA, Visited,
TransparentBlocks))
return false;
return true;
}
/// getCallEqualNumberNodes - Given a call instruction, find other calls that
/// have the same value number.
void LoadVN::getCallEqualNumberNodes(CallInst *CI,
std::vector<Value*> &RetVals) const {
Function *CF = CI->getCalledFunction();
if (CF == 0) return; // Indirect call.
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
AliasAnalysis::ModRefBehavior MRB = AA.getModRefBehavior(CI);
if (MRB != AliasAnalysis::DoesNotAccessMemory &&
MRB != AliasAnalysis::OnlyReadsMemory)
return; // Nothing we can do for now.
// Scan all of the arguments of the function, looking for one that is not
// global. In particular, we would prefer to have an argument or instruction
// operand to chase the def-use chains of.
Value *Op = CF;
for (User::op_iterator i = CI->op_begin() + 1, e = CI->op_end(); i != e; ++i)
if (isa<Argument>(*i) ||
isa<Instruction>(*i)) {
Op = *i;
break;
}
// Identify all lexically identical calls in this function.
std::vector<CallInst*> IdenticalCalls;
Function *CIFunc = CI->getParent()->getParent();
for (Value::use_iterator UI = Op->use_begin(), E = Op->use_end(); UI != E;
++UI)
if (CallInst *C = dyn_cast<CallInst>(*UI))
if (C->getNumOperands() == CI->getNumOperands() &&
C->getOperand(0) == CI->getOperand(0) &&
C->getParent()->getParent() == CIFunc && C != CI) {
bool AllOperandsEqual = true;
for (User::op_iterator i = CI->op_begin() + 1, j = C->op_begin() + 1,
e = CI->op_end(); i != e; ++i, ++j)
if (*j != *i) {
AllOperandsEqual = false;
break;
}
if (AllOperandsEqual)
IdenticalCalls.push_back(C);
}
if (IdenticalCalls.empty()) return;
// Eliminate duplicates, which could occur if we chose a value that is passed
// into a call site multiple times.
std::sort(IdenticalCalls.begin(), IdenticalCalls.end());
IdenticalCalls.erase(std::unique(IdenticalCalls.begin(),IdenticalCalls.end()),
IdenticalCalls.end());
// If the call reads memory, we must make sure that there are no stores
// between the calls in question.
//
// FIXME: This should use mod/ref information. What we really care about it
// whether an intervening instruction could modify memory that is read, not
// ANY memory.
//
if (MRB == AliasAnalysis::OnlyReadsMemory) {
DominatorTree &DT = getAnalysis<DominatorTree>();
BasicBlock *CIBB = CI->getParent();
for (unsigned i = 0; i != IdenticalCalls.size(); ++i) {
CallInst *C = IdenticalCalls[i];
bool CantEqual = false;
if (DT.dominates(CIBB, C->getParent())) {
// FIXME: we currently only handle the case where both calls are in the
// same basic block.
if (CIBB != C->getParent()) {
CantEqual = true;
} else {
Instruction *First = CI, *Second = C;
if (!DT.dominates(CI, C))
std::swap(First, Second);
// Scan the instructions between the calls, checking for stores or
// calls to dangerous functions.
BasicBlock::iterator I = First;
for (++First; I != BasicBlock::iterator(Second); ++I) {
if (isa<StoreInst>(I)) {
// FIXME: We could use mod/ref information to make this much
// better!
CantEqual = true;
break;
} else if (CallInst *CI = dyn_cast<CallInst>(I)) {
if (!AA.onlyReadsMemory(CI)) {
CantEqual = true;
break;
}
} else if (I->mayWriteToMemory()) {
CantEqual = true;
break;
}
}
}
} else if (DT.dominates(C->getParent(), CIBB)) {
// FIXME: We could implement this, but we don't for now.
CantEqual = true;
} else {
// FIXME: if one doesn't dominate the other, we can't tell yet.
