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[CodeMoverUtils] Improve IsControlFlowEquivalent.
Summary: Currently IsControlFlowEquivalent determine if two blocks are control flow equivalent by checking if A dominates B and B post dominates A. There exists blocks that are control flow equivalent even if they don't satisfy the A dominates B and B post dominates A condition. For example, if (cond) A if (cond) B In the PR, we determine if two blocks are control flow equivalent by also checking if the two sets of conditions A and B depends on are equivalent. Reviewer: jdoerfert, Meinersbur, dmgreen, etiotto, bmahjour, fhahn, hfinkel, kbarton Reviewed By: fhahn Subscribers: hiraditya, llvm-commits Tag: LLVM Differential Revision: https://reviews.llvm.org/D71578
This commit is contained in:
Whitney Tsang
parent
f83f5a6e3c
commit
03f2c49843
@ -23,33 +23,30 @@ class Instruction;
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class PostDominatorTree;
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/// Return true if \p I0 and \p I1 are control flow equivalent.
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/// Two instructions are control flow equivalent if when one executes,
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/// the other is guaranteed to execute. This is determined using dominators
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/// and post-dominators: if A dominates B and B post-dominates A then A and B
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/// are control-flow equivalent.
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/// Two instructions are control flow equivalent if their basic blocks are
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/// control flow equivalent.
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bool isControlFlowEquivalent(const Instruction &I0, const Instruction &I1,
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const DominatorTree &DT,
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const PostDominatorTree &PDT);
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/// Return true if \p BB0 and \p BB1 are control flow equivalent.
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/// Two basic blocks are control flow equivalent if when one executes, the other
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/// is guaranteed to execute. This is determined using dominators and
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/// post-dominators: if A dominates B and B post-dominates A then A and B are
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/// control-flow equivalent.
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/// is guaranteed to execute.
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bool isControlFlowEquivalent(const BasicBlock &BB0, const BasicBlock &BB1,
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const DominatorTree &DT,
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const PostDominatorTree &PDT);
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/// Return true if \p I can be safely moved before \p InsertPoint.
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bool isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
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const DominatorTree &DT, const PostDominatorTree &PDT,
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DominatorTree &DT, const PostDominatorTree &PDT,
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DependenceInfo &DI);
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/// Move instructions from \p FromBB bottom up to the beginning of \p ToBB
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/// when proven safe.
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void moveInstsBottomUp(BasicBlock &FromBB, BasicBlock &ToBB,
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const DominatorTree &DT, const PostDominatorTree &PDT,
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DependenceInfo &DI);
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/// Move instructions, in an order-preserving manner, from \p FromBB to the
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/// beginning of \p ToBB when proven safe.
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void moveInstructionsToTheBeginning(BasicBlock &FromBB, BasicBlock &ToBB,
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DominatorTree &DT,
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const PostDominatorTree &PDT,
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DependenceInfo &DI);
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} // end namespace llvm
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@ -1123,7 +1123,7 @@ private:
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/// Move instructions from FC0.Latch to FC1.Latch. If FC0.Latch has an unique
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/// successor, then merge FC0.Latch with its unique successor.
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void mergeLatch(const FusionCandidate &FC0, const FusionCandidate &FC1) {
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moveInstsBottomUp(*FC0.Latch, *FC1.Latch, DT, PDT, DI);
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moveInstructionsToTheBeginning(*FC0.Latch, *FC1.Latch, DT, PDT, DI);
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if (BasicBlock *Succ = FC0.Latch->getUniqueSuccessor()) {
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MergeBlockIntoPredecessor(Succ, &DTU, &LI);
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DTU.flush();
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@ -12,8 +12,10 @@
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/CodeMoverUtils.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/DependenceAnalysis.h"
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#include "llvm/Analysis/OrderedInstructions.h"
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#include "llvm/Analysis/PostDominators.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/IR/Dominators.h"
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@ -30,6 +32,189 @@ STATISTIC(NotControlFlowEquivalent,
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STATISTIC(NotMovedPHINode, "Movement of PHINodes are not supported");
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STATISTIC(NotMovedTerminator, "Movement of Terminator are not supported");
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namespace {
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/// Represent a control condition. A control condition is a condition of a
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/// terminator to decide which successors to execute. The pointer field
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/// represents the address of the condition of the terminator. The integer field
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/// is a bool, it is true when the basic block is executed when V is true. For
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/// example, `br %cond, bb0, bb1` %cond is a control condition of bb0 with the
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/// integer field equals to true, while %cond is a control condition of bb1 with
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/// the integer field equals to false.
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using ControlCondition = PointerIntPair<Value *, 1, bool>;
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#ifndef NDEBUG
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raw_ostream &operator<<(raw_ostream &OS, const ControlCondition &C) {
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OS << "[" << *C.getPointer() << ", " << (C.getInt() ? "true" : "false")
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<< "]";
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return OS;
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}
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#endif
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/// Represent a set of control conditions required to execute ToBB from FromBB.
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class ControlConditions {
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using ConditionVectorTy = SmallVector<ControlCondition, 6>;
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/// A SmallVector of control conditions.
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ConditionVectorTy Conditions;
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public:
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/// Return a ControlConditions which stores all conditions required to execute
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/// \p BB from \p Dominator. If \p MaxLookup is non-zero, it limits the
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/// number of conditions to collect. Return None if not all conditions are
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/// collected successfully, or we hit the limit.
