forked from OSchip/llvm-project
2705 lines
93 KiB
C++
2705 lines
93 KiB
C++
//===-- PredicateSimplifier.cpp - Path Sensitive Simplifier ---------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Path-sensitive optimizer. In a branch where x == y, replace uses of
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// x with y. Permits further optimization, such as the elimination of
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// the unreachable call:
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//
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// void test(int *p, int *q)
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// {
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// if (p != q)
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// return;
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//
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// if (*p != *q)
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// foo(); // unreachable
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// }
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//
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//===----------------------------------------------------------------------===//
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//
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// The InequalityGraph focusses on four properties; equals, not equals,
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// less-than and less-than-or-equals-to. The greater-than forms are also held
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// just to allow walking from a lesser node to a greater one. These properties
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// are stored in a lattice; LE can become LT or EQ, NE can become LT or GT.
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//
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// These relationships define a graph between values of the same type. Each
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// Value is stored in a map table that retrieves the associated Node. This
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// is how EQ relationships are stored; the map contains pointers from equal
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// Value to the same node. The node contains a most canonical Value* form
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// and the list of known relationships with other nodes.
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//
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// If two nodes are known to be inequal, then they will contain pointers to
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// each other with an "NE" relationship. If node getNode(%x) is less than
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// getNode(%y), then the %x node will contain <%y, GT> and %y will contain
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// <%x, LT>. This allows us to tie nodes together into a graph like this:
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//
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// %a < %b < %c < %d
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//
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// with four nodes representing the properties. The InequalityGraph provides
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// querying with "isRelatedBy" and mutators "addEquality" and "addInequality".
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// To find a relationship, we start with one of the nodes any binary search
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// through its list to find where the relationships with the second node start.
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// Then we iterate through those to find the first relationship that dominates
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// our context node.
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//
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// To create these properties, we wait until a branch or switch instruction
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// implies that a particular value is true (or false). The VRPSolver is
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// responsible for analyzing the variable and seeing what new inferences
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// can be made from each property. For example:
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//
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// %P = icmp ne i32* %ptr, null
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// %a = and i1 %P, %Q
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// br i1 %a label %cond_true, label %cond_false
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//
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// For the true branch, the VRPSolver will start with %a EQ true and look at
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// the definition of %a and find that it can infer that %P and %Q are both
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// true. From %P being true, it can infer that %ptr NE null. For the false
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// branch it can't infer anything from the "and" instruction.
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//
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// Besides branches, we can also infer properties from instruction that may
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// have undefined behaviour in certain cases. For example, the dividend of
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// a division may never be zero. After the division instruction, we may assume
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// that the dividend is not equal to zero.
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//
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//===----------------------------------------------------------------------===//
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//
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// The ValueRanges class stores the known integer bounds of a Value. When we
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// encounter i8 %a u< %b, the ValueRanges stores that %a = [1, 255] and
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// %b = [0, 254].
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//
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// It never stores an empty range, because that means that the code is
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// unreachable. It never stores a single-element range since that's an equality
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// relationship and better stored in the InequalityGraph, nor an empty range
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// since that is better stored in UnreachableBlocks.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "predsimplify"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Pass.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SetOperations.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Assembly/Writer.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/ConstantRange.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/InstVisitor.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include <algorithm>
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#include <deque>
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#include <stack>
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using namespace llvm;
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STATISTIC(NumVarsReplaced, "Number of argument substitutions");
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STATISTIC(NumInstruction , "Number of instructions removed");
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STATISTIC(NumSimple , "Number of simple replacements");
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STATISTIC(NumBlocks , "Number of blocks marked unreachable");
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STATISTIC(NumSnuggle , "Number of comparisons snuggled");
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static const ConstantRange empty(1, false);
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namespace {
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class DomTreeDFS {
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public:
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class Node {
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friend class DomTreeDFS;
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public:
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typedef std::vector<Node *>::iterator iterator;
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typedef std::vector<Node *>::const_iterator const_iterator;
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unsigned getDFSNumIn() const { return DFSin; }
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unsigned getDFSNumOut() const { return DFSout; }
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BasicBlock *getBlock() const { return BB; }
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iterator begin() { return Children.begin(); }
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iterator end() { return Children.end(); }
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const_iterator begin() const { return Children.begin(); }
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const_iterator end() const { return Children.end(); }
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bool dominates(const Node *N) const {
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return DFSin <= N->DFSin && DFSout >= N->DFSout;
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}
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bool DominatedBy(const Node *N) const {
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return N->dominates(this);
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}
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/// Sorts by the number of descendants. With this, you can iterate
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/// through a sorted list and the first matching entry is the most
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/// specific match for your basic block. The order provided is stable;
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/// DomTreeDFS::Nodes with the same number of descendants are sorted by
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/// DFS in number.
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bool operator<(const Node &N) const {
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unsigned spread = DFSout - DFSin;
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unsigned N_spread = N.DFSout - N.DFSin;
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if (spread == N_spread) return DFSin < N.DFSin;
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return spread < N_spread;
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}
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bool operator>(const Node &N) const { return N < *this; }
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private:
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unsigned DFSin, DFSout;
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BasicBlock *BB;
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std::vector<Node *> Children;
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};
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// XXX: this may be slow. Instead of using "new" for each node, consider
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// putting them in a vector to keep them contiguous.
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explicit DomTreeDFS(DominatorTree *DT) {
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std::stack<std::pair<Node *, DomTreeNode *> > S;
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Entry = new Node;
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Entry->BB = DT->getRootNode()->getBlock();
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S.push(std::make_pair(Entry, DT->getRootNode()));
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NodeMap[Entry->BB] = Entry;
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while (!S.empty()) {
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std::pair<Node *, DomTreeNode *> &Pair = S.top();
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Node *N = Pair.first;
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DomTreeNode *DTNode = Pair.second;
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S.pop();
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for (DomTreeNode::iterator I = DTNode->begin(), E = DTNode->end();
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I != E; ++I) {
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Node *NewNode = new Node;
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NewNode->BB = (*I)->getBlock();
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N->Children.push_back(NewNode);
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S.push(std::make_pair(NewNode, *I));
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NodeMap[NewNode->BB] = NewNode;
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}
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}
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renumber();
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#ifndef NDEBUG
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DEBUG(dump());
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#endif
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}
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#ifndef NDEBUG
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virtual
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#endif
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~DomTreeDFS() {
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std::stack<Node *> S;
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S.push(Entry);
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while (!S.empty()) {
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Node *N = S.top(); S.pop();
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for (Node::iterator I = N->begin(), E = N->end(); I != E; ++I)
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S.push(*I);
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delete N;
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}
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}
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/// getRootNode - This returns the entry node for the CFG of the function.
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Node *getRootNode() const { return Entry; }
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/// getNodeForBlock - return the node for the specified basic block.
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Node *getNodeForBlock(BasicBlock *BB) const {
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if (!NodeMap.count(BB)) return 0;
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return const_cast<DomTreeDFS*>(this)->NodeMap[BB];
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}
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/// dominates - returns true if the basic block for I1 dominates that of
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/// the basic block for I2. If the instructions belong to the same basic
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/// block, the instruction first instruction sequentially in the block is
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/// considered dominating.
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bool dominates(Instruction *I1, Instruction *I2) {
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BasicBlock *BB1 = I1->getParent(),
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*BB2 = I2->getParent();
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if (BB1 == BB2) {
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if (isa<TerminatorInst>(I1)) return false;
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if (isa<TerminatorInst>(I2)) return true;
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if ( isa<PHINode>(I1) && !isa<PHINode>(I2)) return true;
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if (!isa<PHINode>(I1) && isa<PHINode>(I2)) return false;
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for (BasicBlock::const_iterator I = BB2->begin(), E = BB2->end();
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I != E; ++I) {
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if (&*I == I1) return true;
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else if (&*I == I2) return false;
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}
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assert(!"Instructions not found in parent BasicBlock?");
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} else {
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Node *Node1 = getNodeForBlock(BB1),
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*Node2 = getNodeForBlock(BB2);
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return Node1 && Node2 && Node1->dominates(Node2);
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}
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return false; // Not reached
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}
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private:
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/// renumber - calculates the depth first search numberings and applies
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/// them onto the nodes.
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void renumber() {
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std::stack<std::pair<Node *, Node::iterator> > S;
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unsigned n = 0;
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Entry->DFSin = ++n;
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S.push(std::make_pair(Entry, Entry->begin()));
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while (!S.empty()) {
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std::pair<Node *, Node::iterator> &Pair = S.top();
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Node *N = Pair.first;
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Node::iterator &I = Pair.second;
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if (I == N->end()) {
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N->DFSout = ++n;
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S.pop();
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} else {
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Node *Next = *I++;
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Next->DFSin = ++n;
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S.push(std::make_pair(Next, Next->begin()));
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}
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}
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}
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#ifndef NDEBUG
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virtual void dump() const {
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dump(errs());
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}
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void dump(raw_ostream &os) const {
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os << "Predicate simplifier DomTreeDFS: \n";
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dump(Entry, 0, os);
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os << "\n\n";
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}
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void dump(Node *N, int depth, raw_ostream &os) const {
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++depth;
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for (int i = 0; i < depth; ++i) { os << " "; }
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os << "[" << depth << "] ";
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os << N->getBlock()->getNameStr() << " (" << N->getDFSNumIn()
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<< ", " << N->getDFSNumOut() << ")\n";
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for (Node::iterator I = N->begin(), E = N->end(); I != E; ++I)
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dump(*I, depth, os);
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}
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#endif
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Node *Entry;
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std::map<BasicBlock *, Node *> NodeMap;
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};
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// SLT SGT ULT UGT EQ
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// 0 1 0 1 0 -- GT 10
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// 0 1 0 1 1 -- GE 11
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// 0 1 1 0 0 -- SGTULT 12
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// 0 1 1 0 1 -- SGEULE 13
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// 0 1 1 1 0 -- SGT 14
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// 0 1 1 1 1 -- SGE 15
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// 1 0 0 1 0 -- SLTUGT 18
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// 1 0 0 1 1 -- SLEUGE 19
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// 1 0 1 0 0 -- LT 20
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// 1 0 1 0 1 -- LE 21
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// 1 0 1 1 0 -- SLT 22
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// 1 0 1 1 1 -- SLE 23
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// 1 1 0 1 0 -- UGT 26
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// 1 1 0 1 1 -- UGE 27
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// 1 1 1 0 0 -- ULT 28
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// 1 1 1 0 1 -- ULE 29
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// 1 1 1 1 0 -- NE 30
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enum LatticeBits {
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EQ_BIT = 1, UGT_BIT = 2, ULT_BIT = 4, SGT_BIT = 8, SLT_BIT = 16
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};
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enum LatticeVal {
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GT = SGT_BIT | UGT_BIT,
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GE = GT | EQ_BIT,
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LT = SLT_BIT | ULT_BIT,
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LE = LT | EQ_BIT,
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NE = SLT_BIT | SGT_BIT | ULT_BIT | UGT_BIT,
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SGTULT = SGT_BIT | ULT_BIT,
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SGEULE = SGTULT | EQ_BIT,
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SLTUGT = SLT_BIT | UGT_BIT,
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SLEUGE = SLTUGT | EQ_BIT,
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ULT = SLT_BIT | SGT_BIT | ULT_BIT,
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UGT = SLT_BIT | SGT_BIT | UGT_BIT,
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SLT = SLT_BIT | ULT_BIT | UGT_BIT,
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SGT = SGT_BIT | ULT_BIT | UGT_BIT,
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SLE = SLT | EQ_BIT,
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SGE = SGT | EQ_BIT,
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ULE = ULT | EQ_BIT,
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UGE = UGT | EQ_BIT
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};
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#ifndef NDEBUG
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/// validPredicate - determines whether a given value is actually a lattice
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/// value. Only used in assertions or debugging.
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static bool validPredicate(LatticeVal LV) {
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switch (LV) {
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case GT: case GE: case LT: case LE: case NE:
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case SGTULT: case SGT: case SGEULE:
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case SLTUGT: case SLT: case SLEUGE:
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case ULT: case UGT:
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case SLE: case SGE: case ULE: case UGE:
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return true;
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default:
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return false;
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}
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}
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#endif
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/// reversePredicate - reverse the direction of the inequality
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static LatticeVal reversePredicate(LatticeVal LV) {
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unsigned reverse = LV ^ (SLT_BIT|SGT_BIT|ULT_BIT|UGT_BIT); //preserve EQ_BIT
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if ((reverse & (SLT_BIT|SGT_BIT)) == 0)
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reverse |= (SLT_BIT|SGT_BIT);
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if ((reverse & (ULT_BIT|UGT_BIT)) == 0)
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reverse |= (ULT_BIT|UGT_BIT);
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LatticeVal Rev = static_cast<LatticeVal>(reverse);
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assert(validPredicate(Rev) && "Failed reversing predicate.");
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return Rev;
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}
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/// ValueNumbering stores the scope-specific value numbers for a given Value.
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class ValueNumbering {
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/// VNPair is a tuple of {Value, index number, DomTreeDFS::Node}. It
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/// includes the comparison operators necessary to allow you to store it
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/// in a sorted vector.
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class VNPair {
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public:
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Value *V;
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unsigned index;
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DomTreeDFS::Node *Subtree;
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VNPair(Value *V, unsigned index, DomTreeDFS::Node *Subtree)
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: V(V), index(index), Subtree(Subtree) {}
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bool operator==(const VNPair &RHS) const {
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return V == RHS.V && Subtree == RHS.Subtree;
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}
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bool operator<(const VNPair &RHS) const {
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if (V != RHS.V) return V < RHS.V;
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return *Subtree < *RHS.Subtree;
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}
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bool operator<(Value *RHS) const {
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return V < RHS;
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}
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bool operator>(Value *RHS) const {
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return V > RHS;
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}
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friend bool operator<(Value *RHS, const VNPair &pair) {
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return pair.operator>(RHS);
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}
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};
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typedef std::vector<VNPair> VNMapType;
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VNMapType VNMap;
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/// The canonical choice for value number at index.