CantEqual = true;
}
if (CantEqual) {
// This call does not produce the same value as the one in the query.
std::swap(IdenticalCalls[i--], IdenticalCalls.back());
IdenticalCalls.pop_back();
}
}
}
// Any calls that are identical and not destroyed will produce equal values!
for (unsigned i = 0, e = IdenticalCalls.size(); i != e; ++i)
RetVals.push_back(IdenticalCalls[i]);
}
// getEqualNumberNodes - Return nodes with the same value number as the
// specified Value. This fills in the argument vector with any equal values.
//
void LoadVN::getEqualNumberNodes(Value *V,
std::vector<Value*> &RetVals) const {
// If the alias analysis has any must alias information to share with us, we
// can definitely use it.
if (isa<PointerType>(V->getType()))
getAnalysis<AliasAnalysis>().getMustAliases(V, RetVals);
if (!isa<LoadInst>(V)) {
if (CallInst *CI = dyn_cast<CallInst>(V))
getCallEqualNumberNodes(CI, RetVals);
// Not a load instruction? Just chain to the base value numbering
// implementation to satisfy the request...
assert(&getAnalysis<ValueNumbering>() != (ValueNumbering*)this &&
"getAnalysis() returned this!");
return getAnalysis<ValueNumbering>().getEqualNumberNodes(V, RetVals);
}
// Volatile loads cannot be replaced with the value of other loads.
LoadInst *LI = cast<LoadInst>(V);
if (LI->isVolatile())
return getAnalysis<ValueNumbering>().getEqualNumberNodes(V, RetVals);
Value *LoadPtr = LI->getOperand(0);
BasicBlock *LoadBB = LI->getParent();
Function *F = LoadBB->getParent();
// Find out how many bytes of memory are loaded by the load instruction...
unsigned LoadSize = getAnalysis<TargetData>().getTypeStoreSize(LI->getType());
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
// Figure out if the load is invalidated from the entry of the block it is in
// until the actual instruction. This scans the block backwards from LI. If
// we see any candidate load or store instructions, then we know that the
// candidates have the same value # as LI.
bool LoadInvalidatedInBBBefore = false;
for (BasicBlock::iterator I = LI; I != LoadBB->begin(); ) {
--I;
if (I == LoadPtr) {
// If we run into an allocation of the value being loaded, then the
// contents are not initialized.
if (isa<AllocationInst>(I))
RetVals.push_back(UndefValue::get(LI->getType()));
// Otherwise, since this is the definition of what we are loading, this
// loaded value cannot occur before this block.
LoadInvalidatedInBBBefore = true;
break;
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
// If this instruction is a candidate load before LI, we know there are no
// invalidating instructions between it and LI, so they have the same
// value number.
if (LI->getOperand(0) == LoadPtr && !LI->isVolatile())
RetVals.push_back(I);
}
if (AA.getModRefInfo(I, LoadPtr, LoadSize) & AliasAnalysis::Mod) {
// If the invalidating instruction is a store, and its in our candidate
// set, then we can do store-load forwarding: the load has the same value
// # as the stored value.
if (StoreInst *SI = dyn_cast<StoreInst>(I))
if (SI->getOperand(1) == LoadPtr)
RetVals.push_back(I->getOperand(0));
LoadInvalidatedInBBBefore = true;
break;
}
}
// Figure out if the load is invalidated between the load and the exit of the
// block it is defined in. While we are scanning the current basic block, if
// we see any candidate loads, then we know they have the same value # as LI.