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static Optional<const ControlConditions>
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collectControlConditions(const BasicBlock &BB, const BasicBlock &Dominator,
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const DominatorTree &DT,
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const PostDominatorTree &PDT,
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unsigned MaxLookup = 6);
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/// Return true if there exists no control conditions required to execute ToBB
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/// from FromBB.
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bool isUnconditional() const { return Conditions.empty(); }
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/// Return a constant reference of Conditions.
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const ConditionVectorTy &getControlConditions() const { return Conditions; }
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/// Add \p V as one of the ControlCondition in Condition with IsTrueCondition
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/// equals to \p True. Return true if inserted successfully.
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bool addControlCondition(ControlCondition C);
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/// Return true if for all control conditions in Conditions, there exists an
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/// equivalent control condition in \p Other.Conditions.
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bool isEquivalent(const ControlConditions &Other) const;
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/// Return true if \p C1 and \p C2 are equivalent.
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static bool isEquivalent(const ControlCondition &C1,
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const ControlCondition &C2);
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private:
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ControlConditions() = default;
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static bool isEquivalent(const Value &V1, const Value &V2);
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static bool isInverse(const Value &V1, const Value &V2);
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};
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} // namespace
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Optional<const ControlConditions> ControlConditions::collectControlConditions(
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const BasicBlock &BB, const BasicBlock &Dominator, const DominatorTree &DT,
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const PostDominatorTree &PDT, unsigned MaxLookup) {
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assert(DT.dominates(&Dominator, &BB) && "Expecting Dominator to dominate BB");
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ControlConditions Conditions;
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unsigned NumConditions = 0;
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// BB is executed unconditional from itself.
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if (&Dominator == &BB)
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return Conditions;
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const BasicBlock *CurBlock = &BB;
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// Walk up the dominator tree from the associated DT node for BB to the
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// associated DT node for Dominator.
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do {
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assert(DT.getNode(CurBlock) && "Expecting a valid DT node for CurBlock");
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BasicBlock *IDom = DT.getNode(CurBlock)->getIDom()->getBlock();
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assert(DT.dominates(&Dominator, IDom) &&
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"Expecting Dominator to dominate IDom");
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// Limitation: can only handle branch instruction currently.
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const BranchInst *BI = dyn_cast<BranchInst>(IDom->getTerminator());
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if (!BI)
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return None;
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bool Inserted = false;
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if (PDT.dominates(CurBlock, IDom)) {
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LLVM_DEBUG(dbgs() << CurBlock->getName()
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<< " is executed unconditionally from "
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<< IDom->getName() << "\n");
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} else if (PDT.dominates(CurBlock, BI->getSuccessor(0))) {
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LLVM_DEBUG(dbgs() << CurBlock->getName() << " is executed when \""
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<< *BI->getCondition() << "\" is true from "
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<< IDom->getName() << "\n");
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Inserted = Conditions.addControlCondition(
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ControlCondition(BI->getCondition(), true));
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} else if (PDT.dominates(CurBlock, BI->getSuccessor(1))) {
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LLVM_DEBUG(dbgs() << CurBlock->getName() << " is executed when \""
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<< *BI->getCondition() << "\" is false from "
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<< IDom->getName() << "\n");
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Inserted = Conditions.addControlCondition(
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ControlCondition(BI->getCondition(), false));
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} else
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return None;
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if (Inserted)
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++NumConditions;
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if (MaxLookup != 0 && NumConditions > MaxLookup)
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return None;
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CurBlock = IDom;
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} while (CurBlock != &Dominator);
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return Conditions;
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}
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bool ControlConditions::addControlCondition(ControlCondition C) {
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bool Inserted = false;
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if (none_of(Conditions, [&C](ControlCondition &Exists) {
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return ControlConditions::isEquivalent(C, Exists);
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})) {
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Conditions.push_back(C);
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Inserted = true;
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}
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LLVM_DEBUG(dbgs() << (Inserted ? "Inserted " : "Not inserted ") << C << "\n");
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return Inserted;
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}
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bool ControlConditions::isEquivalent(const ControlConditions &Other) const {
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if (Conditions.empty() && Other.Conditions.empty())
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return true;
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if (Conditions.size() != Other.Conditions.size())
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return false;
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return all_of(Conditions, [&Other](const ControlCondition &C) {
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return any_of(Other.Conditions, [&C](const ControlCondition &OtherC) {
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return ControlConditions::isEquivalent(C, OtherC);
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});
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});
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}
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bool ControlConditions::isEquivalent(const ControlCondition &C1,
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const ControlCondition &C2) {
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if (C1.getInt() == C2.getInt()) {
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if (isEquivalent(*C1.getPointer(), *C2.getPointer()))
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return true;
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} else if (isInverse(*C1.getPointer(), *C2.getPointer()))
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return true;
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return false;
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}
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// FIXME: Use SCEV and reuse GVN/CSE logic to check for equivalence between
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// Values.
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// Currently, isEquivalent rely on other passes to ensure equivalent conditions
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// have the same value, e.g. GVN.