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std::vector<Value *> Values;
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DomTreeDFS *DTDFS;
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public:
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#ifndef NDEBUG
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virtual ~ValueNumbering() {}
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virtual void dump() {
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print(errs());
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}
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void print(raw_ostream &os) {
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for (unsigned i = 1; i <= Values.size(); ++i) {
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os << i << " = ";
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WriteAsOperand(os, Values[i-1]);
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os << " {";
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for (unsigned j = 0; j < VNMap.size(); ++j) {
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if (VNMap[j].index == i) {
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WriteAsOperand(os, VNMap[j].V);
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os << " (" << VNMap[j].Subtree->getDFSNumIn() << ") ";
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}
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}
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os << "}\n";
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}
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}
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#endif
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/// compare - returns true if V1 is a better canonical value than V2.
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bool compare(Value *V1, Value *V2) const {
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if (isa<Constant>(V1))
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return !isa<Constant>(V2);
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else if (isa<Constant>(V2))
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return false;
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else if (isa<Argument>(V1))
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return !isa<Argument>(V2);
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else if (isa<Argument>(V2))
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return false;
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Instruction *I1 = dyn_cast<Instruction>(V1);
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Instruction *I2 = dyn_cast<Instruction>(V2);
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if (!I1 || !I2)
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return V1->getNumUses() < V2->getNumUses();
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return DTDFS->dominates(I1, I2);
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}
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ValueNumbering(DomTreeDFS *DTDFS) : DTDFS(DTDFS) {}
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/// valueNumber - finds the value number for V under the Subtree. If
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/// there is no value number, returns zero.
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unsigned valueNumber(Value *V, DomTreeDFS::Node *Subtree) {
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if (!(isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) ||
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V->getType() == Type::getVoidTy(V->getContext())) return 0;
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VNMapType::iterator E = VNMap.end();
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VNPair pair(V, 0, Subtree);
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VNMapType::iterator I = std::lower_bound(VNMap.begin(), E, pair);
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while (I != E && I->V == V) {
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if (I->Subtree->dominates(Subtree))
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return I->index;
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++I;
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}
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return 0;
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}
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/// getOrInsertVN - always returns a value number, creating it if necessary.
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unsigned getOrInsertVN(Value *V, DomTreeDFS::Node *Subtree) {
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if (unsigned n = valueNumber(V, Subtree))
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return n;
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else
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return newVN(V);
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}
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/// newVN - creates a new value number. Value V must not already have a
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/// value number assigned.
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unsigned newVN(Value *V) {
|
|
assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) &&
|
|
"Bad Value for value numbering.");
|
|
assert(V->getType() != Type::getVoidTy(V->getContext()) &&
|
|
"Won't value number a void value");
|
|
|
|
Values.push_back(V);
|
|
|
|
VNPair pair = VNPair(V, Values.size(), DTDFS->getRootNode());
|
|
VNMapType::iterator I = std::lower_bound(VNMap.begin(), VNMap.end(), pair);
|
|
assert((I == VNMap.end() || value(I->index) != V) &&
|
|
"Attempt to create a duplicate value number.");
|
|
VNMap.insert(I, pair);
|
|
|
|
return Values.size();
|
|
}
|
|
|
|
/// value - returns the Value associated with a value number.
|
|
Value *value(unsigned index) const {
|
|
assert(index != 0 && "Zero index is reserved for not found.");
|
|
assert(index <= Values.size() && "Index out of range.");
|
|
return Values[index-1];
|
|
}
|
|
|
|
/// canonicalize - return a Value that is equal to V under Subtree.
|
|
Value *canonicalize(Value *V, DomTreeDFS::Node *Subtree) {
|
|
if (isa<Constant>(V)) return V;
|
|
|
|
if (unsigned n = valueNumber(V, Subtree))
|
|
return value(n);
|
|
else
|
|
return V;
|
|
}
|
|
|
|
/// addEquality - adds that value V belongs to the set of equivalent
|
|
/// values defined by value number n under Subtree.
|
|
void addEquality(unsigned n, Value *V, DomTreeDFS::Node *Subtree) {
|
|
assert(canonicalize(value(n), Subtree) == value(n) &&
|
|
"Node's 'canonical' choice isn't best within this subtree.");
|
|
|
|
// Suppose that we are given "%x -> node #1 (%y)". The problem is that
|
|
// we may already have "%z -> node #2 (%x)" somewhere above us in the
|
|
// graph. We need to find those edges and add "%z -> node #1 (%y)"
|
|
// to keep the lookups canonical.
|
|
|
|
std::vector<Value *> ToRepoint(1, V);
|
|
|
|
if (unsigned Conflict = valueNumber(V, Subtree)) {
|
|
for (VNMapType::iterator I = VNMap.begin(), E = VNMap.end();
|
|
I != E; ++I) {
|
|
if (I->index == Conflict && I->Subtree->dominates(Subtree))
|
|
ToRepoint.push_back(I->V);
|
|
}
|
|
}
|
|
|
|
for (std::vector<Value *>::iterator VI = ToRepoint.begin(),
|
|
VE = ToRepoint.end(); VI != VE; ++VI) {
|
|
Value *V = *VI;
|
|
|
|
VNPair pair(V, n, Subtree);
|
|
VNMapType::iterator B = VNMap.begin(), E = VNMap.end();
|
|
VNMapType::iterator I = std::lower_bound(B, E, pair);
|
|
if (I != E && I->V == V && I->Subtree == Subtree)
|
|
I->index = n; // Update best choice
|
|
else
|
|
VNMap.insert(I, pair); // New Value
|
|
|
|
// XXX: we currently don't have to worry about updating values with
|
|
// more specific Subtrees, but we will need to for PHI node support.
|
|
|
|
#ifndef NDEBUG
|
|
Value *V_n = value(n);
|
|
if (isa<Constant>(V) && isa<Constant>(V_n)) {
|
|
assert(V == V_n && "Constant equals different constant?");
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/// remove - removes all references to value V.
|
|
void remove(Value *V) {
|
|
VNMapType::iterator B = VNMap.begin(), E = VNMap.end();
|
|
VNPair pair(V, 0, DTDFS->getRootNode());
|
|
VNMapType::iterator J = std::upper_bound(B, E, pair);
|
|
VNMapType::iterator I = J;
|
|
|
|
while (I != B && (I == E || I->V == V)) --I;
|
|
|
|
VNMap.erase(I, J);
|
|
}
|
|
};
|
|
|
|
/// The InequalityGraph stores the relationships between values.
|
|
/// Each Value in the graph is assigned to a Node. Nodes are pointer
|
|
/// comparable for equality. The caller is expected to maintain the logical
|
|
/// consistency of the system.
|
|
///
|
|
/// The InequalityGraph class may invalidate Node*s after any mutator call.
|
|
/// @brief The InequalityGraph stores the relationships between values.
|
|
class InequalityGraph {
|
|
ValueNumbering &VN;
|
|
DomTreeDFS::Node *TreeRoot;
|
|
|
|
InequalityGraph(); // DO NOT IMPLEMENT
|
|
InequalityGraph(InequalityGraph &); // DO NOT IMPLEMENT
|
|
public:
|
|
InequalityGraph(ValueNumbering &VN, DomTreeDFS::Node *TreeRoot)
|
|
: VN(VN), TreeRoot(TreeRoot) {}
|
|
|
|
class Node;
|
|
|
|
/// An Edge is contained inside a Node making one end of the edge implicit
|
|
/// and contains a pointer to the other end. The edge contains a lattice
|
|
/// value specifying the relationship and an DomTreeDFS::Node specifying
|
|
/// the root in the dominator tree to which this edge applies.
|
|
class Edge {
|
|
public:
|
|
Edge(unsigned T, LatticeVal V, DomTreeDFS::Node *ST)
|
|
: To(T), LV(V), Subtree(ST) {}
|
|
|
|
unsigned To;
|
|
LatticeVal LV;
|
|
DomTreeDFS::Node *Subtree;
|
|
|
|
bool operator<(const Edge &edge) const {
|
|
if (To != edge.To) return To < edge.To;
|
|
return *Subtree < *edge.Subtree;
|
|
}
|
|
|
|
bool operator<(unsigned to) const {
|
|
return To < to;
|
|
}
|
|
|
|
bool operator>(unsigned to) const {
|
|
return To > to;
|
|
}
|
|
|
|
friend bool operator<(unsigned to, const Edge &edge) {
|
|
return edge.operator>(to);
|
|
}
|
|
};
|
|
|
|
/// A single node in the InequalityGraph. This stores the canonical Value
|
|
/// for the node, as well as the relationships with the neighbours.
|
|
///
|
|
/// @brief A single node in the InequalityGraph.
|
|
class Node {
|
|
friend class InequalityGraph;
|
|
|
|
typedef SmallVector<Edge, 4> RelationsType;
|
|
RelationsType Relations;
|
|
|
|
// TODO: can this idea improve performance?
|
|
//friend class std::vector<Node>;
|
|
//Node(Node &N) { RelationsType.swap(N.RelationsType); }
|
|
|
|
public:
|
|
typedef RelationsType::iterator iterator;
|
|
typedef RelationsType::const_iterator const_iterator;
|
|
|
|
#ifndef NDEBUG
|
|
virtual ~Node() {}
|
|
virtual void dump() const {
|
|
dump(errs());
|
|
}
|
|
private:
|
|
void dump(raw_ostream &os) const {
|
|
static const std::string names[32] =
|
|
{ "000000", "000001", "000002", "000003", "000004", "000005",
|
|
"000006", "000007", "000008", "000009", " >", " >=",
|
|
" s>u<", "s>=u<=", " s>", " s>=", "000016", "000017",
|
|
" s<u>", "s<=u>=", " <", " <=", " s<", " s<=",
|
|
"000024", "000025", " u>", " u>=", " u<", " u<=",
|
|
" !=", "000031" };
|
|
for (Node::const_iterator NI = begin(), NE = end(); NI != NE; ++NI) {
|
|
os << names[NI->LV] << " " << NI->To
|
|
<< " (" << NI->Subtree->getDFSNumIn() << "), ";
|
|
}
|
|
}
|
|
public:
|
|
#endif
|
|
|
|
iterator begin() { return Relations.begin(); }
|
|
iterator end() { return Relations.end(); }
|
|
const_iterator begin() const { return Relations.begin(); }
|
|
const_iterator end() const { return Relations.end(); }
|
|
|
|
iterator find(unsigned n, DomTreeDFS::Node *Subtree) {
|
|
iterator E = end();
|
|
for (iterator I = std::lower_bound(begin(), E, n);
|
|
I != E && I->To == n; ++I) {
|
|
if (Subtree->DominatedBy(I->Subtree))
|
|
return I;
|
|
}
|
|
return E;
|
|
}
|
|
|
|
const_iterator find(unsigned n, DomTreeDFS::Node *Subtree) const {
|
|
const_iterator E = end();
|
|
for (const_iterator I = std::lower_bound(begin(), E, n);
|
|
I != E && I->To == n; ++I) {
|
|
if (Subtree->DominatedBy(I->Subtree))
|
|
return I;
|
|
}
|
|
return E;
|
|
}
|
|
|
|
/// update - updates the lattice value for a given node, creating a new
|
|
/// entry if one doesn't exist. The new lattice value must not be
|
|
/// inconsistent with any previously existing value.
|
|
void update(unsigned n, LatticeVal R, DomTreeDFS::Node *Subtree) {
|
|
assert(validPredicate(R) && "Invalid predicate.");
|
|
|
|
Edge edge(n, R, Subtree);
|
|
iterator B = begin(), E = end();
|
|
iterator I = std::lower_bound(B, E, edge);
|
|
|
|
iterator J = I;
|
|
while (J != E && J->To == n) {
|
|
if (Subtree->DominatedBy(J->Subtree))
|
|
break;
|
|
++J;
|
|
}
|
|
|
|
if (J != E && J->To == n) {
|
|
edge.LV = static_cast<LatticeVal>(J->LV & R);
|
|
assert(validPredicate(edge.LV) && "Invalid union of lattice values.");
|
|
|
|
if (edge.LV == J->LV)
|
|
return; // This update adds nothing new.
|
|
}
|
|
|
|
if (I != B) {
|
|
// We also have to tighten any edge beneath our update.
|
|
for (iterator K = I - 1; K->To == n; --K) {
|
|
if (K->Subtree->DominatedBy(Subtree)) {
|
|
LatticeVal LV = static_cast<LatticeVal>(K->LV & edge.LV);
|
|
assert(validPredicate(LV) && "Invalid union of lattice values");
|
|
K->LV = LV;
|
|
}
|
|
if (K == B) break;
|
|
}
|
|
}
|
|
|
|
// Insert new edge at Subtree if it isn't already there.
|
|
if (I == E || I->To != n || Subtree != I->Subtree)
|
|
Relations.insert(I, edge);
|
|
}
|
|
};
|
|
|
|
private:
|
|
|
|
std::vector<Node> Nodes;
|
|
|
|
public:
|
|
/// node - returns the node object at a given value number. The pointer
|
|
/// returned may be invalidated on the next call to node().
|
|
Node *node(unsigned index) {
|
|
assert(VN.value(index)); // This triggers the necessary checks.