//
bool LoadInvalidatedInBBAfter = false;
{
BasicBlock::iterator I = LI;
for (++I; I != LoadBB->end(); ++I) {
// If this instruction is a load, then this instruction returns the same
// value as LI.
if (isa<LoadInst>(I) && cast<LoadInst>(I)->getOperand(0) == LoadPtr)
RetVals.push_back(I);
if (AA.getModRefInfo(I, LoadPtr, LoadSize) & AliasAnalysis::Mod) {
LoadInvalidatedInBBAfter = true;
break;
}
}
}
// If the pointer is clobbered on entry and on exit to the function, there is
// no need to do any global analysis at all.
if (LoadInvalidatedInBBBefore && LoadInvalidatedInBBAfter)
return;
// Now that we know the value is not neccesarily killed on entry or exit to
// the BB, find out how many load and store instructions (to this location)
// live in each BB in the function.
//
std::map<BasicBlock*, unsigned> CandidateLoads;
std::set<BasicBlock*> CandidateStores;
for (Value::use_iterator UI = LoadPtr->use_begin(), UE = LoadPtr->use_end();
UI != UE; ++UI)
if (LoadInst *Cand = dyn_cast<LoadInst>(*UI)) {// Is a load of source?
if (Cand->getParent()->getParent() == F && // In the same function?
// Not in LI's block?
Cand->getParent() != LoadBB && !Cand->isVolatile())
++CandidateLoads[Cand->getParent()]; // Got one.
} else if (StoreInst *Cand = dyn_cast<StoreInst>(*UI)) {
if (Cand->getParent()->getParent() == F && !Cand->isVolatile() &&
Cand->getOperand(1) == LoadPtr) // It's a store THROUGH the ptr.
CandidateStores.insert(Cand->getParent());
}
// Get dominators.
DominatorTree &DT = getAnalysis<DominatorTree>();
// TransparentBlocks - For each basic block the load/store is alive across,
// figure out if the pointer is invalidated or not. If it is invalidated, the
// boolean is set to false, if it's not it is set to true. If we don't know
// yet, the entry is not in the map.
std::map<BasicBlock*, bool> TransparentBlocks;
// Loop over all of the basic blocks that also load the value. If the value
// is live across the CFG from the source to destination blocks, and if the
// value is not invalidated in either the source or destination blocks, add it
// to the equivalence sets.
for (std::map<BasicBlock*, unsigned>::iterator
I = CandidateLoads.begin(), E = CandidateLoads.end(); I != E; ++I) {
bool CantEqual = false;
// Right now we only can handle cases where one load dominates the other.
// FIXME: generalize this!
BasicBlock *BB1 = I->first, *BB2 = LoadBB;
if (DT.dominates(BB1, BB2)) {
// The other load dominates LI. If the loaded value is killed entering
// the LoadBB block, we know the load is not live.
if (LoadInvalidatedInBBBefore)
CantEqual = true;
} else if (DT.dominates(BB2, BB1)) {
std::swap(BB1, BB2); // Canonicalize
// LI dominates the other load. If the loaded value is killed exiting
// the LoadBB block, we know the load is not live.
if (LoadInvalidatedInBBAfter)
CantEqual = true;
} else {
// None of these loads can VN the same.
CantEqual = true;
}
if (!CantEqual) {
// Ok, at this point, we know that BB1 dominates BB2, and that there is
// nothing in the LI block that kills the loaded value. Check to see if
// the value is live across the CFG.
std::set<BasicBlock*> Visited;
for (pred_iterator PI = pred_begin(BB2), E = pred_end(BB2); PI!=E; ++PI)
if (!isPathTransparentTo(*PI, BB1, LoadPtr, LoadSize, AA,
Visited, TransparentBlocks)) {
// None of these loads can VN the same.
CantEqual = true;
break;
}
}
// If the loads can equal so far, scan the basic block that contains the
// loads under consideration to see if they are invalidated in the block.
// For any loads that are not invalidated, add them to the equivalence
// set!
if (!CantEqual) {
unsigned NumLoads = I->second;
if (BB1 == LoadBB) {
// If LI dominates the block in question, check to see if any of the
// loads in this block are invalidated before they are reached.
for (BasicBlock::iterator BBI = I->first->begin(); ; ++BBI) {
if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
if (LI->getOperand(0) == LoadPtr && !LI->isVolatile()) {
// The load is in the set!
