mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 11:42:57 +01:00
f8077b7801
llvm-svn: 11308
194 lines
7.3 KiB
C++
194 lines
7.3 KiB
C++
//===- ValueNumbering.cpp - Value #'ing Implementation ----------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file was developed by the LLVM research group and 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.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#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"
|
|
|
|
namespace llvm {
|
|
|
|
// Register the ValueNumbering interface, providing a nice name to refer to.
|
|
static RegisterAnalysisGroup<ValueNumbering> X("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 BasicVN : public ImmutablePass, public ValueNumbering {
|
|
/// 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;
|
|
};
|
|
|
|
// Register this pass...
|
|
RegisterOpt<BasicVN>
|
|
X("basicvn", "Basic Value Numbering (default GVN impl)");
|
|
|
|
// Declare that we implement the ValueNumbering interface
|
|
RegisterAnalysisGroup<ValueNumbering, BasicVN, true> Y;
|
|
|
|
/// BVNImpl - Implement BasicVN in terms of a visitor class that
|
|
/// handles the different types of instructions as appropriate.
|
|
///
|
|
struct BVNImpl : public InstVisitor<BVNImpl> {
|
|
std::vector<Value*> &RetVals;
|
|
BVNImpl(std::vector<Value*> &RV) : RetVals(RV) {}
|
|
|
|
void handleBinaryInst(Instruction &I);
|
|
void visitBinaryOperator(BinaryOperator &I) {
|
|
handleBinaryInst((Instruction&)I);
|
|
}
|
|
void visitGetElementPtrInst(GetElementPtrInst &I);
|
|
void visitCastInst(CastInst &I);
|
|
void visitShiftInst(ShiftInst &I) { handleBinaryInst((Instruction&)I); }
|
|
void visitInstruction(Instruction &) {
|
|
// Cannot value number calls or terminator instructions...
|
|
}
|
|
};
|
|
}
|
|
|
|
// 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 types are the same, since this code handles casts...
|
|
if (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);
|
|
}
|
|
}
|
|
|
|
|
|
// 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;
|
|
|
|
// 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;
|
|
}
|
|
|
|
void BVNImpl::handleBinaryInst(Instruction &I) {
|
|
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
|
|
Function *F = I.getParent()->getParent();
|
|
|
|
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 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);
|
|
|
|
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 BasicValueNumberingStub() { }
|
|
|
|
} // End llvm namespace
|