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bool ControlConditions::isEquivalent(const Value &V1, const Value &V2) {
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return &V1 == &V2;
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}
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bool ControlConditions::isInverse(const Value &V1, const Value &V2) {
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if (const CmpInst *Cmp1 = dyn_cast<CmpInst>(&V1))
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if (const CmpInst *Cmp2 = dyn_cast<CmpInst>(&V2)) {
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if (Cmp1->getPredicate() == Cmp2->getInversePredicate() &&
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Cmp1->getOperand(0) == Cmp2->getOperand(0) &&
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Cmp1->getOperand(1) == Cmp2->getOperand(1))
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return true;
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if (Cmp1->getPredicate() ==
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CmpInst::getSwappedPredicate(Cmp2->getInversePredicate()) &&
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Cmp1->getOperand(0) == Cmp2->getOperand(1) &&
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Cmp1->getOperand(1) == Cmp2->getOperand(0))
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return true;
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}
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return false;
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}
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bool llvm::isControlFlowEquivalent(const Instruction &I0, const Instruction &I1,
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const DominatorTree &DT,
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const PostDominatorTree &PDT) {
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@ -42,8 +227,30 @@ bool llvm::isControlFlowEquivalent(const BasicBlock &BB0, const BasicBlock &BB1,
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if (&BB0 == &BB1)
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return true;
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return ((DT.dominates(&BB0, &BB1) && PDT.dominates(&BB1, &BB0)) ||
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(PDT.dominates(&BB0, &BB1) && DT.dominates(&BB1, &BB0)));
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if ((DT.dominates(&BB0, &BB1) && PDT.dominates(&BB1, &BB0)) ||
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(PDT.dominates(&BB0, &BB1) && DT.dominates(&BB1, &BB0)))
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return true;
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// If the set of conditions required to execute BB0 and BB1 from their common
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// dominator are the same, then BB0 and BB1 are control flow equivalent.
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const BasicBlock *CommonDominator = DT.findNearestCommonDominator(&BB0, &BB1);
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LLVM_DEBUG(dbgs() << "The nearest common dominator of " << BB0.getName()
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<< " and " << BB1.getName() << " is "
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<< CommonDominator->getName() << "\n");
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Optional<const ControlConditions> BB0Conditions =
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ControlConditions::collectControlConditions(BB0, *CommonDominator, DT,
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PDT);
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if (BB0Conditions == None)
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return false;
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Optional<const ControlConditions> BB1Conditions =
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ControlConditions::collectControlConditions(BB1, *CommonDominator, DT,
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PDT);
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if (BB1Conditions == None)
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return false;
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return BB0Conditions->isEquivalent(*BB1Conditions);
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}
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static bool reportInvalidCandidate(const Instruction &I,
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@ -90,8 +297,7 @@ collectInstructionsInBetween(Instruction &StartInst, const Instruction &EndInst,
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}
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bool llvm::isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
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const DominatorTree &DT,
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const PostDominatorTree &PDT,
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DominatorTree &DT, const PostDominatorTree &PDT,
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DependenceInfo &DI) {
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// Cannot move itself before itself.
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if (&I == &InsertPoint)
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@ -111,9 +317,9 @@ bool llvm::isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
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if (!isControlFlowEquivalent(I, InsertPoint, DT, PDT))
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return reportInvalidCandidate(I, NotControlFlowEquivalent);
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// As I and InsertPoint are control flow equivalent, if I dominates
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// InsertPoint, then I comes before InsertPoint.
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const bool MoveForward = DT.dominates(&I, &InsertPoint);
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OrderedInstructions OI(&DT);
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DT.updateDFSNumbers();
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const bool MoveForward = OI.dfsBefore(&I, &InsertPoint);
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if (MoveForward) {
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// When I is being moved forward, we need to make sure the InsertPoint
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// dominates every users. Or else, a user may be using an undefined I.
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@ -126,7 +332,7 @@ bool llvm::isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
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// dominates the InsertPoint. Or else, an operand may be undefined for I.