RetVals.push_back(BBI);
if (--NumLoads == 0) break; // Found last load to check.
}
} else if (AA.getModRefInfo(BBI, LoadPtr, LoadSize)
& AliasAnalysis::Mod) {
// If there is a modifying instruction, nothing below it will value
// # the same.
break;
}
}
} else {
// If the block dominates LI, make sure that the loads in the block are
// not invalidated before the block ends.
BasicBlock::iterator BBI = I->first->end();
while (1) {
--BBI;
if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
if (LI->getOperand(0) == LoadPtr && !LI->isVolatile()) {
// The load is the same as this load!
RetVals.push_back(BBI);
if (--NumLoads == 0) break; // Found all of the laods.
}
} else if (AA.getModRefInfo(BBI, LoadPtr, LoadSize)
& AliasAnalysis::Mod) {
// If there is a modifying instruction, nothing above it will value
// # the same.
break;
}
}
}
}
}
// Handle candidate stores. If the loaded location is clobbered on entrance
// to the LoadBB, no store outside of the LoadBB can value number equal, so
// quick exit.
if (LoadInvalidatedInBBBefore)
return;
// Stores in the load-bb are handled above.
CandidateStores.erase(LoadBB);
for (std::set<BasicBlock*>::iterator I = CandidateStores.begin(),
E = CandidateStores.end(); I != E; ++I)
if (DT.dominates(*I, LoadBB)) {
BasicBlock *StoreBB = *I;
// Check to see if the path from the store to the load is transparent
// w.r.t. the memory location.
bool CantEqual = false;
std::set<BasicBlock*> Visited;
for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB);
PI != E; ++PI)
if (!isPathTransparentTo(*PI, StoreBB, LoadPtr, LoadSize, AA,
Visited, TransparentBlocks)) {
// None of these stores can VN the same.
CantEqual = true;
break;
}
Visited.clear();
if (!CantEqual) {
// Okay, the path from the store block to the load block is clear, and
// we know that there are no invalidating instructions from the start
// of the load block to the load itself. Now we just scan the store
// block.
BasicBlock::iterator BBI = StoreBB->end();
while (1) {
assert(BBI != StoreBB->begin() &&
"There is a store in this block of the pointer, but the store"
" doesn't mod the address being stored to?? Must be a bug in"
" the alias analysis implementation!");
--BBI;
if (AA.getModRefInfo(BBI, LoadPtr, LoadSize) & AliasAnalysis::Mod) {
// If the invalidating instruction is one of the candidates,
// then it provides the value the load loads.
if (StoreInst *SI = dyn_cast<StoreInst>(BBI))
if (SI->getOperand(1) == LoadPtr)
RetVals.push_back(SI->getOperand(0));
break;
}
}
}
}
}

286
lib/Analysis/ValueNumbering.cpp
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@ -1,286 +0,0 @@
//===- ValueNumbering.cpp - Value #'ing Implementation ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the non-abstract Value Numbering methods as well as a
// default implementation for the analysis group.
//
// The ValueNumbering analysis pass is mostly deprecated. It is only used by the
// Global Common Subexpression Elimination pass, which is deprecated by the
// Global Value Numbering pass (which does its value numbering on its own).
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ValueNumbering.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/BasicBlock.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/Support/Compiler.h"
using namespace llvm;
char ValueNumbering::ID = 0;
// Register the ValueNumbering interface, providing a nice name to refer to.
static RegisterAnalysisGroup<ValueNumbering> V("Value Numbering");
/// ValueNumbering destructor: DO NOT move this to the header file for
/// ValueNumbering or else clients of the ValueNumbering class may not depend on
/// the ValueNumbering.o file in the current .a file, causing alias analysis
/// support to not be included in the tool correctly!
