//===- 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/BasicValueNumbering.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/iMemory.h"
-#include "llvm/InstrTypes.h"
+using namespace llvm;
// Register the ValueNumbering interface, providing a nice name to refer to.
static RegisterAnalysisGroup<ValueNumbering> X("Value Numbering");
ValueNumbering::~ValueNumbering() {}
//===----------------------------------------------------------------------===//
-// BasicValueNumbering Pass Implementation
+// Basic ValueNumbering Pass Implementation
//===----------------------------------------------------------------------===//
//
-// Because of the way .a files work, the implementation of the
-// BasicValueNumbering 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.
+// 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<BasicValueNumbering>
+ RegisterOpt<BasicVN>
X("basicvn", "Basic Value Numbering (default GVN impl)");
// Declare that we implement the ValueNumbering interface
- RegisterAnalysisGroup<ValueNumbering, BasicValueNumbering, true> Y;
-} // End of anonymous namespace
+ RegisterAnalysisGroup<ValueNumbering, BasicVN, true> Y;
-namespace {
- /// BVNImpl - Implement BasicValueNumbering in terms of a visitor class that
+ /// 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 visitBinaryOperator(Instruction &I);
+ void handleBinaryInst(Instruction &I);
+ void visitBinaryOperator(BinaryOperator &I) {
+ handleBinaryInst((Instruction&)I);
+ }
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitCastInst(CastInst &I);
- void visitShiftInst(ShiftInst &I) { visitBinaryOperator((Instruction&)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 BasicValueNumbering::getEqualNumberNodes(Value *V,
- std::vector<Value*> &RetVals) const {
+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!
for (Value::use_iterator UI = Op->use_begin(), UE = Op->use_end();
UI != UE; ++UI)
- if (Instruction *Other = dyn_cast<Instruction>(*UI))
- // Check to see if this new cast is not I, but has the same operand...
- if (Other != &I && Other->getOpcode() == I.getOpcode() &&
- Other->getOperand(0) == Op && // Is the operand the same?
- // Is it embeded in the same function? (This could be false if LHS
+ 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 that the types are the same, since this code handles casts...
- Other->getType() == I.getType()) {
-
+ // Check to see if this new cast is not I.
+ Other != &I) {
// These instructions are identical. Add to list...
RetVals.push_back(Other);
}
//
static inline bool isIdenticalBinaryInst(const Instruction &I1,
const Instruction *I2) {
- // Is it embeded in the same function? (This could be false if LHS
+ // 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())
I1.getOperand(1) == I2->getOperand(1))
return true;
- // If the instruction is commutative and associative, the instruction can
- // match if the operands are swapped!
+ // 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.getOpcode() == Instruction::Add ||
- I1.getOpcode() == Instruction::Mul ||
- I1.getOpcode() == Instruction::And ||
- I1.getOpcode() == Instruction::Or ||
- I1.getOpcode() == Instruction::Xor))
+ I1.isCommutative())
return true;
return false;
}
-void BVNImpl::visitBinaryOperator(Instruction &I) {
+void BVNImpl::handleBinaryInst(Instruction &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
Function *F = I.getParent()->getParent();
void BVNImpl::visitGetElementPtrInst(GetElementPtrInst &I) {
Value *Op = I.getOperand(0);
- Function *F = I.getParent()->getParent();
+
+ // Try to pick a local operand if possible instead of a constant or a global
+ // that might have a lot of uses.
+ for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
+ if (isa<Instruction>(I.getOperand(i)) || isa<Argument>(I.getOperand(i))) {
+ Op = I.getOperand(i);
+ break;
+ }
for (Value::use_iterator UI = Op->use_begin(), UE = Op->use_end();
UI != UE; ++UI)
RetVals.push_back(Other);
}
}
+
+void llvm::BasicValueNumberingStub() { }
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