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for (const Value *Op : I.operands())
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if (auto *OpInst = dyn_cast<Instruction>(Op))
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if (&InsertPoint == OpInst || !DT.dominates(OpInst, &InsertPoint))
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if (&InsertPoint == OpInst || !OI.dominates(OpInst, &InsertPoint))
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return false;
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}
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@ -174,9 +380,10 @@ bool llvm::isSafeToMoveBefore(Instruction &I, Instruction &InsertPoint,
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return true;
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}
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void llvm::moveInstsBottomUp(BasicBlock &FromBB, BasicBlock &ToBB,
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const DominatorTree &DT,
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const PostDominatorTree &PDT, DependenceInfo &DI) {
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void llvm::moveInstructionsToTheBeginning(BasicBlock &FromBB, BasicBlock &ToBB,
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DominatorTree &DT,
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const PostDominatorTree &PDT,
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DependenceInfo &DI) {
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for (auto It = ++FromBB.rbegin(); It != FromBB.rend();) {
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Instruction *MovePos = ToBB.getFirstNonPHIOrDbg();
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Instruction &I = *It;
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@ -45,7 +45,389 @@ static void run(Module &M, StringRef FuncName,
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Test(*F, DT, PDT, DI);
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}
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TEST(CodeMoverUtils, BasicTest) {
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static BasicBlock *getBasicBlockByName(Function &F, StringRef Name) {
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for (BasicBlock &BB : F)
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if (BB.getName() == Name)
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return &BB;
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llvm_unreachable("Expected to find basic block!");
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}
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static Instruction *getInstructionByName(Function &F, StringRef Name) {
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for (BasicBlock &BB : F)
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for (Instruction &I : BB)
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if (I.getName() == Name)
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return &I;
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llvm_unreachable("Expected to find instruction!");
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}
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TEST(CodeMoverUtils, IsControlFlowEquivalentSimpleTest) {
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LLVMContext C;
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// void foo(int &i, bool cond1, bool cond2) {
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// if (cond1)
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// i = 1;
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// if (cond1)
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// i = 2;
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// if (cond2)
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// i = 3;
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// }
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std::unique_ptr<Module> M =
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parseIR(C, R"(define void @foo(i32* %i, i1 %cond1, i1 %cond2) {
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entry:
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br i1 %cond1, label %if.first, label %if.first.end
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if.first:
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store i32 1, i32* %i, align 4
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br label %if.first.end
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if.first.end:
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br i1 %cond1, label %if.second, label %if.second.end
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if.second:
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store i32 2, i32* %i, align 4
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br label %if.second.end
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if.second.end:
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br i1 %cond2, label %if.third, label %if.third.end
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if.third:
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store i32 3, i32* %i, align 4
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br label %if.third.end
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if.third.end:
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ret void
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})");
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run(*M, "foo",
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[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
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DependenceInfo &DI) {
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BasicBlock *FirstIfBody = getBasicBlockByName(F, "if.first");
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EXPECT_TRUE(
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isControlFlowEquivalent(*FirstIfBody, *FirstIfBody, DT, PDT));
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BasicBlock *SecondIfBody = getBasicBlockByName(F, "if.second");
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EXPECT_TRUE(
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isControlFlowEquivalent(*FirstIfBody, *SecondIfBody, DT, PDT));
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BasicBlock *ThirdIfBody = getBasicBlockByName(F, "if.third");
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EXPECT_FALSE(
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isControlFlowEquivalent(*FirstIfBody, *ThirdIfBody, DT, PDT));
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EXPECT_FALSE(
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isControlFlowEquivalent(*SecondIfBody, *ThirdIfBody, DT, PDT));
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});
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}
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TEST(CodeMoverUtils, IsControlFlowEquivalentOppositeCondTest) {
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LLVMContext C;
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// void foo(int &i, unsigned X, unsigned Y) {
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// if (X < Y)
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// i = 1;
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// if (Y > X)
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// i = 2;
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// if (X >= Y)
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// i = 3;
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// else
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// i = 4;
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// if (X == Y)
|
||||
// i = 5;
|
||||
// if (Y == X)
|
||||
// i = 6;
|
||||
// else
|
||||
// i = 7;
|
||||
// if (X != Y)
|
||||
// i = 8;
|
||||
// else
|
||||
// i = 9;
|
||||
// }
|
||||
std::unique_ptr<Module> M =
|
||||
parseIR(C, R"(define void @foo(i32* %i, i32 %X, i32 %Y) {
|
||||
entry:
|
||||
%cmp1 = icmp ult i32 %X, %Y
|
||||
br i1 %cmp1, label %if.first, label %if.first.end
|
||||
if.first:
|
||||
store i32 1, i32* %i, align 4
|
||||
br label %if.first.end
|
||||
if.first.end:
|
||||
%cmp2 = icmp ugt i32 %Y, %X
|
||||
br i1 %cmp2, label %if.second, label %if.second.end
|
||||
if.second:
|
||||
store i32 2, i32* %i, align 4
|
||||
br label %if.second.end
|
||||
if.second.end:
|
||||
%cmp3 = icmp uge i32 %X, %Y
|
||||
br i1 %cmp3, label %if.third, label %if.third.else
|
||||
if.third:
|
||||
store i32 3, i32* %i, align 4
|
||||
br label %if.third.end
|
||||
if.third.else:
|
||||
store i32 4, i32* %i, align 4
|
||||
br label %if.third.end
|
||||
if.third.end:
|
||||
%cmp4 = icmp eq i32 %X, %Y
|
||||
br i1 %cmp4, label %if.fourth, label %if.fourth.end
|
||||
if.fourth:
|
||||
store i32 5, i32* %i, align 4
|
||||
br label %if.fourth.end
|
||||
if.fourth.end:
|
||||
%cmp5 = icmp eq i32 %Y, %X
|
||||
br i1 %cmp5, label %if.fifth, label %if.fifth.else
|
||||
if.fifth:
|
||||
store i32 6, i32* %i, align 4
|
||||
br label %if.fifth.end
|
||||
if.fifth.else:
|
||||
store i32 7, i32* %i, align 4
|
||||
br label %if.fifth.end
|
||||
if.fifth.end:
|
||||
%cmp6 = icmp ne i32 %X, %Y
|
||||
br i1 %cmp6, label %if.sixth, label %if.sixth.else
|
||||
if.sixth:
|
||||
store i32 8, i32* %i, align 4
|
||||
br label %if.sixth.end
|
||||
if.sixth.else:
|
||||
store i32 9, i32* %i, align 4
|
||||
br label %if.sixth.end
|
||||
if.sixth.end:
|
||||
ret void
|
||||
})");
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
BasicBlock *FirstIfBody = getBasicBlockByName(F, "if.first");
|
||||
BasicBlock *SecondIfBody = getBasicBlockByName(F, "if.second");
|
||||
BasicBlock *ThirdIfBody = getBasicBlockByName(F, "if.third");
|
||||
BasicBlock *ThirdElseBody = getBasicBlockByName(F, "if.third.else");
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*FirstIfBody, *ThirdElseBody, DT, PDT));
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*SecondIfBody, *ThirdElseBody, DT, PDT));
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*ThirdIfBody, *ThirdElseBody, DT, PDT));
|
||||
|
||||
BasicBlock *FourthIfBody = getBasicBlockByName(F, "if.fourth");