///
ValueNumbering::~ValueNumbering() {}
//===----------------------------------------------------------------------===//
// Basic ValueNumbering Pass Implementation
//===----------------------------------------------------------------------===//
//
// Because of the way .a files work, the implementation of the BasicVN class
// MUST be in the ValueNumbering file itself, or else we run the risk of
// ValueNumbering being used, but the default implementation not being linked
// into the tool that uses it. As such, we register and implement the class
// here.
//
namespace {
/// BasicVN - This class is the default implementation of the ValueNumbering
/// interface. It walks the SSA def-use chains to trivially identify
/// lexically identical expressions. This does not require any ahead of time
/// analysis, so it is a very fast default implementation.
///
struct VISIBILITY_HIDDEN BasicVN
: public ImmutablePass, public ValueNumbering {
static char ID; // Class identification, replacement for typeinfo
BasicVN() : ImmutablePass((intptr_t)&ID) {}
/// getEqualNumberNodes - Return nodes with the same value number as the
/// specified Value. This fills in the argument vector with any equal
/// values.
///
/// This is where our implementation is.
///
virtual void getEqualNumberNodes(Value *V1,
std::vector<Value*> &RetVals) const;
};
}
char BasicVN::ID = 0;
// Register this pass...
static RegisterPass<BasicVN>
X("basicvn", "Basic Value Numbering (default GVN impl)", false, true);
// Declare that we implement the ValueNumbering interface
static RegisterAnalysisGroup<ValueNumbering, true> Y(X);
namespace {
/// BVNImpl - Implement BasicVN in terms of a visitor class that
/// handles the different types of instructions as appropriate.
///
struct VISIBILITY_HIDDEN BVNImpl : public InstVisitor<BVNImpl> {
std::vector<Value*> &RetVals;
explicit BVNImpl(std::vector<Value*> &RV) : RetVals(RV) {}
void visitCastInst(CastInst &I);
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitCmpInst(CmpInst &I);
void handleBinaryInst(Instruction &I);
void visitBinaryOperator(Instruction &I) { handleBinaryInst(I); }
void visitShiftInst(Instruction &I) { handleBinaryInst(I); }
void visitExtractElementInst(Instruction &I) { handleBinaryInst(I); }
void handleTernaryInst(Instruction &I);
void visitSelectInst(Instruction &I) { handleTernaryInst(I); }
void visitInsertElementInst(Instruction &I) { handleTernaryInst(I); }
void visitShuffleVectorInst(Instruction &I) { handleTernaryInst(I); }
void visitInstruction(Instruction &) {
// Cannot value number calls or terminator instructions.
}
};
}
ImmutablePass *llvm::createBasicVNPass() { return new BasicVN(); }
// getEqualNumberNodes - Return nodes with the same value number as the
// specified Value. This fills in the argument vector with any equal values.
//
void BasicVN::getEqualNumberNodes(Value *V, std::vector<Value*> &RetVals) const{
assert(V->getType() != Type::VoidTy &&
"Can only value number non-void values!");
// We can only handle the case where I is an instruction!
if (Instruction *I = dyn_cast<Instruction>(V))
BVNImpl(RetVals).visit(I);
}
void BVNImpl::visitCastInst(CastInst &CI) {
Instruction &I = (Instruction&)CI;
Value *Op = I.getOperand(0);
Function *F = I.getParent()->getParent();
for (Value::use_iterator UI = Op->use_begin(), UE = Op->use_end();
UI != UE; ++UI)
if (CastInst *Other = dyn_cast<CastInst>(*UI))
// Check that the opcode is the same
if (Other->getOpcode() == Instruction::CastOps(I.getOpcode()) &&
// Check that the destination types are the same
Other->getType() == I.getType() &&
// Is it embedded in the same function? (This could be false if LHS
// is a constant or global!)
Other->getParent()->getParent() == F &&
// Check to see if this new cast is not I.
Other != &I) {
// These instructions are identical. Add to list...