|
|
if (Nodes.size() < index) Nodes.resize(index);
|
|
return &Nodes[index-1];
|
|
}
|
|
|
|
/// isRelatedBy - true iff n1 op n2
|
|
bool isRelatedBy(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree,
|
|
LatticeVal LV) {
|
|
if (n1 == n2) return LV & EQ_BIT;
|
|
|
|
Node *N1 = node(n1);
|
|
Node::iterator I = N1->find(n2, Subtree), E = N1->end();
|
|
if (I != E) return (I->LV & LV) == I->LV;
|
|
|
|
return false;
|
|
}
|
|
|
|
// The add* methods assume that your input is logically valid and may
|
|
// assertion-fail or infinitely loop if you attempt a contradiction.
|
|
|
|
/// addInequality - Sets n1 op n2.
|
|
/// It is also an error to call this on an inequality that is already true.
|
|
void addInequality(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree,
|
|
LatticeVal LV1) {
|
|
assert(n1 != n2 && "A node can't be inequal to itself.");
|
|
|
|
if (LV1 != NE)
|
|
assert(!isRelatedBy(n1, n2, Subtree, reversePredicate(LV1)) &&
|
|
"Contradictory inequality.");
|
|
|
|
// Suppose we're adding %n1 < %n2. Find all the %a < %n1 and
|
|
// add %a < %n2 too. This keeps the graph fully connected.
|
|
if (LV1 != NE) {
|
|
// Break up the relationship into signed and unsigned comparison parts.
|
|
// If the signed parts of %a op1 %n1 match that of %n1 op2 %n2, and
|
|
// op1 and op2 aren't NE, then add %a op3 %n2. The new relationship
|
|
// should have the EQ_BIT iff it's set for both op1 and op2.
|
|
|
|
unsigned LV1_s = LV1 & (SLT_BIT|SGT_BIT);
|
|
unsigned LV1_u = LV1 & (ULT_BIT|UGT_BIT);
|
|
|
|
for (Node::iterator I = node(n1)->begin(), E = node(n1)->end(); I != E; ++I) {
|
|
if (I->LV != NE && I->To != n2) {
|
|
|
|
DomTreeDFS::Node *Local_Subtree = NULL;
|
|
if (Subtree->DominatedBy(I->Subtree))
|
|
Local_Subtree = Subtree;
|
|
else if (I->Subtree->DominatedBy(Subtree))
|
|
Local_Subtree = I->Subtree;
|
|
|
|
if (Local_Subtree) {
|
|
unsigned new_relationship = 0;
|
|
LatticeVal ILV = reversePredicate(I->LV);
|
|
unsigned ILV_s = ILV & (SLT_BIT|SGT_BIT);
|
|
unsigned ILV_u = ILV & (ULT_BIT|UGT_BIT);
|
|
|
|
if (LV1_s != (SLT_BIT|SGT_BIT) && ILV_s == LV1_s)
|
|
new_relationship |= ILV_s;
|
|
if (LV1_u != (ULT_BIT|UGT_BIT) && ILV_u == LV1_u)
|
|
new_relationship |= ILV_u;
|
|
|
|
if (new_relationship) {
|
|
if ((new_relationship & (SLT_BIT|SGT_BIT)) == 0)
|
|
new_relationship |= (SLT_BIT|SGT_BIT);
|
|
if ((new_relationship & (ULT_BIT|UGT_BIT)) == 0)
|
|
new_relationship |= (ULT_BIT|UGT_BIT);
|
|
if ((LV1 & EQ_BIT) && (ILV & EQ_BIT))
|
|
new_relationship |= EQ_BIT;
|
|
|
|
LatticeVal NewLV = static_cast<LatticeVal>(new_relationship);
|
|
|
|
node(I->To)->update(n2, NewLV, Local_Subtree);
|
|
node(n2)->update(I->To, reversePredicate(NewLV), Local_Subtree);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
for (Node::iterator I = node(n2)->begin(), E = node(n2)->end(); I != E; ++I) {
|
|
if (I->LV != NE && I->To != n1) {
|
|
DomTreeDFS::Node *Local_Subtree = NULL;
|
|
if (Subtree->DominatedBy(I->Subtree))
|
|
Local_Subtree = Subtree;
|
|
else if (I->Subtree->DominatedBy(Subtree))
|
|
Local_Subtree = I->Subtree;
|
|
|
|
if (Local_Subtree) {
|
|
unsigned new_relationship = 0;
|
|
unsigned ILV_s = I->LV & (SLT_BIT|SGT_BIT);
|
|
unsigned ILV_u = I->LV & (ULT_BIT|UGT_BIT);
|
|
|
|
if (LV1_s != (SLT_BIT|SGT_BIT) && ILV_s == LV1_s)
|
|
new_relationship |= ILV_s;
|
|
|
|
if (LV1_u != (ULT_BIT|UGT_BIT) && ILV_u == LV1_u)
|
|
new_relationship |= ILV_u;
|
|
|
|
if (new_relationship) {
|
|
if ((new_relationship & (SLT_BIT|SGT_BIT)) == 0)
|
|
new_relationship |= (SLT_BIT|SGT_BIT);
|
|
if ((new_relationship & (ULT_BIT|UGT_BIT)) == 0)
|
|
new_relationship |= (ULT_BIT|UGT_BIT);
|
|
if ((LV1 & EQ_BIT) && (I->LV & EQ_BIT))
|
|
new_relationship |= EQ_BIT;
|
|
|
|
LatticeVal NewLV = static_cast<LatticeVal>(new_relationship);
|
|
|
|
node(n1)->update(I->To, NewLV, Local_Subtree);
|
|
node(I->To)->update(n1, reversePredicate(NewLV), Local_Subtree);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
node(n1)->update(n2, LV1, Subtree);
|
|
node(n2)->update(n1, reversePredicate(LV1), Subtree);
|
|
}
|
|
|
|
/// remove - removes a node from the graph by removing all references to
|
|
/// and from it.
|
|
void remove(unsigned n) {
|
|
Node *N = node(n);
|
|
for (Node::iterator NI = N->begin(), NE = N->end(); NI != NE; ++NI) {
|
|
Node::iterator Iter = node(NI->To)->find(n, TreeRoot);
|
|
do {
|
|
node(NI->To)->Relations.erase(Iter);
|
|
Iter = node(NI->To)->find(n, TreeRoot);
|
|
} while (Iter != node(NI->To)->end());
|
|
}
|
|
N->Relations.clear();
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
virtual ~InequalityGraph() {}
|
|
virtual void dump() {
|
|
dump(errs());
|
|
}
|
|
|
|
void dump(raw_ostream &os) {
|
|
for (unsigned i = 1; i <= Nodes.size(); ++i) {
|
|
os << i << " = {";
|
|
node(i)->dump(os);
|
|
os << "}\n";
|
|
}
|
|
}
|
|
#endif
|
|
};
|
|
|
|
class VRPSolver;
|
|
|
|
/// ValueRanges tracks the known integer ranges and anti-ranges of the nodes
|
|
/// in the InequalityGraph.
|
|
class ValueRanges {
|
|
ValueNumbering &VN;
|
|
TargetData *TD;
|
|
LLVMContext *Context;
|
|
|
|
class ScopedRange {
|
|
typedef std::vector<std::pair<DomTreeDFS::Node *, ConstantRange> >
|
|
RangeListType;
|
|
RangeListType RangeList;
|
|
|
|
static bool swo(const std::pair<DomTreeDFS::Node *, ConstantRange> &LHS,
|
|
const std::pair<DomTreeDFS::Node *, ConstantRange> &RHS) {
|
|
return *LHS.first < *RHS.first;
|
|
}
|
|
|
|
public:
|
|
#ifndef NDEBUG
|
|
virtual ~ScopedRange() {}
|
|
virtual void dump() const {
|
|
dump(errs());
|
|
}
|
|
|
|
void dump(raw_ostream &os) const {
|
|
os << "{";
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I) {
|
|
os << &I->second << " (" << I->first->getDFSNumIn() << "), ";
|
|
}
|
|
os << "}";
|
|
}
|
|
#endif
|
|
|
|
typedef RangeListType::iterator iterator;
|
|
typedef RangeListType::const_iterator const_iterator;
|
|
|
|
iterator begin() { return RangeList.begin(); }
|
|
iterator end() { return RangeList.end(); }
|
|
const_iterator begin() const { return RangeList.begin(); }
|
|
const_iterator end() const { return RangeList.end(); }
|
|
|
|
iterator find(DomTreeDFS::Node *Subtree) {
|
|
iterator E = end();
|
|
iterator I = std::lower_bound(begin(), E,
|
|
std::make_pair(Subtree, empty), swo);
|
|
|
|
while (I != E && !I->first->dominates(Subtree)) ++I;
|
|
return I;
|
|
}
|
|
|
|
const_iterator find(DomTreeDFS::Node *Subtree) const {
|
|
const_iterator E = end();
|
|
const_iterator I = std::lower_bound(begin(), E,
|
|
std::make_pair(Subtree, empty), swo);
|
|
|
|
while (I != E && !I->first->dominates(Subtree)) ++I;
|
|
return I;
|
|
}
|
|
|
|
void update(const ConstantRange &CR, DomTreeDFS::Node *Subtree) {
|
|
assert(!CR.isEmptySet() && "Empty ConstantRange.");
|
|
assert(!CR.isSingleElement() && "Refusing to store single element.");
|
|
|
|
iterator E = end();
|
|
iterator I =
|
|
std::lower_bound(begin(), E, std::make_pair(Subtree, empty), swo);
|
|
|
|
if (I != end() && I->first == Subtree) {
|
|
ConstantRange CR2 = I->second.intersectWith(CR);
|
|
assert(!CR2.isEmptySet() && !CR2.isSingleElement() &&
|
|
"Invalid union of ranges.");
|
|
I->second = CR2;
|
|
} else
|
|
RangeList.insert(I, std::make_pair(Subtree, CR));
|
|
}
|
|
};
|
|
|
|
std::vector<ScopedRange> Ranges;
|
|
|
|
void update(unsigned n, const ConstantRange &CR, DomTreeDFS::Node *Subtree){
|
|
if (CR.isFullSet()) return;
|
|
if (Ranges.size() < n) Ranges.resize(n);
|
|
Ranges[n-1].update(CR, Subtree);
|
|
}
|
|
|
|
/// create - Creates a ConstantRange that matches the given LatticeVal
|
|
/// relation with a given integer.
|
|
ConstantRange create(LatticeVal LV, const ConstantRange &CR) {
|
|
assert(!CR.isEmptySet() && "Can't deal with empty set.");
|
|
|
|
if (LV == NE)
|
|
return ConstantRange::makeICmpRegion(ICmpInst::ICMP_NE, CR);
|
|
|
|
unsigned LV_s = LV & (SGT_BIT|SLT_BIT);
|
|
unsigned LV_u = LV & (UGT_BIT|ULT_BIT);
|
|
bool hasEQ = LV & EQ_BIT;
|
|
|
|
ConstantRange Range(CR.getBitWidth());
|
|
|
|
if (LV_s == SGT_BIT) {
|
|
Range = Range.intersectWith(ConstantRange::makeICmpRegion(
|
|
hasEQ ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_SGT, CR));
|
|
} else if (LV_s == SLT_BIT) {
|
|
Range = Range.intersectWith(ConstantRange::makeICmpRegion(
|
|
hasEQ ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_SLT, CR));
|
|
}
|
|
|
|
if (LV_u == UGT_BIT) {
|
|
Range = Range.intersectWith(ConstantRange::makeICmpRegion(
|
|
hasEQ ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_UGT, CR));
|
|
} else if (LV_u == ULT_BIT) {
|
|
Range = Range.intersectWith(ConstantRange::makeICmpRegion(
|
|
hasEQ ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT, CR));
|
|
}
|
|
|
|
return Range;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
bool isCanonical(Value *V, DomTreeDFS::Node *Subtree) {
|
|
return V == VN.canonicalize(V, Subtree);
|
|
}
|
|
#endif
|
|
|
|
public:
|
|
|
|
ValueRanges(ValueNumbering &VN, TargetData *TD, LLVMContext *C) :
|
|
VN(VN), TD(TD), Context(C) {}
|
|
|
|
#ifndef NDEBUG
|
|
virtual ~ValueRanges() {}
|
|
|
|
virtual void dump() const {
|
|
dump(errs());
|
|
}
|
|
|
|
void dump(raw_ostream &os) const {
|
|
for (unsigned i = 0, e = Ranges.size(); i != e; ++i) {
|
|
os << (i+1) << " = ";
|
|
Ranges[i].dump(os);
|
|
os << "\n";
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/// range - looks up the ConstantRange associated with a value number.
|
|
ConstantRange range(unsigned n, DomTreeDFS::Node *Subtree) {
|
|
assert(VN.value(n)); // performs range checks
|
|
|
|
if (n <= Ranges.size()) {
|
|
ScopedRange::iterator I = Ranges[n-1].find(Subtree);
|
|
if (I != Ranges[n-1].end()) return I->second;
|
|
}
|
|
|
|
Value *V = VN.value(n);
|
|
ConstantRange CR = range(V);
|
|
return CR;
|
|
}
|
|
|
|
/// range - determine a range from a Value without performing any lookups.
|
|
ConstantRange range(Value *V) const {
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(V))
|
|
return ConstantRange(C->getValue());
|
|
else if (isa<ConstantPointerNull>(V))
|
|
return ConstantRange(APInt::getNullValue(typeToWidth(V->getType())));
|
|
else
|
|
return ConstantRange(typeToWidth(V->getType()));
|
|
}
|
|
|
|
// typeToWidth - returns the number of bits necessary to store a value of
|
|
// this type, or zero if unknown.