|
||||
BasicBlock *FifthIfBody = getBasicBlockByName(F, "if.fifth");
|
||||
BasicBlock *FifthElseBody = getBasicBlockByName(F, "if.fifth.else");
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*FifthIfBody, *FifthElseBody, DT, PDT));
|
||||
BasicBlock *SixthIfBody = getBasicBlockByName(F, "if.sixth");
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*FifthElseBody, *SixthIfBody, DT, PDT));
|
||||
BasicBlock *SixthElseBody = getBasicBlockByName(F, "if.sixth.else");
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*FourthIfBody, *SixthElseBody, DT, PDT));
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*FifthIfBody, *SixthElseBody, DT, PDT));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsControlFlowEquivalentCondNestTest) {
|
||||
LLVMContext C;
|
||||
|
||||
// void foo(int &i, bool cond1, bool cond2) {
|
||||
// if (cond1)
|
||||
// if (cond2)
|
||||
// i = 1;
|
||||
// if (cond2)
|
||||
// if (cond1)
|
||||
// i = 2;
|
||||
// }
|
||||
std::unique_ptr<Module> M =
|
||||
parseIR(C, R"(define void @foo(i32* %i, i1 %cond1, i1 %cond2) {
|
||||
entry:
|
||||
br i1 %cond1, label %if.outer.first, label %if.first.end
|
||||
if.outer.first:
|
||||
br i1 %cond2, label %if.inner.first, label %if.first.end
|
||||
if.inner.first:
|
||||
store i32 1, i32* %i, align 4
|
||||
br label %if.first.end
|
||||
if.first.end:
|
||||
br i1 %cond2, label %if.outer.second, label %if.second.end
|
||||
if.outer.second:
|
||||
br i1 %cond1, label %if.inner.second, label %if.second.end
|
||||
if.inner.second:
|
||||
store i32 2, i32* %i, align 4
|
||||
br label %if.second.end
|
||||
if.second.end:
|
||||
ret void
|
||||
})");
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
BasicBlock *FirstOuterIfBody = getBasicBlockByName(F, "if.outer.first");
|
||||
BasicBlock *FirstInnerIfBody = getBasicBlockByName(F, "if.inner.first");
|
||||
BasicBlock *SecondOuterIfBody =
|
||||
getBasicBlockByName(F, "if.outer.second");
|
||||
BasicBlock *SecondInnerIfBody =
|
||||
getBasicBlockByName(F, "if.inner.second");
|
||||
EXPECT_TRUE(isControlFlowEquivalent(*FirstInnerIfBody,
|
||||
*SecondInnerIfBody, DT, PDT));
|
||||
EXPECT_FALSE(isControlFlowEquivalent(*FirstOuterIfBody,
|
||||
*SecondOuterIfBody, DT, PDT));
|
||||
EXPECT_FALSE(isControlFlowEquivalent(*FirstOuterIfBody,
|
||||
*SecondInnerIfBody, DT, PDT));
|
||||
EXPECT_FALSE(isControlFlowEquivalent(*FirstInnerIfBody,
|
||||
*SecondOuterIfBody, DT, PDT));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsControlFlowEquivalentImbalanceTest) {
|
||||
LLVMContext C;
|
||||
|
||||
// void foo(int &i, bool cond1, bool cond2) {
|
||||
// if (cond1)
|
||||
// if (cond2)
|
||||
// if (cond3)
|
||||
// i = 1;
|
||||
// if (cond2)
|
||||
// if (cond3)
|
||||
// i = 2;
|
||||
// if (cond1)
|
||||
// if (cond1)
|
||||
// i = 3;
|
||||
// if (cond1)
|
||||
// i = 4;
|
||||
// }
|
||||
std::unique_ptr<Module> M = parseIR(
|
||||
C, R"(define void @foo(i32* %i, i1 %cond1, i1 %cond2, i1 %cond3) {
|
||||
entry:
|
||||
br i1 %cond1, label %if.outer.first, label %if.first.end
|
||||
if.outer.first:
|
||||
br i1 %cond2, label %if.middle.first, label %if.first.end
|
||||
if.middle.first:
|
||||
br i1 %cond3, label %if.inner.first, label %if.first.end
|
||||
if.inner.first:
|
||||
store i32 1, i32* %i, align 4
|
||||
br label %if.first.end
|
||||
if.first.end:
|
||||
br i1 %cond2, label %if.outer.second, label %if.second.end
|
||||
if.outer.second:
|
||||
br i1 %cond3, label %if.inner.second, label %if.second.end
|
||||
if.inner.second:
|
||||
store i32 2, i32* %i, align 4
|
||||
br label %if.second.end
|
||||
if.second.end:
|
||||
br i1 %cond1, label %if.outer.third, label %if.third.end
|
||||
if.outer.third:
|
||||
br i1 %cond1, label %if.inner.third, label %if.third.end
|
||||
if.inner.third:
|
||||
store i32 3, i32* %i, align 4
|
||||
br label %if.third.end
|
||||
if.third.end:
|
||||
br i1 %cond1, label %if.fourth, label %if.fourth.end
|
||||
if.fourth:
|
||||
store i32 4, i32* %i, align 4
|
||||
br label %if.fourth.end
|
||||
if.fourth.end:
|
||||
ret void
|
||||
})");
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
BasicBlock *FirstIfBody = getBasicBlockByName(F, "if.inner.first");
|
||||
BasicBlock *SecondIfBody = getBasicBlockByName(F, "if.inner.second");
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*FirstIfBody, *SecondIfBody, DT, PDT));
|
||||
|
||||
BasicBlock *ThirdIfBody = getBasicBlockByName(F, "if.inner.third");
|
||||
BasicBlock *FourthIfBody = getBasicBlockByName(F, "if.fourth");
|
||||
EXPECT_TRUE(
|
||||
isControlFlowEquivalent(*ThirdIfBody, *FourthIfBody, DT, PDT));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsControlFlowEquivalentPointerTest) {
|
||||
LLVMContext C;
|
||||
|
||||
// void foo(int &i, int *cond) {
|
||||
// if (*cond)
|
||||
// i = 1;
|
||||
// if (*cond)
|
||||
// i = 2;
|
||||
// *cond = 1;
|
||||
// if (*cond)
|
||||
// i = 3;
|
||||
// }
|
||||
std::unique_ptr<Module> M =
|
||||
parseIR(C, R"(define void @foo(i32* %i, i32* %cond) {
|
||||
entry:
|
||||
%0 = load i32, i32* %cond, align 4
|
||||
%tobool1 = icmp ne i32 %0, 0
|
||||
