//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "loop-instsimplify"
-#include "llvm/Analysis/Dominators.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Instructions.h"
#include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/ADT/Statistic.h"
using namespace llvm;
+#define DEBUG_TYPE "loop-instsimplify"
+
STATISTIC(NumSimplified, "Number of redundant instructions simplified");
namespace {
initializeLoopInstSimplifyPass(*PassRegistry::getPassRegistry());
}
- bool runOnLoop(Loop*, LPPassManager&);
+ bool runOnLoop(Loop*, LPPassManager&) override;
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<LoopInfo>();
AU.addRequiredID(LoopSimplifyID);
+ AU.addPreservedID(LoopSimplifyID);
AU.addPreservedID(LCSSAID);
+ AU.addPreserved("scalar-evolution");
+ AU.addRequired<TargetLibraryInfo>();
}
};
}
-
+
char LoopInstSimplify::ID = 0;
INITIALIZE_PASS_BEGIN(LoopInstSimplify, "loop-instsimplify",
"Simplify instructions in loops", false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_DEPENDENCY(LCSSA)
INITIALIZE_PASS_END(LoopInstSimplify, "loop-instsimplify",
"Simplify instructions in loops", false, false)
-Pass* llvm::createLoopInstSimplifyPass() {
+Pass *llvm::createLoopInstSimplifyPass() {
return new LoopInstSimplify();
}
bool LoopInstSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
- DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>();
+ if (skipOptnoneFunction(L))
+ return false;
+
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
LoopInfo *LI = &getAnalysis<LoopInfo>();
- const TargetData *TD = getAnalysisIfAvailable<TargetData>();
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
+ const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
SmallVector<BasicBlock*, 8> ExitBlocks;
L->getUniqueExitBlocks(ExitBlocks);
SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
- SmallVector<BasicBlock*, 16> VisitStack;
+ // The bit we are stealing from the pointer represents whether this basic
+ // block is the header of a subloop, in which case we only process its phis.
+ typedef PointerIntPair<BasicBlock*, 1> WorklistItem;
+ SmallVector<WorklistItem, 16> VisitStack;
SmallPtrSet<BasicBlock*, 32> Visited;
bool Changed = false;
VisitStack.clear();
Visited.clear();
- VisitStack.push_back(L->getHeader());
+ VisitStack.push_back(WorklistItem(L->getHeader(), false));
while (!VisitStack.empty()) {
- BasicBlock *BB = VisitStack.back();
- VisitStack.pop_back();
+ WorklistItem Item = VisitStack.pop_back_val();
+ BasicBlock *BB = Item.getPointer();
+ bool IsSubloopHeader = Item.getInt();
// Simplify instructions in the current basic block.
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
// Don't bother simplifying unused instructions.
if (!I->use_empty()) {
- Value *V = SimplifyInstruction(I, TD, DT);
+ Value *V = SimplifyInstruction(I, DL, TLI, DT);
if (V && LI->replacementPreservesLCSSAForm(I, V)) {
// Mark all uses for resimplification next time round the loop.
- for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
- UI != UE; ++UI)
- Next->insert(cast<Instruction>(*UI));
+ for (User *U : I->users())
+ Next->insert(cast<Instruction>(U));
I->replaceAllUsesWith(V);
LocalChanged = true;
++NumSimplified;
}
}
- LocalChanged |= RecursivelyDeleteTriviallyDeadInstructions(I);
+ LocalChanged |= RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
+
+ if (IsSubloopHeader && !isa<PHINode>(I))
+ break;
}
- // Add all successors to the worklist, except for loop exit blocks.
+ // Add all successors to the worklist, except for loop exit blocks and the
+ // bodies of subloops. We visit the headers of loops so that we can process
+ // their phis, but we contract the rest of the subloop body and only follow
+ // edges leading back to the original loop.
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE;
++SI) {
BasicBlock *SuccBB = *SI;
+ if (!Visited.insert(SuccBB))
+ continue;
+
+ const Loop *SuccLoop = LI->getLoopFor(SuccBB);
+ if (SuccLoop && SuccLoop->getHeader() == SuccBB
+ && L->contains(SuccLoop)) {
+ VisitStack.push_back(WorklistItem(SuccBB, true));
+
+ SmallVector<BasicBlock*, 8> SubLoopExitBlocks;
+ SuccLoop->getExitBlocks(SubLoopExitBlocks);
+
+ for (unsigned i = 0; i < SubLoopExitBlocks.size(); ++i) {
+ BasicBlock *ExitBB = SubLoopExitBlocks[i];
+ if (LI->getLoopFor(ExitBB) == L && Visited.insert(ExitBB))
+ VisitStack.push_back(WorklistItem(ExitBB, false));
+ }
+
+ continue;
+ }
+
bool IsExitBlock = std::binary_search(ExitBlocks.begin(),
- ExitBlocks.end(), SuccBB);
- if (!IsExitBlock && Visited.insert(SuccBB))
- VisitStack.push_back(SuccBB);
+ ExitBlocks.end(), SuccBB);
+ if (IsExitBlock)
+ continue;
+
+ VisitStack.push_back(WorklistItem(SuccBB, false));
}
}
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