|
|
uint32_t typeToWidth(const Type *Ty) const {
|
|
if (TD)
|
|
return TD->getTypeSizeInBits(Ty);
|
|
else
|
|
return Ty->getPrimitiveSizeInBits();
|
|
}
|
|
|
|
static bool isRelatedBy(const ConstantRange &CR1, const ConstantRange &CR2,
|
|
LatticeVal LV) {
|
|
switch (LV) {
|
|
default: assert(!"Impossible lattice value!");
|
|
case NE:
|
|
return CR1.intersectWith(CR2).isEmptySet();
|
|
case ULT:
|
|
return CR1.getUnsignedMax().ult(CR2.getUnsignedMin());
|
|
case ULE:
|
|
return CR1.getUnsignedMax().ule(CR2.getUnsignedMin());
|
|
case UGT:
|
|
return CR1.getUnsignedMin().ugt(CR2.getUnsignedMax());
|
|
case UGE:
|
|
return CR1.getUnsignedMin().uge(CR2.getUnsignedMax());
|
|
case SLT:
|
|
return CR1.getSignedMax().slt(CR2.getSignedMin());
|
|
case SLE:
|
|
return CR1.getSignedMax().sle(CR2.getSignedMin());
|
|
case SGT:
|
|
return CR1.getSignedMin().sgt(CR2.getSignedMax());
|
|
case SGE:
|
|
return CR1.getSignedMin().sge(CR2.getSignedMax());
|
|
case LT:
|
|
return CR1.getUnsignedMax().ult(CR2.getUnsignedMin()) &&
|
|
CR1.getSignedMax().slt(CR2.getUnsignedMin());
|
|
case LE:
|
|
return CR1.getUnsignedMax().ule(CR2.getUnsignedMin()) &&
|
|
CR1.getSignedMax().sle(CR2.getUnsignedMin());
|
|
case GT:
|
|
return CR1.getUnsignedMin().ugt(CR2.getUnsignedMax()) &&
|
|
CR1.getSignedMin().sgt(CR2.getSignedMax());
|
|
case GE:
|
|
return CR1.getUnsignedMin().uge(CR2.getUnsignedMax()) &&
|
|
CR1.getSignedMin().sge(CR2.getSignedMax());
|
|
case SLTUGT:
|
|
return CR1.getSignedMax().slt(CR2.getSignedMin()) &&
|
|
CR1.getUnsignedMin().ugt(CR2.getUnsignedMax());
|
|
case SLEUGE:
|
|
return CR1.getSignedMax().sle(CR2.getSignedMin()) &&
|
|
CR1.getUnsignedMin().uge(CR2.getUnsignedMax());
|
|
case SGTULT:
|
|
return CR1.getSignedMin().sgt(CR2.getSignedMax()) &&
|
|
CR1.getUnsignedMax().ult(CR2.getUnsignedMin());
|
|
case SGEULE:
|
|
return CR1.getSignedMin().sge(CR2.getSignedMax()) &&
|
|
CR1.getUnsignedMax().ule(CR2.getUnsignedMin());
|
|
}
|
|
}
|
|
|
|
bool isRelatedBy(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree,
|
|
LatticeVal LV) {
|
|
ConstantRange CR1 = range(n1, Subtree);
|
|
ConstantRange CR2 = range(n2, Subtree);
|
|
|
|
// True iff all values in CR1 are LV to all values in CR2.
|
|
return isRelatedBy(CR1, CR2, LV);
|
|
}
|
|
|
|
void addToWorklist(Value *V, Constant *C, ICmpInst::Predicate Pred,
|
|
VRPSolver *VRP);
|
|
void markBlock(VRPSolver *VRP);
|
|
|
|
void mergeInto(Value **I, unsigned n, unsigned New,
|
|
DomTreeDFS::Node *Subtree, VRPSolver *VRP) {
|
|
ConstantRange CR_New = range(New, Subtree);
|
|
ConstantRange Merged = CR_New;
|
|
|
|
for (; n != 0; ++I, --n) {
|
|
unsigned i = VN.valueNumber(*I, Subtree);
|
|
ConstantRange CR_Kill = i ? range(i, Subtree) : range(*I);
|
|
if (CR_Kill.isFullSet()) continue;
|
|
Merged = Merged.intersectWith(CR_Kill);
|
|
}
|
|
|
|
if (Merged.isFullSet() || Merged == CR_New) return;
|
|
|
|
applyRange(New, Merged, Subtree, VRP);
|
|
}
|
|
|
|
void applyRange(unsigned n, const ConstantRange &CR,
|
|
DomTreeDFS::Node *Subtree, VRPSolver *VRP) {
|
|
ConstantRange Merged = CR.intersectWith(range(n, Subtree));
|
|
if (Merged.isEmptySet()) {
|
|
markBlock(VRP);
|
|
return;
|
|
}
|
|
|
|
if (const APInt *I = Merged.getSingleElement()) {
|
|
Value *V = VN.value(n); // XXX: redesign worklist.
|
|
const Type *Ty = V->getType();
|
|
if (Ty->isInteger()) {
|
|
addToWorklist(V, ConstantInt::get(*Context, *I),
|
|
ICmpInst::ICMP_EQ, VRP);
|
|
return;
|
|
} else if (const PointerType *PTy = dyn_cast<PointerType>(Ty)) {
|
|
assert(*I == 0 && "Pointer is null but not zero?");
|
|
addToWorklist(V, ConstantPointerNull::get(PTy),
|
|
ICmpInst::ICMP_EQ, VRP);
|
|
return;
|
|
}
|
|
}
|
|
|
|
update(n, Merged, Subtree);
|
|
}
|
|
|
|
void addNotEquals(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree,
|
|
VRPSolver *VRP) {
|
|
ConstantRange CR1 = range(n1, Subtree);
|
|
ConstantRange CR2 = range(n2, Subtree);
|
|
|
|
uint32_t W = CR1.getBitWidth();
|
|
|
|
if (const APInt *I = CR1.getSingleElement()) {
|
|
if (CR2.isFullSet()) {
|
|
ConstantRange NewCR2(CR1.getUpper(), CR1.getLower());
|
|
applyRange(n2, NewCR2, Subtree, VRP);
|
|
} else if (*I == CR2.getLower()) {
|
|
APInt NewLower(CR2.getLower() + 1),
|
|
NewUpper(CR2.getUpper());
|
|
if (NewLower == NewUpper)
|
|
NewLower = NewUpper = APInt::getMinValue(W);
|
|
|
|
ConstantRange NewCR2(NewLower, NewUpper);
|
|
applyRange(n2, NewCR2, Subtree, VRP);
|
|
} else if (*I == CR2.getUpper() - 1) {
|
|
APInt NewLower(CR2.getLower()),
|
|
NewUpper(CR2.getUpper() - 1);
|
|
if (NewLower == NewUpper)
|
|
NewLower = NewUpper = APInt::getMinValue(W);
|
|
|
|
ConstantRange NewCR2(NewLower, NewUpper);
|
|
applyRange(n2, NewCR2, Subtree, VRP);
|
|
}
|
|
}
|
|
|
|
if (const APInt *I = CR2.getSingleElement()) {
|
|
if (CR1.isFullSet()) {
|
|
ConstantRange NewCR1(CR2.getUpper(), CR2.getLower());
|
|
applyRange(n1, NewCR1, Subtree, VRP);
|
|
} else if (*I == CR1.getLower()) {
|
|
APInt NewLower(CR1.getLower() + 1),
|
|
NewUpper(CR1.getUpper());
|
|
if (NewLower == NewUpper)
|
|
NewLower = NewUpper = APInt::getMinValue(W);
|
|
|
|
ConstantRange NewCR1(NewLower, NewUpper);
|
|
applyRange(n1, NewCR1, Subtree, VRP);
|
|
} else if (*I == CR1.getUpper() - 1) {
|
|
APInt NewLower(CR1.getLower()),
|
|
NewUpper(CR1.getUpper() - 1);
|
|
if (NewLower == NewUpper)
|
|
NewLower = NewUpper = APInt::getMinValue(W);
|
|
|
|
ConstantRange NewCR1(NewLower, NewUpper);
|
|
applyRange(n1, NewCR1, Subtree, VRP);
|
|
}
|
|
}
|
|
}
|
|
|
|
void addInequality(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree,
|
|
LatticeVal LV, VRPSolver *VRP) {
|
|
assert(!isRelatedBy(n1, n2, Subtree, LV) && "Asked to do useless work.");
|
|
|
|
if (LV == NE) {
|
|
addNotEquals(n1, n2, Subtree, VRP);
|
|
return;
|
|
}
|
|
|
|
ConstantRange CR1 = range(n1, Subtree);
|
|
ConstantRange CR2 = range(n2, Subtree);
|
|
|
|
if (!CR1.isSingleElement()) {
|
|
ConstantRange NewCR1 = CR1.intersectWith(create(LV, CR2));
|
|
if (NewCR1 != CR1)
|
|
applyRange(n1, NewCR1, Subtree, VRP);
|
|
}
|
|
|
|
if (!CR2.isSingleElement()) {
|
|
ConstantRange NewCR2 = CR2.intersectWith(
|
|
create(reversePredicate(LV), CR1));
|
|
if (NewCR2 != CR2)
|
|
applyRange(n2, NewCR2, Subtree, VRP);
|
|
}
|
|
}
|
|
};
|
|
|
|
/// UnreachableBlocks keeps tracks of blocks that are for one reason or
|
|
/// another discovered to be unreachable. This is used to cull the graph when
|
|
/// analyzing instructions, and to mark blocks with the "unreachable"
|
|
/// terminator instruction after the function has executed.
|
|
class UnreachableBlocks {
|
|
private:
|
|
std::vector<BasicBlock *> DeadBlocks;
|
|
|
|
public:
|
|
/// mark - mark a block as dead
|
|
void mark(BasicBlock *BB) {
|
|
std::vector<BasicBlock *>::iterator E = DeadBlocks.end();
|
|
std::vector<BasicBlock *>::iterator I =
|
|
std::lower_bound(DeadBlocks.begin(), E, BB);
|
|
|
|
if (I == E || *I != BB) DeadBlocks.insert(I, BB);
|
|
}
|
|
|
|
/// isDead - returns whether a block is known to be dead already
|
|
bool isDead(BasicBlock *BB) {
|
|
std::vector<BasicBlock *>::iterator E = DeadBlocks.end();
|
|
std::vector<BasicBlock *>::iterator I =
|
|
std::lower_bound(DeadBlocks.begin(), E, BB);
|
|
|
|
return I != E && *I == BB;
|
|
}
|
|
|
|
/// kill - replace the dead blocks' terminator with an UnreachableInst.
|
|
bool kill() {
|
|
bool modified = false;
|
|
for (std::vector<BasicBlock *>::iterator I = DeadBlocks.begin(),
|
|
E = DeadBlocks.end(); I != E; ++I) {
|
|
BasicBlock *BB = *I;
|
|
|
|
DEBUG(errs() << "unreachable block: " << BB->getName() << "\n");
|
|
|
|
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
|
|
SI != SE; ++SI) {
|
|
BasicBlock *Succ = *SI;
|
|
Succ->removePredecessor(BB);
|
|
}
|
|
|
|
TerminatorInst *TI = BB->getTerminator();
|
|
TI->replaceAllUsesWith(UndefValue::get(TI->getType()));
|
|
TI->eraseFromParent();
|
|
new UnreachableInst(BB->getContext(), BB);
|
|
++NumBlocks;
|
|
modified = true;
|
|
}
|
|
DeadBlocks.clear();
|
|
return modified;
|
|
}
|
|
};
|
|
|
|
/// VRPSolver keeps track of how changes to one variable affect other
|
|
/// variables, and forwards changes along to the InequalityGraph. It
|
|
/// also maintains the correct choice for "canonical" in the IG.
|
|
/// @brief VRPSolver calculates inferences from a new relationship.
|
|
class VRPSolver {
|
|
private:
|
|
friend class ValueRanges;
|
|
|
|
struct Operation {
|
|
Value *LHS, *RHS;
|
|
ICmpInst::Predicate Op;
|
|
|
|
BasicBlock *ContextBB; // XXX use a DomTreeDFS::Node instead
|
|
Instruction *ContextInst;
|
|
};
|
|
std::deque<Operation> WorkList;
|
|
|
|
ValueNumbering &VN;
|
|
InequalityGraph &IG;
|
|
UnreachableBlocks &UB;
|
|
ValueRanges &VR;
|
|
DomTreeDFS *DTDFS;
|
|
DomTreeDFS::Node *Top;
|
|
BasicBlock *TopBB;
|
|
Instruction *TopInst;
|
|
bool &modified;
|
|
LLVMContext *Context;
|
|
|
|
typedef InequalityGraph::Node Node;
|
|
|
|
// below - true if the Instruction is dominated by the current context
|
|
// block or instruction
|
|
bool below(Instruction *I) {
|
|
BasicBlock *BB = I->getParent();
|
|
if (TopInst && TopInst->getParent() == BB) {
|
|
if (isa<TerminatorInst>(TopInst)) return false;
|
|
if (isa<TerminatorInst>(I)) return true;
|
|
if ( isa<PHINode>(TopInst) && !isa<PHINode>(I)) return true;
|
|
if (!isa<PHINode>(TopInst) && isa<PHINode>(I)) return false;
|
|
|
|
for (BasicBlock::const_iterator Iter = BB->begin(), E = BB->end();
|
|
Iter != E; ++Iter) {
|
|
if (&*Iter == TopInst) return true;
|
|
else if (&*Iter == I) return false;
|
|
}
|
|
assert(!"Instructions not found in parent BasicBlock?");
|
|
} else {
|
|
DomTreeDFS::Node *Node = DTDFS->getNodeForBlock(BB);
|
|
if (!Node) return false;
|
|
return Top->dominates(Node);
|
|
}
|
|
return false; // Not reached
|
|
}
|
|
|
|
// aboveOrBelow - true if the Instruction either dominates or is dominated
|
|
// by the current context block or instruction
|
|
bool aboveOrBelow(Instruction *I) {
|
|
BasicBlock *BB = I->getParent();
|
|
DomTreeDFS::Node *Node = DTDFS->getNodeForBlock(BB);
|
|
if (!Node) return false;
|
|
|
|
return Top == Node || Top->dominates(Node) || Node->dominates(Top);
|
|
}
|
|
|
|
bool makeEqual(Value *V1, Value *V2) {
|
|
DEBUG(errs() << "makeEqual(" << *V1 << ", " << *V2 << ")\n");
|
|
DEBUG(errs() << "context is ");
|
|
DEBUG(if (TopInst)
|
|
errs() << "I: " << *TopInst << "\n";
|
|
else
|
|
errs() << "BB: " << TopBB->getName()
|
|
<< "(" << Top->getDFSNumIn() << ")\n");
|
|
|
|
assert(V1->getType() == V2->getType() &&
|
|
"Can't make two values with different types equal.");
|
|
|
|
if (V1 == V2) return true;
|
|
|
|
if (isa<Constant>(V1) && isa<Constant>(V2))
|
|
return false;
|
|
|
|
unsigned n1 = VN.valueNumber(V1, Top), n2 = VN.valueNumber(V2, Top);
|
|
|
|
if (n1 && n2) {
|
|
if (n1 == n2) return true;
|
|
if (IG.isRelatedBy(n1, n2, Top, NE)) return false;
|
|
}
|
|
|
|
if (n1) assert(V1 == VN.value(n1) && "Value isn't canonical.");
|
|
if (n2) assert(V2 == VN.value(n2) && "Value isn't canonical.");
|
|
|
|
assert(!VN.compare(V2, V1) && "Please order parameters to makeEqual.");
|
|
|
|
assert(!isa<Constant>(V2) && "Tried to remove a constant.");
|
|
|
|
SetVector<unsigned> Remove;
|
|
if (n2) Remove.insert(n2);
|
|
|
|
if (n1 && n2) {
|
|
// Suppose we're being told that %x == %y, and %x <= %z and %y >= %z.