RetVals.push_back(Other);
}
}
void BVNImpl::visitCmpInst(CmpInst &CI1) {
Value *LHS = CI1.getOperand(0);
for (Value::use_iterator UI = LHS->use_begin(), UE = LHS->use_end();
UI != UE; ++UI)
if (CmpInst *CI2 = dyn_cast<CmpInst>(*UI))
// Check to see if this compare instruction is not CI, but same opcode,
// same predicate, and in the same function.
if (CI2 != &CI1 && CI2->getOpcode() == CI1.getOpcode() &&
CI2->getPredicate() == CI1.getPredicate() &&
CI2->getParent()->getParent() == CI1.getParent()->getParent())
// If the operands are the same
if ((CI2->getOperand(0) == CI1.getOperand(0) &&
CI2->getOperand(1) == CI1.getOperand(1)) ||
// Or the compare is commutative and the operands are reversed
(CI1.isCommutative() &&
CI2->getOperand(0) == CI1.getOperand(1) &&
CI2->getOperand(1) == CI1.getOperand(0)))
// Then the instructiosn are identical, add to list.
RetVals.push_back(CI2);
}
// isIdenticalBinaryInst - Return true if the two binary instructions are
// identical.
//
static inline bool isIdenticalBinaryInst(const Instruction &I1,
const Instruction *I2) {
// Is it embedded in the same function? (This could be false if LHS
// is a constant or global!)
if (I1.getOpcode() != I2->getOpcode() ||
I1.getParent()->getParent() != I2->getParent()->getParent())
return false;
// If they are CmpInst instructions, check their predicates
if (CmpInst *CI1 = dyn_cast<CmpInst>(&const_cast<Instruction&>(I1)))
if (CI1->getPredicate() != cast<CmpInst>(I2)->getPredicate())
return false;
// They are identical if both operands are the same!
if (I1.getOperand(0) == I2->getOperand(0) &&
I1.getOperand(1) == I2->getOperand(1))
return true;
// If the instruction is commutative, the instruction can match if the
// operands are swapped!
//
if ((I1.getOperand(0) == I2->getOperand(1) &&
I1.getOperand(1) == I2->getOperand(0)) &&
I1.isCommutative())
return true;
return false;
}
// isIdenticalTernaryInst - Return true if the two ternary instructions are
// identical.
//
static inline bool isIdenticalTernaryInst(const Instruction &I1,
const Instruction *I2) {
// Is it embedded in the same function? (This could be false if LHS
// is a constant or global!)
if (I1.getParent()->getParent() != I2->getParent()->getParent())
return false;
// They are identical if all operands are the same!
return I1.getOperand(0) == I2->getOperand(0) &&
I1.getOperand(1) == I2->getOperand(1) &&
I1.getOperand(2) == I2->getOperand(2);
}
void BVNImpl::handleBinaryInst(Instruction &I) {
Value *LHS = I.getOperand(0);
for (Value::use_iterator UI = LHS->use_begin(), UE = LHS->use_end();
UI != UE; ++UI)
if (Instruction *Other = dyn_cast<Instruction>(*UI))
// Check to see if this new binary operator is not I, but same operand...
if (Other != &I && isIdenticalBinaryInst(I, Other)) {
// These instructions are identical. Handle the situation.
RetVals.push_back(Other);
}
}
// IdenticalComplexInst - Return true if the two instructions are the same, by
// using a brute force comparison. This is useful for instructions with an
// arbitrary number of arguments.
//
static inline bool IdenticalComplexInst(const Instruction *I1,
const Instruction *I2) {
assert(I1->getOpcode() == I2->getOpcode());
// Equal if they are in the same function...
return I1->getParent()->getParent() == I2->getParent()->getParent() &&
// And return the same type...
I1->getType() == I2->getType() &&
// And have the same number of operands...
