+
+PreservedAnalyses EarlyCSEPass::run(Function &F,
+ AnalysisManager<Function> *AM) {
+ auto &TLI = AM->getResult<TargetLibraryAnalysis>(F);
+ auto &TTI = AM->getResult<TargetIRAnalysis>(F);
+ auto &DT = AM->getResult<DominatorTreeAnalysis>(F);
+ auto &AC = AM->getResult<AssumptionAnalysis>(F);
+
+ EarlyCSE CSE(TLI, TTI, DT, AC);
+
+ if (!CSE.run())
+ return PreservedAnalyses::all();
+
+ // CSE preserves the dominator tree because it doesn't mutate the CFG.
+ // FIXME: Bundle this with other CFG-preservation.
+ PreservedAnalyses PA;
+ PA.preserve<DominatorTreeAnalysis>();
+ return PA;
+}
+
+namespace {
+/// \brief A simple and fast domtree-based CSE pass.
+///
+/// This pass does a simple depth-first walk over the dominator tree,
+/// eliminating trivially redundant instructions and using instsimplify to
+/// canonicalize things as it goes. It is intended to be fast and catch obvious
+/// cases so that instcombine and other passes are more effective. It is
+/// expected that a later pass of GVN will catch the interesting/hard cases.
+class EarlyCSELegacyPass : public FunctionPass {
+public:
+ static char ID;
+
+ EarlyCSELegacyPass() : FunctionPass(ID) {
+ initializeEarlyCSELegacyPassPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnFunction(Function &F) override {
+ if (skipOptnoneFunction(F))
+ return false;
+
+ auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
+ auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+ auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+
+ EarlyCSE CSE(TLI, TTI, DT, AC);
+
+ return CSE.run();
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<AssumptionCacheTracker>();
+ AU.addRequired<DominatorTreeWrapperPass>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
+ AU.addPreserved<GlobalsAAWrapperPass>();
+ AU.setPreservesCFG();
+ }
+};
+}
+
+char EarlyCSELegacyPass::ID = 0;
+
+FunctionPass *llvm::createEarlyCSEPass() { return new EarlyCSELegacyPass(); }
+
+INITIALIZE_PASS_BEGIN(EarlyCSELegacyPass, "early-cse", "Early CSE", false,
+ false)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(EarlyCSELegacyPass, "early-cse", "Early CSE", false, false)