|
|
// We can't just merge %x and %y because the relationship with %z would
|
|
// be EQ and that's invalid. What we're doing is looking for any nodes
|
|
// %z such that %x <= %z and %y >= %z, and vice versa.
|
|
|
|
Node::iterator end = IG.node(n2)->end();
|
|
|
|
// Find the intersection between N1 and N2 which is dominated by
|
|
// Top. If we find %x where N1 <= %x <= N2 (or >=) then add %x to
|
|
// Remove.
|
|
for (Node::iterator I = IG.node(n1)->begin(), E = IG.node(n1)->end();
|
|
I != E; ++I) {
|
|
if (!(I->LV & EQ_BIT) || !Top->DominatedBy(I->Subtree)) continue;
|
|
|
|
unsigned ILV_s = I->LV & (SLT_BIT|SGT_BIT);
|
|
unsigned ILV_u = I->LV & (ULT_BIT|UGT_BIT);
|
|
Node::iterator NI = IG.node(n2)->find(I->To, Top);
|
|
if (NI != end) {
|
|
LatticeVal NILV = reversePredicate(NI->LV);
|
|
unsigned NILV_s = NILV & (SLT_BIT|SGT_BIT);
|
|
unsigned NILV_u = NILV & (ULT_BIT|UGT_BIT);
|
|
|
|
if ((ILV_s != (SLT_BIT|SGT_BIT) && ILV_s == NILV_s) ||
|
|
(ILV_u != (ULT_BIT|UGT_BIT) && ILV_u == NILV_u))
|
|
Remove.insert(I->To);
|
|
}
|
|
}
|
|
|
|
// See if one of the nodes about to be removed is actually a better
|
|
// canonical choice than n1.
|
|
unsigned orig_n1 = n1;
|
|
SetVector<unsigned>::iterator DontRemove = Remove.end();
|
|
for (SetVector<unsigned>::iterator I = Remove.begin()+1 /* skip n2 */,
|
|
E = Remove.end(); I != E; ++I) {
|
|
unsigned n = *I;
|
|
Value *V = VN.value(n);
|
|
if (VN.compare(V, V1)) {
|
|
V1 = V;
|
|
n1 = n;
|
|
DontRemove = I;
|
|
}
|
|
}
|
|
if (DontRemove != Remove.end()) {
|
|
unsigned n = *DontRemove;
|
|
Remove.remove(n);
|
|
Remove.insert(orig_n1);
|
|
}
|
|
}
|
|
|
|
// We'd like to allow makeEqual on two values to perform a simple
|
|
// substitution without creating nodes in the IG whenever possible.
|
|
//
|
|
// The first iteration through this loop operates on V2 before going
|
|
// through the Remove list and operating on those too. If all of the
|
|
// iterations performed simple replacements then we exit early.
|
|
bool mergeIGNode = false;
|
|
unsigned i = 0;
|
|
for (Value *R = V2; i == 0 || i < Remove.size(); ++i) {
|
|
if (i) R = VN.value(Remove[i]); // skip n2.
|
|
|
|
// Try to replace the whole instruction. If we can, we're done.
|
|
Instruction *I2 = dyn_cast<Instruction>(R);
|
|
if (I2 && below(I2)) {
|
|
std::vector<Instruction *> ToNotify;
|
|
for (Value::use_iterator UI = I2->use_begin(), UE = I2->use_end();
|
|
UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
Instruction *I = cast<Instruction>(TheUse.getUser());
|
|
ToNotify.push_back(I);
|
|
}
|
|
|
|
DEBUG(errs() << "Simply removing " << *I2
|
|
<< ", replacing with " << *V1 << "\n");
|
|
I2->replaceAllUsesWith(V1);
|
|
// leave it dead; it'll get erased later.
|
|
++NumInstruction;
|
|
modified = true;
|
|
|
|
for (std::vector<Instruction *>::iterator II = ToNotify.begin(),
|
|
IE = ToNotify.end(); II != IE; ++II) {
|
|
opsToDef(*II);
|
|
}
|
|
|
|
continue;
|
|
}
|
|
|
|
// Otherwise, replace all dominated uses.
|
|
for (Value::use_iterator UI = R->use_begin(), UE = R->use_end();
|
|
UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) {
|
|
if (below(I)) {
|
|
TheUse.set(V1);
|
|
modified = true;
|
|
++NumVarsReplaced;
|
|
opsToDef(I);
|
|
}
|
|
}
|
|
}
|
|
|
|
// If that killed the instruction, stop here.
|
|
if (I2 && isInstructionTriviallyDead(I2)) {
|
|
DEBUG(errs() << "Killed all uses of " << *I2
|
|
<< ", replacing with " << *V1 << "\n");
|
|
continue;
|
|
}
|
|
|
|
// If we make it to here, then we will need to create a node for N1.
|
|
// Otherwise, we can skip out early!
|
|
mergeIGNode = true;
|
|
}
|
|
|
|
if (!isa<Constant>(V1)) {
|
|
if (Remove.empty()) {
|
|
VR.mergeInto(&V2, 1, VN.getOrInsertVN(V1, Top), Top, this);
|
|
} else {
|
|
std::vector<Value*> RemoveVals;
|
|
RemoveVals.reserve(Remove.size());
|
|
|
|
for (SetVector<unsigned>::iterator I = Remove.begin(),
|
|
E = Remove.end(); I != E; ++I) {
|
|
Value *V = VN.value(*I);
|
|
if (!V->use_empty())
|
|
RemoveVals.push_back(V);
|
|
}
|
|
VR.mergeInto(&RemoveVals[0], RemoveVals.size(),
|
|
VN.getOrInsertVN(V1, Top), Top, this);
|
|
}
|
|
}
|
|
|
|
if (mergeIGNode) {
|
|
// Create N1.
|
|
if (!n1) n1 = VN.getOrInsertVN(V1, Top);
|
|
IG.node(n1); // Ensure that IG.Nodes won't get resized
|
|
|
|
// Migrate relationships from removed nodes to N1.
|
|
for (SetVector<unsigned>::iterator I = Remove.begin(), E = Remove.end();
|
|
I != E; ++I) {
|
|
unsigned n = *I;
|
|
for (Node::iterator NI = IG.node(n)->begin(), NE = IG.node(n)->end();
|
|
NI != NE; ++NI) {
|
|
if (NI->Subtree->DominatedBy(Top)) {
|
|
if (NI->To == n1) {
|
|
assert((NI->LV & EQ_BIT) && "Node inequal to itself.");
|
|
continue;
|
|
}
|
|
if (Remove.count(NI->To))
|
|
continue;
|
|
|
|
IG.node(NI->To)->update(n1, reversePredicate(NI->LV), Top);
|
|
IG.node(n1)->update(NI->To, NI->LV, Top);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Point V2 (and all items in Remove) to N1.
|
|
if (!n2)
|
|
VN.addEquality(n1, V2, Top);
|
|
else {
|
|
for (SetVector<unsigned>::iterator I = Remove.begin(),
|
|
E = Remove.end(); I != E; ++I) {
|
|
VN.addEquality(n1, VN.value(*I), Top);
|
|
}
|
|
}
|
|
|
|
// If !Remove.empty() then V2 = Remove[0]->getValue().
|
|
// Even when Remove is empty, we still want to process V2.
|
|
i = 0;
|
|
for (Value *R = V2; i == 0 || i < Remove.size(); ++i) {
|
|
if (i) R = VN.value(Remove[i]); // skip n2.
|
|
|
|
if (Instruction *I2 = dyn_cast<Instruction>(R)) {
|
|
if (aboveOrBelow(I2))
|
|
defToOps(I2);
|
|
}
|
|
for (Value::use_iterator UI = V2->use_begin(), UE = V2->use_end();
|
|
UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) {
|
|
if (aboveOrBelow(I))
|
|
opsToDef(I);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// re-opsToDef all dominated users of V1.
|
|
if (Instruction *I = dyn_cast<Instruction>(V1)) {
|
|
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
|
|
UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
Value *V = TheUse.getUser();
|
|
if (!V->use_empty()) {
|
|
Instruction *Inst = cast<Instruction>(V);
|
|
if (aboveOrBelow(Inst))
|
|
opsToDef(Inst);
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// cmpInstToLattice - converts an CmpInst::Predicate to lattice value
|
|
/// Requires that the lattice value be valid; does not accept ICMP_EQ.
|
|
static LatticeVal cmpInstToLattice(ICmpInst::Predicate Pred) {
|
|
switch (Pred) {
|
|
case ICmpInst::ICMP_EQ:
|
|
assert(!"No matching lattice value.");
|
|
return static_cast<LatticeVal>(EQ_BIT);
|
|
default:
|
|
assert(!"Invalid 'icmp' predicate.");
|
|
case ICmpInst::ICMP_NE:
|
|
return NE;
|
|
case ICmpInst::ICMP_UGT:
|
|
return UGT;
|
|
case ICmpInst::ICMP_UGE:
|
|
return UGE;
|
|
case ICmpInst::ICMP_ULT:
|
|
return ULT;
|
|
case ICmpInst::ICMP_ULE:
|
|
return ULE;
|
|
case ICmpInst::ICMP_SGT:
|
|
return SGT;
|
|
case ICmpInst::ICMP_SGE:
|
|
return SGE;
|
|
case ICmpInst::ICMP_SLT:
|
|
return SLT;
|
|
case ICmpInst::ICMP_SLE:
|
|
return SLE;
|
|
}
|
|
}
|
|
|
|
public:
|
|
VRPSolver(ValueNumbering &VN, InequalityGraph &IG, UnreachableBlocks &UB,
|
|
ValueRanges &VR, DomTreeDFS *DTDFS, bool &modified,
|
|
BasicBlock *TopBB)
|
|
: VN(VN),
|
|
IG(IG),
|
|
UB(UB),
|
|
VR(VR),
|
|
DTDFS(DTDFS),
|
|
Top(DTDFS->getNodeForBlock(TopBB)),
|
|
TopBB(TopBB),
|
|
TopInst(NULL),
|
|
modified(modified),
|
|
Context(&TopBB->getContext())
|
|
{
|
|
assert(Top && "VRPSolver created for unreachable basic block.");
|
|
}
|
|
|
|
VRPSolver(ValueNumbering &VN, InequalityGraph &IG, UnreachableBlocks &UB,
|
|
ValueRanges &VR, DomTreeDFS *DTDFS, bool &modified,
|
|
Instruction *TopInst)
|
|
: VN(VN),
|
|
IG(IG),
|
|
UB(UB),
|
|
VR(VR),
|
|
DTDFS(DTDFS),
|
|
Top(DTDFS->getNodeForBlock(TopInst->getParent())),
|
|
TopBB(TopInst->getParent()),
|
|
TopInst(TopInst),
|
|
modified(modified),
|
|
Context(&TopInst->getContext())
|
|
{
|
|
assert(Top && "VRPSolver created for unreachable basic block.");
|
|
assert(Top->getBlock() == TopInst->getParent() && "Context mismatch.");
|
|
}
|
|
|
|
bool isRelatedBy(Value *V1, Value *V2, ICmpInst::Predicate Pred) const {
|
|
if (Constant *C1 = dyn_cast<Constant>(V1))
|
|
if (Constant *C2 = dyn_cast<Constant>(V2))
|
|
return ConstantExpr::getCompare(Pred, C1, C2) ==
|
|
ConstantInt::getTrue(*Context);
|
|
|
|
unsigned n1 = VN.valueNumber(V1, Top);
|
|
unsigned n2 = VN.valueNumber(V2, Top);
|
|
|
|
if (n1 && n2) {
|
|
if (n1 == n2) return Pred == ICmpInst::ICMP_EQ ||
|
|
Pred == ICmpInst::ICMP_ULE ||
|
|
Pred == ICmpInst::ICMP_UGE ||
|
|
Pred == ICmpInst::ICMP_SLE ||
|
|
Pred == ICmpInst::ICMP_SGE;
|
|
if (Pred == ICmpInst::ICMP_EQ) return false;
|
|
if (IG.isRelatedBy(n1, n2, Top, cmpInstToLattice(Pred))) return true;
|
|
if (VR.isRelatedBy(n1, n2, Top, cmpInstToLattice(Pred))) return true;
|
|
}
|
|
|
|
if ((n1 && !n2 && isa<Constant>(V2)) ||
|
|
(n2 && !n1 && isa<Constant>(V1))) {
|
|
ConstantRange CR1 = n1 ? VR.range(n1, Top) : VR.range(V1);
|
|
ConstantRange CR2 = n2 ? VR.range(n2, Top) : VR.range(V2);
|
|
|
|
if (Pred == ICmpInst::ICMP_EQ)
|
|
return CR1.isSingleElement() &&
|
|
CR1.getSingleElement() == CR2.getSingleElement();
|
|
|
|
return VR.isRelatedBy(CR1, CR2, cmpInstToLattice(Pred));
|
|
}
|
|
if (Pred == ICmpInst::ICMP_EQ) return V1 == V2;
|
|
return false;
|
|
}
|
|
|
|
/// add - adds a new property to the work queue
|
|
void add(Value *V1, Value *V2, ICmpInst::Predicate Pred,
|
|
Instruction *I = NULL) {
|
|
DEBUG(errs() << "adding " << *V1 << " " << Pred << " " << *V2);
|
|
if (I)
|
|
DEBUG(errs() << " context: " << *I);
|
|
else
|
|
DEBUG(errs() << " default context (" << Top->getDFSNumIn() << ")");
|
|
DEBUG(errs() << "\n");
|
|
|
|
assert(V1->getType() == V2->getType() &&
|
|
"Can't relate two values with different types.");
|
|
|
|
WorkList.push_back(Operation());
|
|
Operation &O = WorkList.back();
|
|
O.LHS = V1, O.RHS = V2, O.Op = Pred, O.ContextInst = I;
|
|
O.ContextBB = I ? I->getParent() : TopBB;
|
|
}
|
|
|
|
/// defToOps - Given an instruction definition that we've learned something
|
|
/// new about, find any new relationships between its operands.