I1->getNumOperands() == I2->getNumOperands() &&
// And all of the operands are equal.
std::equal(I1->op_begin(), I1->op_end(), I2->op_begin());
}
void BVNImpl::visitGetElementPtrInst(GetElementPtrInst &I) {
Value *Op = I.getOperand(0);
// Try to pick a local operand if possible instead of a constant or a global
// that might have a lot of uses.
for (User::op_iterator i = I.op_begin() + 1, e = I.op_end(); i != e; ++i)
if (isa<Instruction>(*i) || isa<Argument>(*i)) {
Op = *i;
break;
}
for (Value::use_iterator UI = Op->use_begin(), UE = Op->use_end();
UI != UE; ++UI)
if (GetElementPtrInst *Other = dyn_cast<GetElementPtrInst>(*UI))
// Check to see if this new getelementptr is not I, but same operand...
if (Other != &I && IdenticalComplexInst(&I, Other)) {
// These instructions are identical. Handle the situation.
RetVals.push_back(Other);
}
}
void BVNImpl::handleTernaryInst(Instruction &I) {
Value *Op0 = I.getOperand(0);
Instruction *OtherInst;
for (Value::use_iterator UI = Op0->use_begin(), UE = Op0->use_end();
UI != UE; ++UI)
if ((OtherInst = dyn_cast<Instruction>(*UI)) &&
OtherInst->getOpcode() == I.getOpcode()) {
// Check to see if this new select is not I, but has the same operands.
if (OtherInst != &I && isIdenticalTernaryInst(I, OtherInst)) {
// These instructions are identical. Handle the situation.
RetVals.push_back(OtherInst);
}
}
}
// Ensure that users of ValueNumbering.h will link with this file
DEFINING_FILE_FOR(BasicValueNumbering)

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lib/Transforms/Scalar/GCSE.cpp
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//===-- GCSE.cpp - SSA-based Global Common Subexpression Elimination ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass is designed to be a very quick global transformation that
// eliminates global common subexpressions from a function. It does this by
// using an existing value numbering analysis pass to identify the common
// subexpressions, eliminating them when possible.
//
// This pass is deprecated by the Global Value Numbering pass (which does a
// better job with its own value numbering).
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "gcse"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
#include "llvm/Type.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ValueNumbering.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumInstRemoved, "Number of instructions removed");
STATISTIC(NumLoadRemoved, "Number of loads removed");
STATISTIC(NumCallRemoved, "Number of calls removed");
STATISTIC(NumNonInsts , "Number of instructions removed due "
"to non-instruction values");
STATISTIC(NumArgsRepl , "Number of function arguments replaced "
"with constant values");
namespace {
struct VISIBILITY_HIDDEN GCSE : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
GCSE() : FunctionPass((intptr_t)&ID) {}
virtual bool runOnFunction(Function &F);
private:
void ReplaceInstructionWith(Instruction *I, Value *V);
// This transformation requires dominator and immediate dominator info
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<DominatorTree>();
AU.addRequired<ValueNumbering>();
}
};
}
char GCSE::ID = 0;
static RegisterPass<GCSE>
X("gcse", "Global Common Subexpression Elimination");
// createGCSEPass - The public interface to this file...
FunctionPass *llvm::createGCSEPass() { return new GCSE(); }
// GCSE::runOnFunction - This is the main transformation entry point for a
// function.
//
bool GCSE::runOnFunction(Function &F) {
bool Changed = false;
// Get pointers to the analysis results that we will be using...