br i1 %tobool1, label %if.first, label %if.first.end
|
||||
if.first:
|
||||
store i32 1, i32* %i, align 4
|
||||
br label %if.first.end
|
||||
if.first.end:
|
||||
%1 = load i32, i32* %cond, align 4
|
||||
%tobool2 = icmp ne i32 %1, 0
|
||||
br i1 %tobool2, label %if.second, label %if.second.end
|
||||
if.second:
|
||||
store i32 2, i32* %i, align 4
|
||||
br label %if.second.end
|
||||
if.second.end:
|
||||
store i32 1, i32* %cond, align 4
|
||||
%2 = load i32, i32* %cond, align 4
|
||||
%tobool3 = icmp ne i32 %2, 0
|
||||
br i1 %tobool3, label %if.third, label %if.third.end
|
||||
if.third:
|
||||
store i32 3, i32* %i, align 4
|
||||
br label %if.third.end
|
||||
if.third.end:
|
||||
ret void
|
||||
})");
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
BasicBlock *FirstIfBody = getBasicBlockByName(F, "if.first");
|
||||
BasicBlock *SecondIfBody = getBasicBlockByName(F, "if.second");
|
||||
// Limitation: if we can prove cond haven't been modify between %0 and
|
||||
// %1, then we can prove FirstIfBody and SecondIfBody are control flow
|
||||
// equivalent.
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*FirstIfBody, *SecondIfBody, DT, PDT));
|
||||
|
||||
BasicBlock *ThirdIfBody = getBasicBlockByName(F, "if.third");
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*FirstIfBody, *ThirdIfBody, DT, PDT));
|
||||
EXPECT_FALSE(
|
||||
isControlFlowEquivalent(*SecondIfBody, *ThirdIfBody, DT, PDT));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsControlFlowEquivalentNotPostdomTest) {
|
||||
LLVMContext C;
|
||||
|
||||
// void foo(bool cond1, bool cond2) {
|
||||
// if (cond1) {
|
||||
// if (cond2)
|
||||
// return;
|
||||
// } else
|
||||
// if (cond2)
|
||||
// return;
|
||||
// return;
|
||||
// }
|
||||
std::unique_ptr<Module> M =
|
||||
parseIR(C, R"(define void @foo(i1 %cond1, i1 %cond2) {
|
||||
idom:
|
||||
br i1 %cond1, label %succ0, label %succ1
|
||||
succ0:
|
||||
br i1 %cond2, label %succ0ret, label %succ0succ1
|
||||
succ0ret:
|
||||
ret void
|
||||
succ0succ1:
|
||||
br label %bb
|
||||
succ1:
|
||||
br i1 %cond2, label %succ1ret, label %succ1succ1
|
||||
succ1ret:
|
||||
ret void
|
||||
succ1succ1:
|
||||
br label %bb
|
||||
bb:
|
||||
ret void
|
||||
})");
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
BasicBlock &Idom = F.front();
|
||||
assert(Idom.getName() == "idom" && "Expecting BasicBlock idom");
|
||||
BasicBlock &BB = F.back();
|
||||
assert(BB.getName() == "bb" && "Expecting BasicBlock bb");
|
||||
EXPECT_FALSE(isControlFlowEquivalent(Idom, BB, DT, PDT));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsSafeToMoveTest1) {
|
||||
LLVMContext C;
|
||||
|
||||
// void safecall() noexcept willreturn nosync;
|
||||
@ -65,73 +447,59 @@ TEST(CodeMoverUtils, BasicTest) {
|
||||
// }
|
||||
// }
|
||||
std::unique_ptr<Module> M = parseIR(
|
||||
C, "define void @foo(i32* noalias %A, i32* noalias %B, i32* noalias %C\n"
|
||||
" , i64 %N) {\n"
|
||||
"entry:\n"
|
||||
" %X = sdiv i64 1, %N\n"
|
||||
" call void @safecall()\n"
|
||||
" %cmp1 = icmp slt i64 0, %N\n"
|
||||
" call void @unsafecall1()\n"
|
||||
" call void @unsafecall2()\n"
|
||||
" br i1 %cmp1, label %for.body, label %for.end\n"
|
||||
"for.body:\n"
|
||||
" %i = phi i64 [ 0, %entry ], [ %inc, %for.body ]\n"
|
||||
" %arrayidx_A5 = getelementptr inbounds i32, i32* %A, i64 5\n"
|
||||
" store i32 5, i32* %arrayidx_A5, align 4\n"
|
||||
" %arrayidx_A = getelementptr inbounds i32, i32* %A, i64 %i\n"
|
||||
" store i32 0, i32* %arrayidx_A, align 4\n"
|
||||
" %load1 = load i32, i32* %arrayidx_A, align 4\n"
|
||||
" %arrayidx_B = getelementptr inbounds i32, i32* %B, i64 %i\n"
|
||||
" store i32 %load1, i32* %arrayidx_B, align 4\n"
|
||||
" %load2 = load i32, i32* %arrayidx_A, align 4\n"
|
||||
" %arrayidx_C = getelementptr inbounds i32, i32* %C, i64 %i\n"
|
||||
" store i32 %load2, i32* %arrayidx_C, align 4\n"
|
||||
" %arrayidx_A6 = getelementptr inbounds i32, i32* %A, i64 6\n"
|
||||
" store i32 6, i32* %arrayidx_A6, align 4\n"
|
||||
" %inc = add nsw i64 %i, 1\n"
|
||||
" %cmp = icmp slt i64 %inc, %N\n"
|
||||
" br i1 %cmp, label %for.body, label %for.end\n"
|
||||
"for.end:\n"
|
||||
" ret void\n"
|
||||
"}\n"
|
||||
"declare void @safecall() nounwind nosync willreturn\n"
|
||||
"declare void @unsafecall1()\n"
|
||||
"declare void @unsafecall2()\n");
|
||||
C, R"(define void @foo(i32* noalias %A, i32* noalias %B, i32* noalias %C
|
||||
, i64 %N) {
|
||||
entry:
|
||||
%X = sdiv i64 1, %N
|
||||
call void @safecall()
|
||||
%cmp1 = icmp slt i64 0, %N
|
||||
call void @unsafecall1()
|
||||
call void @unsafecall2()
|
||||
br i1 %cmp1, label %for.body, label %for.end
|
||||
for.body:
|
||||
%i = phi i64 [ 0, %entry ], [ %inc, %for.body ]
|
||||
%arrayidx_A5 = getelementptr inbounds i32, i32* %A, i64 5
|
||||
store i32 5, i32* %arrayidx_A5, align 4
|
||||
%arrayidx_A = getelementptr inbounds i32, i32* %A, i64 %i
|
||||
store i32 0, i32* %arrayidx_A, align 4
|
||||
%load1 = load i32, i32* %arrayidx_A, align 4
|
||||
%arrayidx_B = getelementptr inbounds i32, i32* %B, i64 %i
|
||||
store i32 %load1, i32* %arrayidx_B, align 4
|
||||