|
|
void defToOps(Instruction *I) {
|
|
Instruction *NewContext = below(I) ? I : TopInst;
|
|
Value *Canonical = VN.canonicalize(I, Top);
|
|
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
const Type *Ty = BO->getType();
|
|
assert(!Ty->isFPOrFPVector() && "Float in work queue!");
|
|
|
|
Value *Op0 = VN.canonicalize(BO->getOperand(0), Top);
|
|
Value *Op1 = VN.canonicalize(BO->getOperand(1), Top);
|
|
|
|
// TODO: "and i32 -1, %x" EQ %y then %x EQ %y.
|
|
|
|
switch (BO->getOpcode()) {
|
|
case Instruction::And: {
|
|
// "and i32 %a, %b" EQ -1 then %a EQ -1 and %b EQ -1
|
|
ConstantInt *CI = cast<ConstantInt>(Constant::getAllOnesValue(Ty));
|
|
if (Canonical == CI) {
|
|
add(CI, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
add(CI, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
} break;
|
|
case Instruction::Or: {
|
|
// "or i32 %a, %b" EQ 0 then %a EQ 0 and %b EQ 0
|
|
Constant *Zero = Constant::getNullValue(Ty);
|
|
if (Canonical == Zero) {
|
|
add(Zero, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
add(Zero, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
} break;
|
|
case Instruction::Xor: {
|
|
// "xor i32 %c, %a" EQ %b then %a EQ %c ^ %b
|
|
// "xor i32 %c, %a" EQ %c then %a EQ 0
|
|
// "xor i32 %c, %a" NE %c then %a NE 0
|
|
// Repeat the above, with order of operands reversed.
|
|
Value *LHS = Op0;
|
|
Value *RHS = Op1;
|
|
if (!isa<Constant>(LHS)) std::swap(LHS, RHS);
|
|
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(Canonical)) {
|
|
if (ConstantInt *Arg = dyn_cast<ConstantInt>(LHS)) {
|
|
add(RHS,
|
|
ConstantInt::get(*Context, CI->getValue() ^ Arg->getValue()),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
}
|
|
if (Canonical == LHS) {
|
|
if (isa<ConstantInt>(Canonical))
|
|
add(RHS, Constant::getNullValue(Ty), ICmpInst::ICMP_EQ,
|
|
NewContext);
|
|
} else if (isRelatedBy(LHS, Canonical, ICmpInst::ICMP_NE)) {
|
|
add(RHS, Constant::getNullValue(Ty), ICmpInst::ICMP_NE,
|
|
NewContext);
|
|
}
|
|
} break;
|
|
default:
|
|
break;
|
|
}
|
|
} else if (ICmpInst *IC = dyn_cast<ICmpInst>(I)) {
|
|
// "icmp ult i32 %a, %y" EQ true then %a u< y
|
|
// etc.
|
|
|
|
if (Canonical == ConstantInt::getTrue(*Context)) {
|
|
add(IC->getOperand(0), IC->getOperand(1), IC->getPredicate(),
|
|
NewContext);
|
|
} else if (Canonical == ConstantInt::getFalse(*Context)) {
|
|
add(IC->getOperand(0), IC->getOperand(1),
|
|
ICmpInst::getInversePredicate(IC->getPredicate()), NewContext);
|
|
}
|
|
} else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
|
|
if (I->getType()->isFPOrFPVector()) return;
|
|
|
|
// Given: "%a = select i1 %x, i32 %b, i32 %c"
|
|
// %a EQ %b and %b NE %c then %x EQ true
|
|
// %a EQ %c and %b NE %c then %x EQ false
|
|
|
|
Value *True = SI->getTrueValue();
|
|
Value *False = SI->getFalseValue();
|
|
if (isRelatedBy(True, False, ICmpInst::ICMP_NE)) {
|
|
if (Canonical == VN.canonicalize(True, Top) ||
|
|
isRelatedBy(Canonical, False, ICmpInst::ICMP_NE))
|
|
add(SI->getCondition(), ConstantInt::getTrue(*Context),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
else if (Canonical == VN.canonicalize(False, Top) ||
|
|
isRelatedBy(Canonical, True, ICmpInst::ICMP_NE))
|
|
add(SI->getCondition(), ConstantInt::getFalse(*Context),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
|
|
for (GetElementPtrInst::op_iterator OI = GEPI->idx_begin(),
|
|
OE = GEPI->idx_end(); OI != OE; ++OI) {
|
|
ConstantInt *Op = dyn_cast<ConstantInt>(VN.canonicalize(*OI, Top));
|
|
if (!Op || !Op->isZero()) return;
|
|
}
|
|
// TODO: The GEPI indices are all zero. Copy from definition to operand,
|
|
// jumping the type plane as needed.
|
|
if (isRelatedBy(GEPI, Constant::getNullValue(GEPI->getType()),
|
|
ICmpInst::ICMP_NE)) {
|
|
Value *Ptr = GEPI->getPointerOperand();
|
|
add(Ptr, Constant::getNullValue(Ptr->getType()), ICmpInst::ICMP_NE,
|
|
NewContext);
|
|
}
|
|
} else if (CastInst *CI = dyn_cast<CastInst>(I)) {
|
|
const Type *SrcTy = CI->getSrcTy();
|
|
|
|
unsigned ci = VN.getOrInsertVN(CI, Top);
|
|
uint32_t W = VR.typeToWidth(SrcTy);
|
|
if (!W) return;
|
|
ConstantRange CR = VR.range(ci, Top);
|
|
|
|
if (CR.isFullSet()) return;
|
|
|
|
switch (CI->getOpcode()) {
|
|
default: break;
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
VR.applyRange(VN.getOrInsertVN(CI->getOperand(0), Top),
|
|
CR.truncate(W), Top, this);
|
|
break;
|
|
case Instruction::BitCast:
|
|
VR.applyRange(VN.getOrInsertVN(CI->getOperand(0), Top),
|
|
CR, Top, this);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// opsToDef - A new relationship was discovered involving one of this
|
|
/// instruction's operands. Find any new relationship involving the
|
|
/// definition, or another operand.
|
|
void opsToDef(Instruction *I) {
|
|
Instruction *NewContext = below(I) ? I : TopInst;
|
|
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
|
|
Value *Op0 = VN.canonicalize(BO->getOperand(0), Top);
|
|
Value *Op1 = VN.canonicalize(BO->getOperand(1), Top);
|
|
|
|
if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0))
|
|
if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
|
|
add(BO, ConstantExpr::get(BO->getOpcode(), CI0, CI1),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
|
|
// "%y = and i1 true, %x" then %x EQ %y
|
|
// "%y = or i1 false, %x" then %x EQ %y
|
|
// "%x = add i32 %y, 0" then %x EQ %y
|
|
// "%x = mul i32 %y, 0" then %x EQ 0
|
|
|
|
Instruction::BinaryOps Opcode = BO->getOpcode();
|
|
const Type *Ty = BO->getType();
|
|
assert(!Ty->isFPOrFPVector() && "Float in work queue!");
|
|
|
|
Constant *Zero = Constant::getNullValue(Ty);
|
|
Constant *One = ConstantInt::get(Ty, 1);
|
|
ConstantInt *AllOnes = cast<ConstantInt>(Constant::getAllOnesValue(Ty));
|
|
|
|
switch (Opcode) {
|
|
default: break;
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::Shl:
|
|
if (Op1 == Zero) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
break;
|
|
case Instruction::Sub:
|
|
if (Op1 == Zero) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
|
|
unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
|
|
ConstantRange CR = VR.range(n_ci0, Top);
|
|
if (!CR.isFullSet()) {
|
|
CR.subtract(CI0->getValue());
|
|
unsigned n_bo = VN.getOrInsertVN(BO, Top);
|
|
VR.applyRange(n_bo, CR, Top, this);
|
|
return;
|
|
}
|
|
}
|
|
if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
|
|
unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
|
|
ConstantRange CR = VR.range(n_ci1, Top);
|
|
if (!CR.isFullSet()) {
|
|
CR.subtract(CI1->getValue());
|
|
unsigned n_bo = VN.getOrInsertVN(BO, Top);
|
|
VR.applyRange(n_bo, CR, Top, this);
|
|
return;
|
|
}
|
|
}
|
|
break;
|
|
case Instruction::Or:
|
|
if (Op0 == AllOnes || Op1 == AllOnes) {
|
|
add(BO, AllOnes, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
if (Op0 == Zero) {
|
|
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
} else if (Op1 == Zero) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
break;
|
|
case Instruction::Add:
|
|
if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
|
|
unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
|
|
ConstantRange CR = VR.range(n_ci0, Top);
|
|
if (!CR.isFullSet()) {
|
|
CR.subtract(-CI0->getValue());
|
|
unsigned n_bo = VN.getOrInsertVN(BO, Top);
|
|
VR.applyRange(n_bo, CR, Top, this);
|
|
return;
|
|
}
|
|
}
|
|
if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
|
|
unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
|
|
ConstantRange CR = VR.range(n_ci1, Top);
|
|
if (!CR.isFullSet()) {
|
|
CR.subtract(-CI1->getValue());
|
|
unsigned n_bo = VN.getOrInsertVN(BO, Top);
|
|
VR.applyRange(n_bo, CR, Top, this);
|
|
return;
|
|
}
|
|
}
|
|
// fall-through
|
|
case Instruction::Xor:
|
|
if (Op0 == Zero) {
|
|
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
} else if (Op1 == Zero) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
break;
|
|
case Instruction::And:
|
|
if (Op0 == AllOnes) {
|
|
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
} else if (Op1 == AllOnes) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
if (Op0 == Zero || Op1 == Zero) {
|
|
add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
break;
|
|
case Instruction::Mul:
|
|
if (Op0 == Zero || Op1 == Zero) {
|
|
add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
if (Op0 == One) {
|
|
add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
} else if (Op1 == One) {
|
|
add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
|
|
// "%x = add i32 %y, %z" and %x EQ %y then %z EQ 0
|
|
// "%x = add i32 %y, %z" and %x EQ %z then %y EQ 0
|
|
// "%x = shl i32 %y, %z" and %x EQ %y and %y NE 0 then %z EQ 0
|
|
// "%x = udiv i32 %y, %z" and %x EQ %y and %y NE 0 then %z EQ 1
|
|
|
|
Value *Known = Op0, *Unknown = Op1,
|
|
*TheBO = VN.canonicalize(BO, Top);
|
|
if (Known != TheBO) std::swap(Known, Unknown);
|
|
if (Known == TheBO) {
|
|
switch (Opcode) {
|
|
default: break;
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::Shl:
|
|
if (!isRelatedBy(Known, Zero, ICmpInst::ICMP_NE)) break;
|
|
// otherwise, fall-through.
|
|
case Instruction::Sub:
|
|
if (Unknown == Op0) break;
|
|
// otherwise, fall-through.
|
|
case Instruction::Xor:
|
|
case Instruction::Add:
|
|
add(Unknown, Zero, ICmpInst::ICMP_EQ, NewContext);
|
|
break;
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
if (Unknown == Op1) break;
|
|
if (isRelatedBy(Known, Zero, ICmpInst::ICMP_NE))
|
|
add(Unknown, One, ICmpInst::ICMP_EQ, NewContext);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// TODO: "%a = add i32 %b, 1" and %b > %z then %a >= %z.
|
|
|
|
} else if (ICmpInst *IC = dyn_cast<ICmpInst>(I)) {
|
|
// "%a = icmp ult i32 %b, %c" and %b u< %c then %a EQ true
|
|
// "%a = icmp ult i32 %b, %c" and %b u>= %c then %a EQ false
|
|
// etc.