DominatorTree &DT = getAnalysis<DominatorTree>();
ValueNumbering &VN = getAnalysis<ValueNumbering>();
std::vector<Value*> EqualValues;
// Check for value numbers of arguments. If the value numbering
// implementation can prove that an incoming argument is a constant or global
// value address, substitute it, making the argument dead.
for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end(); AI != E;++AI)
if (!AI->use_empty()) {
VN.getEqualNumberNodes(AI, EqualValues);
if (!EqualValues.empty()) {
for (unsigned i = 0, e = EqualValues.size(); i != e; ++i)
if (isa<Constant>(EqualValues[i])) {
AI->replaceAllUsesWith(EqualValues[i]);
++NumArgsRepl;
Changed = true;
break;
}
EqualValues.clear();
}
}
// Traverse the CFG of the function in dominator order, so that we see each
// instruction after we see its operands.
for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
E = df_end(DT.getRootNode()); DI != E; ++DI) {
BasicBlock *BB = DI->getBlock();
// Remember which instructions we've seen in this basic block as we scan.
std::set<Instruction*> BlockInsts;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
Instruction *Inst = I++;
if (Constant *C = ConstantFoldInstruction(Inst)) {
ReplaceInstructionWith(Inst, C);
} else if (Inst->getType() != Type::VoidTy) {
// If this instruction computes a value, try to fold together common
// instructions that compute it.
//
VN.getEqualNumberNodes(Inst, EqualValues);
// If this instruction computes a value that is already computed
// elsewhere, try to recycle the old value.
if (!EqualValues.empty()) {
if (Inst == &*BB->begin())
I = BB->end();
else {
I = Inst; --I;
}
// First check to see if we were able to value number this instruction
// to a non-instruction value. If so, prefer that value over other
// instructions which may compute the same thing.
for (unsigned i = 0, e = EqualValues.size(); i != e; ++i)
if (!isa<Instruction>(EqualValues[i])) {
++NumNonInsts; // Keep track of # of insts repl with values
// Change all users of Inst to use the replacement and remove it
// from the program.
ReplaceInstructionWith(Inst, EqualValues[i]);
Inst = 0;
EqualValues.clear(); // don't enter the next loop
break;
}
// If there were no non-instruction values that this instruction
// produces, find a dominating instruction that produces the same
// value. If we find one, use it's value instead of ours.
for (unsigned i = 0, e = EqualValues.size(); i != e; ++i) {
Instruction *OtherI = cast<Instruction>(EqualValues[i]);
bool Dominates = false;
if (OtherI->getParent() == BB)
Dominates = BlockInsts.count(OtherI);
else
Dominates = DT.dominates(OtherI->getParent(), BB);
if (Dominates) {
// Okay, we found an instruction with the same value as this one
// and that dominates this one. Replace this instruction with the
// specified one.
ReplaceInstructionWith(Inst, OtherI);
Inst = 0;
break;
}
}
EqualValues.clear();
if (Inst) {
I = Inst; ++I; // Deleted no instructions
} else if (I == BB->end()) { // Deleted first instruction
I = BB->begin();
} else { // Deleted inst in middle of block.
++I;
}
}
if (Inst)
BlockInsts.insert(Inst);
}
}
}
// When the worklist is empty, return whether or not we changed anything...
return Changed;
}
void GCSE::ReplaceInstructionWith(Instruction *I, Value *V) {
if (isa<LoadInst>(I))
++NumLoadRemoved; // Keep track of loads eliminated
if (isa<CallInst>(I))
++NumCallRemoved; // Keep track of calls eliminated
++NumInstRemoved; // Keep track of number of insts eliminated
// Update value numbering
getAnalysis<ValueNumbering>().deleteValue(I);
I->replaceAllUsesWith(V);
if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
// Removing an invoke instruction requires adding a branch to the normal
// destination and removing PHI node entries in the exception destination.
BranchInst::Create(II->getNormalDest(), II);
II->getUnwindDest()->removePredecessor(II->getParent());
}
// Erase the instruction from the program.
I->eraseFromParent();
}

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tools/llvm-ld/Optimize.cpp
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#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/Verifier.h"

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tools/lto/LTOCodeGenerator.cpp
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#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/CodeGen/FileWriters.h"
#include "llvm/Target/SubtargetFeature.h"
#include "llvm/Target/TargetOptions.h"