%load2 = load i32, i32* %arrayidx_A, align 4
|
||||
%arrayidx_C = getelementptr inbounds i32, i32* %C, i64 %i
|
||||
store i32 %load2, i32* %arrayidx_C, align 4
|
||||
%arrayidx_A6 = getelementptr inbounds i32, i32* %A, i64 6
|
||||
store i32 6, i32* %arrayidx_A6, align 4
|
||||
%inc = add nsw i64 %i, 1
|
||||
%cmp = icmp slt i64 %inc, %N
|
||||
br i1 %cmp, label %for.body, label %for.end
|
||||
for.end:
|
||||
ret void
|
||||
}
|
||||
declare void @safecall() nounwind nosync willreturn
|
||||
declare void @unsafecall1()
|
||||
declare void @unsafecall2())");
|
||||
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
Function::iterator FI = F.begin();
|
||||
BasicBlock *Entry = &*(FI++);
|
||||
assert(Entry->getName() == "entry" && "Expecting BasicBlock entry");
|
||||
BasicBlock *Entry = getBasicBlockByName(F, "entry");
|
||||
Instruction *CI_safecall = Entry->front().getNextNode();
|
||||
assert(isa<CallInst>(CI_safecall) &&
|
||||
"Expecting CI_safecall to be a CallInst");
|
||||
Instruction *CI_unsafecall = CI_safecall->getNextNode()->getNextNode();
|
||||
assert(isa<CallInst>(CI_unsafecall) &&
|
||||
"Expecting CI_unsafecall to be a CallInst");
|
||||
BasicBlock *ForBody = &*(FI++);
|
||||
assert(ForBody->getName() == "for.body" &&
|
||||
"Expecting BasicBlock for.body");
|
||||
BasicBlock *ForBody = getBasicBlockByName(F, "for.body");
|
||||
Instruction &PN = ForBody->front();
|
||||
assert(isa<PHINode>(PN) && "Expecting PN to be a PHINode");
|
||||
Instruction *SI_A5 = PN.getNextNode()->getNextNode();
|
||||
assert(isa<StoreInst>(SI_A5) &&
|
||||
SI_A5->getOperand(1)->getName() == "arrayidx_A5" &&
|
||||
"Expecting store to arrayidx_A5");
|
||||
Instruction *SI = SI_A5->getNextNode()->getNextNode();
|
||||
assert(isa<StoreInst>(SI) &&
|
||||
SI->getOperand(1)->getName() == "arrayidx_A" &&
|
||||
"Expecting store to arrayidx_A");
|
||||
Instruction *LI1 = SI->getNextNode();
|
||||
assert(LI1->getName() == "load1" && "Expecting LI1 to be load1");
|
||||
Instruction *LI2 = LI1->getNextNode()->getNextNode()->getNextNode();
|
||||
assert(LI2->getName() == "load2" && "Expecting LI2 to be load2");
|
||||
Instruction *SI_A5 =
|
||||
getInstructionByName(F, "arrayidx_A5")->getNextNode();
|
||||
Instruction *SI = getInstructionByName(F, "arrayidx_A")->getNextNode();
|
||||
Instruction *LI1 = getInstructionByName(F, "load1");
|
||||
Instruction *LI2 = getInstructionByName(F, "load2");
|
||||
Instruction *SI_A6 =
|
||||
LI2->getNextNode()->getNextNode()->getNextNode()->getNextNode();
|
||||
assert(isa<StoreInst>(SI_A6) &&
|
||||
SI_A6->getOperand(1)->getName() == "arrayidx_A6" &&
|
||||
"Expecting store to arrayidx_A6");
|
||||
getInstructionByName(F, "arrayidx_A6")->getNextNode();
|
||||
|
||||
// Can move after CI_safecall, as it does not throw, not synchronize, or
|
||||
// must return.
|
||||
@ -180,3 +548,68 @@ TEST(CodeMoverUtils, BasicTest) {
|
||||
EXPECT_TRUE(isSafeToMoveBefore(*LI2, *LI1, DT, PDT, DI));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsSafeToMoveTest2) {
|
||||
LLVMContext C;
|
||||
|
||||
std::unique_ptr<Module> M =
|
||||
parseIR(C, R"(define void @foo(i1 %cond, i32 %op0, i32 %op1) {
|
||||
entry:
|
||||
br i1 %cond, label %if.then.first, label %if.end.first
|
||||
if.then.first:
|
||||
%add = add i32 %op0, %op1
|
||||
%user = add i32 %add, 1
|
||||
br label %if.end.first
|
||||
if.end.first:
|
||||
br i1 %cond, label %if.then.second, label %if.end.second
|
||||
if.then.second:
|
||||
%sub_op0 = add i32 %op0, 1
|
||||
%sub = sub i32 %sub_op0, %op1
|
||||
br label %if.end.second
|
||||
if.end.second:
|
||||
ret void
|
||||
})");
|
||||
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
Instruction *AddInst = getInstructionByName(F, "add");
|
||||
Instruction *SubInst = getInstructionByName(F, "sub");
|
||||
|
||||
// Cannot move as %user uses %add and %sub doesn't dominates %user.
|
||||
EXPECT_FALSE(isSafeToMoveBefore(*AddInst, *SubInst, DT, PDT, DI));
|
||||
|
||||
// Cannot move as %sub_op0 is an operand of %sub and %add doesn't
|
||||
// dominates %sub_op0.
|
||||
EXPECT_FALSE(isSafeToMoveBefore(*SubInst, *AddInst, DT, PDT, DI));
|
||||
});
|
||||
}
|
||||
|
||||
TEST(CodeMoverUtils, IsSafeToMoveTest3) {
|
||||
LLVMContext C;
|
||||
|
||||
std::unique_ptr<Module> M = parseIR(C, R"(define void @foo(i64 %N) {
|
||||
entry:
|
||||
br label %for.body
|
||||
for.body:
|
||||
%i = phi i64 [ 0, %entry ], [ %inc, %for.latch ]
|
||||
%inc = add nsw i64 %i, 1
|
||||
br label %for.latch
|
||||
for.latch:
|
||||
%cmp = icmp slt i64 %inc, %N
|
||||
br i1 %cmp, label %for.body, label %for.end
|
||||
for.end:
|
||||
ret void
|
||||
})");
|
||||
|
||||
run(*M, "foo",
|
||||
[&](Function &F, DominatorTree &DT, PostDominatorTree &PDT,
|
||||
DependenceInfo &DI) {
|
||||
Instruction *IncInst = getInstructionByName(F, "inc");
|
||||
Instruction *CmpInst = getInstructionByName(F, "cmp");
|
||||
|
||||
// Can move as the incoming block of %inc for %i (%for.latch) dominated
|
||||
// by %cmp.
|
||||
EXPECT_TRUE(isSafeToMoveBefore(*IncInst, *CmpInst, DT, PDT, DI));
|
||||
});
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user