|
|
|
|
Value *Op0 = VN.canonicalize(IC->getOperand(0), Top);
|
|
Value *Op1 = VN.canonicalize(IC->getOperand(1), Top);
|
|
|
|
ICmpInst::Predicate Pred = IC->getPredicate();
|
|
if (isRelatedBy(Op0, Op1, Pred))
|
|
add(IC, ConstantInt::getTrue(*Context), ICmpInst::ICMP_EQ, NewContext);
|
|
else if (isRelatedBy(Op0, Op1, ICmpInst::getInversePredicate(Pred)))
|
|
add(IC, ConstantInt::getFalse(*Context),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
|
|
} else if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
|
|
if (I->getType()->isFPOrFPVector()) return;
|
|
|
|
// Given: "%a = select i1 %x, i32 %b, i32 %c"
|
|
// %x EQ true then %a EQ %b
|
|
// %x EQ false then %a EQ %c
|
|
// %b EQ %c then %a EQ %b
|
|
|
|
Value *Canonical = VN.canonicalize(SI->getCondition(), Top);
|
|
if (Canonical == ConstantInt::getTrue(*Context)) {
|
|
add(SI, SI->getTrueValue(), ICmpInst::ICMP_EQ, NewContext);
|
|
} else if (Canonical == ConstantInt::getFalse(*Context)) {
|
|
add(SI, SI->getFalseValue(), ICmpInst::ICMP_EQ, NewContext);
|
|
} else if (VN.canonicalize(SI->getTrueValue(), Top) ==
|
|
VN.canonicalize(SI->getFalseValue(), Top)) {
|
|
add(SI, SI->getTrueValue(), ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
} else if (CastInst *CI = dyn_cast<CastInst>(I)) {
|
|
const Type *DestTy = CI->getDestTy();
|
|
if (DestTy->isFPOrFPVector()) return;
|
|
|
|
Value *Op = VN.canonicalize(CI->getOperand(0), Top);
|
|
Instruction::CastOps Opcode = CI->getOpcode();
|
|
|
|
if (Constant *C = dyn_cast<Constant>(Op)) {
|
|
add(CI, ConstantExpr::getCast(Opcode, C, DestTy),
|
|
ICmpInst::ICMP_EQ, NewContext);
|
|
}
|
|
|
|
uint32_t W = VR.typeToWidth(DestTy);
|
|
unsigned ci = VN.getOrInsertVN(CI, Top);
|
|
ConstantRange CR = VR.range(VN.getOrInsertVN(Op, Top), Top);
|
|
|
|
if (!CR.isFullSet()) {
|
|
switch (Opcode) {
|
|
default: break;
|
|
case Instruction::ZExt:
|
|
VR.applyRange(ci, CR.zeroExtend(W), Top, this);
|
|
break;
|
|
case Instruction::SExt:
|
|
VR.applyRange(ci, CR.signExtend(W), Top, this);
|
|
break;
|
|
case Instruction::Trunc: {
|
|
ConstantRange Result = CR.truncate(W);
|
|
if (!Result.isFullSet())
|
|
VR.applyRange(ci, Result, Top, this);
|
|
} break;
|
|
case Instruction::BitCast:
|
|
VR.applyRange(ci, CR, Top, this);
|
|
break;
|
|
// TODO: other casts?
|
|
}
|
|
}
|
|
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
|
|
for (GetElementPtrInst::op_iterator OI = GEPI->idx_begin(),
|
|
OE = GEPI->idx_end(); OI != OE; ++OI) {
|
|
ConstantInt *Op = dyn_cast<ConstantInt>(VN.canonicalize(*OI, Top));
|
|
if (!Op || !Op->isZero()) return;
|
|
}
|
|
// TODO: The GEPI indices are all zero. Copy from operand to definition,
|
|
// jumping the type plane as needed.
|
|
Value *Ptr = GEPI->getPointerOperand();
|
|
if (isRelatedBy(Ptr, Constant::getNullValue(Ptr->getType()),
|
|
ICmpInst::ICMP_NE)) {
|
|
add(GEPI, Constant::getNullValue(GEPI->getType()), ICmpInst::ICMP_NE,
|
|
NewContext);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// solve - process the work queue
|
|
void solve() {
|
|
//DEBUG(errs() << "WorkList entry, size: " << WorkList.size() << "\n");
|
|
while (!WorkList.empty()) {
|
|
//DEBUG(errs() << "WorkList size: " << WorkList.size() << "\n");
|
|
|
|
Operation &O = WorkList.front();
|
|
TopInst = O.ContextInst;
|
|
TopBB = O.ContextBB;
|
|
Top = DTDFS->getNodeForBlock(TopBB); // XXX move this into Context
|
|
|
|
O.LHS = VN.canonicalize(O.LHS, Top);
|
|
O.RHS = VN.canonicalize(O.RHS, Top);
|
|
|
|
assert(O.LHS == VN.canonicalize(O.LHS, Top) && "Canonicalize isn't.");
|
|
assert(O.RHS == VN.canonicalize(O.RHS, Top) && "Canonicalize isn't.");
|
|
|
|
DEBUG(errs() << "solving " << *O.LHS << " " << O.Op << " " << *O.RHS;
|
|
if (O.ContextInst)
|
|
errs() << " context inst: " << *O.ContextInst;
|
|
else
|
|
errs() << " context block: " << O.ContextBB->getName();
|
|
errs() << "\n";
|
|
|
|
VN.dump();
|
|
IG.dump();
|
|
VR.dump(););
|
|
|
|
// If they're both Constant, skip it. Check for contradiction and mark
|
|
// the BB as unreachable if so.
|
|
if (Constant *CI_L = dyn_cast<Constant>(O.LHS)) {
|
|
if (Constant *CI_R = dyn_cast<Constant>(O.RHS)) {
|
|
if (ConstantExpr::getCompare(O.Op, CI_L, CI_R) ==
|
|
ConstantInt::getFalse(*Context))
|
|
UB.mark(TopBB);
|
|
|
|
WorkList.pop_front();
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (VN.compare(O.LHS, O.RHS)) {
|
|
std::swap(O.LHS, O.RHS);
|
|
O.Op = ICmpInst::getSwappedPredicate(O.Op);
|
|
}
|
|
|
|
if (O.Op == ICmpInst::ICMP_EQ) {
|
|
if (!makeEqual(O.RHS, O.LHS))
|
|
UB.mark(TopBB);
|
|
} else {
|
|
LatticeVal LV = cmpInstToLattice(O.Op);
|
|
|
|
if ((LV & EQ_BIT) &&
|
|
isRelatedBy(O.LHS, O.RHS, ICmpInst::getSwappedPredicate(O.Op))) {
|
|
if (!makeEqual(O.RHS, O.LHS))
|
|
UB.mark(TopBB);
|
|
} else {
|
|
if (isRelatedBy(O.LHS, O.RHS, ICmpInst::getInversePredicate(O.Op))){
|
|
UB.mark(TopBB);
|
|
WorkList.pop_front();
|
|
continue;
|
|
}
|
|
|
|
unsigned n1 = VN.getOrInsertVN(O.LHS, Top);
|
|
unsigned n2 = VN.getOrInsertVN(O.RHS, Top);
|
|
|
|
if (n1 == n2) {
|
|
if (O.Op != ICmpInst::ICMP_UGE && O.Op != ICmpInst::ICMP_ULE &&
|
|
O.Op != ICmpInst::ICMP_SGE && O.Op != ICmpInst::ICMP_SLE)
|
|
UB.mark(TopBB);
|
|
|
|
WorkList.pop_front();
|
|
continue;
|
|
}
|
|
|
|
if (VR.isRelatedBy(n1, n2, Top, LV) ||
|
|
IG.isRelatedBy(n1, n2, Top, LV)) {
|
|
WorkList.pop_front();
|
|
continue;
|
|
}
|
|
|
|
VR.addInequality(n1, n2, Top, LV, this);
|
|
if ((!isa<ConstantInt>(O.RHS) && !isa<ConstantInt>(O.LHS)) ||
|
|
LV == NE)
|
|
IG.addInequality(n1, n2, Top, LV);
|
|
|
|
if (Instruction *I1 = dyn_cast<Instruction>(O.LHS)) {
|
|
if (aboveOrBelow(I1))
|
|
defToOps(I1);
|
|
}
|
|
if (isa<Instruction>(O.LHS) || isa<Argument>(O.LHS)) {
|
|
for (Value::use_iterator UI = O.LHS->use_begin(),
|
|
UE = O.LHS->use_end(); UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
Instruction *I = cast<Instruction>(TheUse.getUser());
|
|
if (aboveOrBelow(I))
|
|
opsToDef(I);
|
|
}
|
|
}
|
|
if (Instruction *I2 = dyn_cast<Instruction>(O.RHS)) {
|
|
if (aboveOrBelow(I2))
|
|
defToOps(I2);
|
|
}
|
|
if (isa<Instruction>(O.RHS) || isa<Argument>(O.RHS)) {
|
|
for (Value::use_iterator UI = O.RHS->use_begin(),
|
|
UE = O.RHS->use_end(); UI != UE;) {
|
|
Use &TheUse = UI.getUse();
|
|
++UI;
|
|
Instruction *I = cast<Instruction>(TheUse.getUser());
|
|
if (aboveOrBelow(I))
|
|
opsToDef(I);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
WorkList.pop_front();
|
|
}
|
|
}
|
|
};
|
|
|
|
void ValueRanges::addToWorklist(Value *V, Constant *C,
|
|
ICmpInst::Predicate Pred, VRPSolver *VRP) {
|
|
VRP->add(V, C, Pred, VRP->TopInst);
|
|
}
|
|
|
|
void ValueRanges::markBlock(VRPSolver *VRP) {
|
|
VRP->UB.mark(VRP->TopBB);
|
|
}
|
|
|
|
/// PredicateSimplifier - This class is a simplifier that replaces
|
|
/// one equivalent variable with another. It also tracks what
|
|
/// can't be equal and will solve setcc instructions when possible.
|
|
/// @brief Root of the predicate simplifier optimization.
|
|
class PredicateSimplifier : public FunctionPass {
|
|
DomTreeDFS *DTDFS;
|
|
bool modified;
|
|
ValueNumbering *VN;
|
|
InequalityGraph *IG;
|
|
UnreachableBlocks UB;
|
|
ValueRanges *VR;
|
|
|
|
std::vector<DomTreeDFS::Node *> WorkList;
|
|
|
|
LLVMContext *Context;
|
|
public:
|
|
static char ID; // Pass identification, replacement for typeid
|
|
PredicateSimplifier() : FunctionPass(&ID) {}
|
|
|
|
bool runOnFunction(Function &F);
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.addRequiredID(BreakCriticalEdgesID);
|
|
AU.addRequired<DominatorTree>();
|
|
}
|
|
|
|
private:
|
|
/// Forwards - Adds new properties to VRPSolver and uses them to
|
|
/// simplify instructions. Because new properties sometimes apply to
|
|
/// a transition from one BasicBlock to another, this will use the
|
|
/// PredicateSimplifier::proceedToSuccessor(s) interface to enter the
|
|
/// basic block.
|
|
/// @brief Performs abstract execution of the program.
|
|
class Forwards : public InstVisitor<Forwards> {
|
|
friend class InstVisitor<Forwards>;
|
|
PredicateSimplifier *PS;
|
|
DomTreeDFS::Node *DTNode;
|
|
|
|
public:
|
|
ValueNumbering &VN;
|
|
InequalityGraph &IG;
|
|
UnreachableBlocks &UB;
|
|
ValueRanges &VR;
|
|
|
|
Forwards(PredicateSimplifier *PS, DomTreeDFS::Node *DTNode)
|
|
: PS(PS), DTNode(DTNode), VN(*PS->VN), IG(*PS->IG), UB(PS->UB),
|
|
VR(*PS->VR) {}
|
|
|
|
void visitTerminatorInst(TerminatorInst &TI);
|
|
void visitBranchInst(BranchInst &BI);
|
|
void visitSwitchInst(SwitchInst &SI);
|
|
|
|
void visitAllocaInst(AllocaInst &AI);
|
|
void visitLoadInst(LoadInst &LI);
|
|
void visitStoreInst(StoreInst &SI);
|
|
|
|
void visitSExtInst(SExtInst &SI);
|
|
void visitZExtInst(ZExtInst &ZI);
|
|
|
|
void visitBinaryOperator(BinaryOperator &BO);
|
|
void visitICmpInst(ICmpInst &IC);
|
|
};
|
|
|
|
// Used by terminator instructions to proceed from the current basic
|
|
// block to the next. Verifies that "current" dominates "next",
|
|
// then calls visitBasicBlock.
|
|
void proceedToSuccessors(DomTreeDFS::Node *Current) {
|
|
for (DomTreeDFS::Node::iterator I = Current->begin(),
|
|
E = Current->end(); I != E; ++I) {
|
|
WorkList.push_back(*I);
|
|
}
|
|
}
|
|
|
|
void proceedToSuccessor(DomTreeDFS::Node *Next) {
|
|
WorkList.push_back(Next);
|
|
}
|
|
|
|
// Visits each instruction in the basic block.
|
|
void visitBasicBlock(DomTreeDFS::Node *Node) {
|
|
BasicBlock *BB = Node->getBlock();
|
|
DEBUG(errs() << "Entering Basic Block: " << BB->getName()
|
|
<< " (" << Node->getDFSNumIn() << ")\n");
|
|
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
|
|
visitInstruction(I++, Node);
|
|
}
|
|
}
|
|
|
|
// Tries to simplify each Instruction and add new properties.
|
|
void visitInstruction(Instruction *I, DomTreeDFS::Node *DT) {
|
|
DEBUG(errs() << "Considering instruction " << *I << "\n");
|
|
DEBUG(VN->dump());
|
|
DEBUG(IG->dump());
|
|
DEBUG(VR->dump());
|
|
|
|
// Sometimes instructions are killed in earlier analysis.
