//
// 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 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/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> X("Value Numbering");
+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
/// 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 {
+ 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.
virtual void getEqualNumberNodes(Value *V1,
std::vector<Value*> &RetVals) const;
};
+}
- // Register this pass...
- RegisterPass<BasicVN>
- X("basicvn", "Basic Value Numbering (default GVN impl)");
+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
- RegisterAnalysisGroup<ValueNumbering, BasicVN, true> Y;
+// 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 BVNImpl : public InstVisitor<BVNImpl> {
+ struct VISIBILITY_HIDDEN BVNImpl : public InstVisitor<BVNImpl> {
std::vector<Value*> &RetVals;
- BVNImpl(std::vector<Value*> &RV) : RetVals(RV) {}
+ 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); }
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() &&
+ // 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 &&
}
}
+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.
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))
// 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);
+ 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;
}
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