|
|
if (isInstructionTriviallyDead(I)) {
|
|
++NumSimple;
|
|
modified = true;
|
|
if (unsigned n = VN->valueNumber(I, DTDFS->getRootNode()))
|
|
if (VN->value(n) == I) IG->remove(n);
|
|
VN->remove(I);
|
|
I->eraseFromParent();
|
|
return;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
// Try to replace the whole instruction.
|
|
Value *V = VN->canonicalize(I, DT);
|
|
assert(V == I && "Late instruction canonicalization.");
|
|
if (V != I) {
|
|
modified = true;
|
|
++NumInstruction;
|
|
DEBUG(errs() << "Removing " << *I << ", replacing with " << *V << "\n");
|
|
if (unsigned n = VN->valueNumber(I, DTDFS->getRootNode()))
|
|
if (VN->value(n) == I) IG->remove(n);
|
|
VN->remove(I);
|
|
I->replaceAllUsesWith(V);
|
|
I->eraseFromParent();
|
|
return;
|
|
}
|
|
|
|
// Try to substitute operands.
|
|
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
|
|
Value *Oper = I->getOperand(i);
|
|
Value *V = VN->canonicalize(Oper, DT);
|
|
assert(V == Oper && "Late operand canonicalization.");
|
|
if (V != Oper) {
|
|
modified = true;
|
|
++NumVarsReplaced;
|
|
DEBUG(errs() << "Resolving " << *I);
|
|
I->setOperand(i, V);
|
|
DEBUG(errs() << " into " << *I);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
std::string name = I->getParent()->getName();
|
|
DEBUG(errs() << "push (%" << name << ")\n");
|
|
Forwards visit(this, DT);
|
|
visit.visit(*I);
|
|
DEBUG(errs() << "pop (%" << name << ")\n");
|
|
}
|
|
};
|
|
|
|
bool PredicateSimplifier::runOnFunction(Function &F) {
|
|
DominatorTree *DT = &getAnalysis<DominatorTree>();
|
|
DTDFS = new DomTreeDFS(DT);
|
|
TargetData *TD = getAnalysisIfAvailable<TargetData>();
|
|
|
|
// FIXME: PredicateSimplifier should still be able to do basic
|
|
// optimizations without TargetData. But for now, just exit if
|
|
// it's not available.
|
|
if (!TD) return false;
|
|
|
|
Context = &F.getContext();
|
|
|
|
DEBUG(errs() << "Entering Function: " << F.getName() << "\n");
|
|
|
|
modified = false;
|
|
DomTreeDFS::Node *Root = DTDFS->getRootNode();
|
|
VN = new ValueNumbering(DTDFS);
|
|
IG = new InequalityGraph(*VN, Root);
|
|
VR = new ValueRanges(*VN, TD, Context);
|
|
WorkList.push_back(Root);
|
|
|
|
do {
|
|
DomTreeDFS::Node *DTNode = WorkList.back();
|
|
WorkList.pop_back();
|
|
if (!UB.isDead(DTNode->getBlock())) visitBasicBlock(DTNode);
|
|
} while (!WorkList.empty());
|
|
|
|
delete DTDFS;
|
|
delete VR;
|
|
delete IG;
|
|
delete VN;
|
|
|
|
modified |= UB.kill();
|
|
|
|
return modified;
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitTerminatorInst(TerminatorInst &TI) {
|
|
PS->proceedToSuccessors(DTNode);
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitBranchInst(BranchInst &BI) {
|
|
if (BI.isUnconditional()) {
|
|
PS->proceedToSuccessors(DTNode);
|
|
return;
|
|
}
|
|
|
|
Value *Condition = BI.getCondition();
|
|
BasicBlock *TrueDest = BI.getSuccessor(0);
|
|
BasicBlock *FalseDest = BI.getSuccessor(1);
|
|
|
|
if (isa<Constant>(Condition) || TrueDest == FalseDest) {
|
|
PS->proceedToSuccessors(DTNode);
|
|
return;
|
|
}
|
|
|
|
LLVMContext *Context = &BI.getContext();
|
|
|
|
for (DomTreeDFS::Node::iterator I = DTNode->begin(), E = DTNode->end();
|
|
I != E; ++I) {
|
|
BasicBlock *Dest = (*I)->getBlock();
|
|
DEBUG(errs() << "Branch thinking about %" << Dest->getName()
|
|
<< "(" << PS->DTDFS->getNodeForBlock(Dest)->getDFSNumIn() << ")\n");
|
|
|
|
if (Dest == TrueDest) {
|
|
DEBUG(errs() << "(" << DTNode->getBlock()->getName()
|
|
<< ") true set:\n");
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest);
|
|
VRP.add(ConstantInt::getTrue(*Context), Condition, ICmpInst::ICMP_EQ);
|
|
VRP.solve();
|
|
DEBUG(VN.dump());
|
|
DEBUG(IG.dump());
|
|
DEBUG(VR.dump());
|
|
} else if (Dest == FalseDest) {
|
|
DEBUG(errs() << "(" << DTNode->getBlock()->getName()
|
|
<< ") false set:\n");
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest);
|
|
VRP.add(ConstantInt::getFalse(*Context), Condition, ICmpInst::ICMP_EQ);
|
|
VRP.solve();
|
|
DEBUG(VN.dump());
|
|
DEBUG(IG.dump());
|
|
DEBUG(VR.dump());
|
|
}
|
|
|
|
PS->proceedToSuccessor(*I);
|
|
}
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitSwitchInst(SwitchInst &SI) {
|
|
Value *Condition = SI.getCondition();
|
|
|
|
// Set the EQProperty in each of the cases BBs, and the NEProperties
|
|
// in the default BB.
|
|
|
|
for (DomTreeDFS::Node::iterator I = DTNode->begin(), E = DTNode->end();
|
|
I != E; ++I) {
|
|
BasicBlock *BB = (*I)->getBlock();
|
|
DEBUG(errs() << "Switch thinking about BB %" << BB->getName()
|
|
<< "(" << PS->DTDFS->getNodeForBlock(BB)->getDFSNumIn() << ")\n");
|
|
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, BB);
|
|
if (BB == SI.getDefaultDest()) {
|
|
for (unsigned i = 1, e = SI.getNumCases(); i < e; ++i)
|
|
if (SI.getSuccessor(i) != BB)
|
|
VRP.add(Condition, SI.getCaseValue(i), ICmpInst::ICMP_NE);
|
|
VRP.solve();
|
|
} else if (ConstantInt *CI = SI.findCaseDest(BB)) {
|
|
VRP.add(Condition, CI, ICmpInst::ICMP_EQ);
|
|
VRP.solve();
|
|
}
|
|
PS->proceedToSuccessor(*I);
|
|
}
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitAllocaInst(AllocaInst &AI) {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &AI);
|
|
VRP.add(Constant::getNullValue(AI.getType()),
|
|
&AI, ICmpInst::ICMP_NE);
|
|
VRP.solve();
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitLoadInst(LoadInst &LI) {
|
|
Value *Ptr = LI.getPointerOperand();
|
|
// avoid "load i8* null" -> null NE null.
|
|
if (isa<Constant>(Ptr)) return;
|
|
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &LI);
|
|
VRP.add(Constant::getNullValue(Ptr->getType()),
|
|
Ptr, ICmpInst::ICMP_NE);
|
|
VRP.solve();
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitStoreInst(StoreInst &SI) {
|
|
Value *Ptr = SI.getPointerOperand();
|
|
if (isa<Constant>(Ptr)) return;
|
|
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &SI);
|
|
VRP.add(Constant::getNullValue(Ptr->getType()),
|
|
Ptr, ICmpInst::ICMP_NE);
|
|
VRP.solve();
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitSExtInst(SExtInst &SI) {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &SI);
|
|
LLVMContext &Context = SI.getContext();
|
|
uint32_t SrcBitWidth = cast<IntegerType>(SI.getSrcTy())->getBitWidth();
|
|
uint32_t DstBitWidth = cast<IntegerType>(SI.getDestTy())->getBitWidth();
|
|
APInt Min(APInt::getHighBitsSet(DstBitWidth, DstBitWidth-SrcBitWidth+1));
|
|
APInt Max(APInt::getLowBitsSet(DstBitWidth, SrcBitWidth-1));
|
|
VRP.add(ConstantInt::get(Context, Min), &SI, ICmpInst::ICMP_SLE);
|
|
VRP.add(ConstantInt::get(Context, Max), &SI, ICmpInst::ICMP_SGE);
|
|
VRP.solve();
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitZExtInst(ZExtInst &ZI) {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &ZI);
|
|
LLVMContext &Context = ZI.getContext();
|
|
uint32_t SrcBitWidth = cast<IntegerType>(ZI.getSrcTy())->getBitWidth();
|
|
uint32_t DstBitWidth = cast<IntegerType>(ZI.getDestTy())->getBitWidth();
|
|
APInt Max(APInt::getLowBitsSet(DstBitWidth, SrcBitWidth));
|
|
VRP.add(ConstantInt::get(Context, Max), &ZI, ICmpInst::ICMP_UGE);
|
|
VRP.solve();
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitBinaryOperator(BinaryOperator &BO) {
|
|
Instruction::BinaryOps ops = BO.getOpcode();
|
|
|
|
switch (ops) {
|
|
default: break;
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv: {
|
|
Value *Divisor = BO.getOperand(1);
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(Constant::getNullValue(Divisor->getType()),
|
|
Divisor, ICmpInst::ICMP_NE);
|
|
VRP.solve();
|
|
break;
|
|
}
|
|
}
|
|
|
|
switch (ops) {
|
|
default: break;
|
|
case Instruction::Shl: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_UGE);
|
|
VRP.solve();
|
|
} break;
|
|
case Instruction::AShr: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_SLE);
|
|
VRP.solve();
|
|
} break;
|
|
case Instruction::LShr:
|
|
case Instruction::UDiv: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_ULE);
|
|
VRP.solve();
|
|
} break;
|
|
case Instruction::URem: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_ULE);
|
|
VRP.solve();
|
|
} break;
|
|
case Instruction::And: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_ULE);
|
|
VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_ULE);
|
|
VRP.solve();
|
|
} break;
|
|
case Instruction::Or: {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO);
|
|
VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_UGE);
|
|
VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_UGE);
|
|
VRP.solve();
|
|
} break;
|
|
}
|
|
}
|
|
|
|
void PredicateSimplifier::Forwards::visitICmpInst(ICmpInst &IC) {
|
|
// If possible, squeeze the ICmp predicate into something simpler.
|
|
// Eg., if x = [0, 4) and we're being asked icmp uge %x, 3 then change
|
|
// the predicate to eq.
|
|
|
|
// XXX: once we do full PHI handling, modifying the instruction in the
|
|
// Forwards visitor will cause missed optimizations.
|
|
|
|
ICmpInst::Predicate Pred = IC.getPredicate();
|
|
|
|
switch (Pred) {
|
|
default: break;
|
|
case ICmpInst::ICMP_ULE: Pred = ICmpInst::ICMP_ULT; break;
|
|
case ICmpInst::ICMP_UGE: Pred = ICmpInst::ICMP_UGT; break;
|
|
case ICmpInst::ICMP_SLE: Pred = ICmpInst::ICMP_SLT; break;
|
|
case ICmpInst::ICMP_SGE: Pred = ICmpInst::ICMP_SGT; break;
|
|
}
|
|
if (Pred != IC.getPredicate()) {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &IC);
|
|
if (VRP.isRelatedBy(IC.getOperand(1), IC.getOperand(0),
|
|
ICmpInst::ICMP_NE)) {
|
|
++NumSnuggle;
|
|
PS->modified = true;
|
|
IC.setPredicate(Pred);
|
|
}
|
|
}
|
|
|
|
Pred = IC.getPredicate();
|
|
|
|
LLVMContext &Context = IC.getContext();
|
|
|
|
if (ConstantInt *Op1 = dyn_cast<ConstantInt>(IC.getOperand(1))) {
|
|
ConstantInt *NextVal = 0;
|
|
switch (Pred) {
|
|
default: break;
|
|
case ICmpInst::ICMP_SLT:
|
|
case ICmpInst::ICMP_ULT:
|
|
if (Op1->getValue() != 0)
|
|
NextVal = ConstantInt::get(Context, Op1->getValue()-1);
|
|
break;
|
|
case ICmpInst::ICMP_SGT:
|
|
case ICmpInst::ICMP_UGT:
|
|
if (!Op1->getValue().isAllOnesValue())
|
|
NextVal = ConstantInt::get(Context, Op1->getValue()+1);
|
|
break;
|
|
}
|
|
|
|
if (NextVal) {
|
|
VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &IC);
|
|
if (VRP.isRelatedBy(IC.getOperand(0), NextVal,
|
|
ICmpInst::getInversePredicate(Pred))) {
|
|
ICmpInst *NewIC = new ICmpInst(&IC, ICmpInst::ICMP_EQ,
|
|
IC.getOperand(0), NextVal, "");
|
|
NewIC->takeName(&IC);
|
|
IC.replaceAllUsesWith(NewIC);
|
|
|
|
// XXX: prove this isn't necessary
|
|
if (unsigned n = VN.valueNumber(&IC, PS->DTDFS->getRootNode()))
|
|
if (VN.value(n) == &IC) IG.remove(n);
|
|
VN.remove(&IC);
|
|
|
|
IC.eraseFromParent();
|
|
++NumSnuggle;
|
|
PS->modified = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
char PredicateSimplifier::ID = 0;
|
|
static RegisterPass<PredicateSimplifier>
|
|
X("predsimplify", "Predicate Simplifier");
|
|
|
|
FunctionPass *llvm::createPredicateSimplifierPass() {
|
|
return new PredicateSimplifier();
|
|
}
|