//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/SimplifyCFG.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Scalar.h"
using namespace llvm;
#define DEBUG_TYPE "simplifycfg"
-STATISTIC(NumSimpl, "Number of blocks simplified");
-
-namespace {
-struct CFGSimplifyPass : public FunctionPass {
- static char ID; // Pass identification, replacement for typeid
- CFGSimplifyPass() : FunctionPass(ID) {
- initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
- }
- bool runOnFunction(Function &F) override;
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<TargetTransformInfo>();
- }
-};
-}
+static cl::opt<unsigned>
+UserBonusInstThreshold("bonus-inst-threshold", cl::Hidden, cl::init(1),
+ cl::desc("Control the number of bonus instructions (default = 1)"));
-char CFGSimplifyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
- false)
-INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
-INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
- false)
-
-// Public interface to the CFGSimplification pass
-FunctionPass *llvm::createCFGSimplificationPass() {
- return new CFGSimplifyPass();
-}
+STATISTIC(NumSimpl, "Number of blocks simplified");
-/// mergeEmptyReturnBlocks - If we have more than one empty (other than phi
-/// node) return blocks, merge them together to promote recursive block merging.
+/// If we have more than one empty (other than phi node) return blocks,
+/// merge them together to promote recursive block merging.
static bool mergeEmptyReturnBlocks(Function &F) {
bool Changed = false;
return Changed;
}
-/// iterativelySimplifyCFG - Call SimplifyCFG on all the blocks in the function,
+/// Call SimplifyCFG on all the blocks in the function,
/// iterating until no more changes are made.
static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
- const DataLayout *DL) {
+ AssumptionCache *AC,
+ unsigned BonusInstThreshold) {
bool Changed = false;
bool LocalChange = true;
while (LocalChange) {
LocalChange = false;
- // Loop over all of the basic blocks and remove them if they are unneeded...
- //
+ // Loop over all of the basic blocks and remove them if they are unneeded.
for (Function::iterator BBIt = F.begin(); BBIt != F.end(); ) {
- if (SimplifyCFG(BBIt++, TTI, DL)) {
+ if (SimplifyCFG(BBIt++, TTI, BonusInstThreshold, AC)) {
LocalChange = true;
++NumSimpl;
}
return Changed;
}
-// It is possible that we may require multiple passes over the code to fully
-// simplify the CFG.
-//
-bool CFGSimplifyPass::runOnFunction(Function &F) {
- if (skipOptnoneFunction(F))
- return false;
-
- const TargetTransformInfo &TTI = getAnalysis<TargetTransformInfo>();
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
+static bool simplifyFunctionCFG(Function &F, const TargetTransformInfo &TTI,
+ AssumptionCache *AC, int BonusInstThreshold) {
bool EverChanged = removeUnreachableBlocks(F);
EverChanged |= mergeEmptyReturnBlocks(F);
- EverChanged |= iterativelySimplifyCFG(F, TTI, DL);
+ EverChanged |= iterativelySimplifyCFG(F, TTI, AC, BonusInstThreshold);
// If neither pass changed anything, we're done.
if (!EverChanged) return false;
// iterativelySimplifyCFG can (rarely) make some loops dead. If this happens,
// removeUnreachableBlocks is needed to nuke them, which means we should
// iterate between the two optimizations. We structure the code like this to
- // avoid reruning iterativelySimplifyCFG if the second pass of
+ // avoid rerunning iterativelySimplifyCFG if the second pass of
// removeUnreachableBlocks doesn't do anything.
if (!removeUnreachableBlocks(F))
return true;
do {
- EverChanged = iterativelySimplifyCFG(F, TTI, DL);
+ EverChanged = iterativelySimplifyCFG(F, TTI, AC, BonusInstThreshold);
EverChanged |= removeUnreachableBlocks(F);
} while (EverChanged);
return true;
}
+
+SimplifyCFGPass::SimplifyCFGPass()
+ : BonusInstThreshold(UserBonusInstThreshold) {}
+
+SimplifyCFGPass::SimplifyCFGPass(int BonusInstThreshold)
+ : BonusInstThreshold(BonusInstThreshold) {}
+
+PreservedAnalyses SimplifyCFGPass::run(Function &F,
+ AnalysisManager<Function> *AM) {
+ auto &TTI = AM->getResult<TargetIRAnalysis>(F);
+ auto &AC = AM->getResult<AssumptionAnalysis>(F);
+
+ if (!simplifyFunctionCFG(F, TTI, &AC, BonusInstThreshold))
+ return PreservedAnalyses::none();
+
+ return PreservedAnalyses::all();
+}
+
+namespace {
+struct CFGSimplifyPass : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+ unsigned BonusInstThreshold;
+ std::function<bool(const Function &)> PredicateFtor;
+
+ CFGSimplifyPass(int T = -1,
+ std::function<bool(const Function &)> Ftor = nullptr)
+ : FunctionPass(ID), PredicateFtor(Ftor) {
+ BonusInstThreshold = (T == -1) ? UserBonusInstThreshold : unsigned(T);
+ initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnFunction(Function &F) override {
+ if (PredicateFtor && !PredicateFtor(F))
+ return false;
+
+ if (skipOptnoneFunction(F))
+ return false;
+
+ AssumptionCache *AC =
+ &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+ const TargetTransformInfo &TTI =
+ getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
+ return simplifyFunctionCFG(F, TTI, AC, BonusInstThreshold);
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<AssumptionCacheTracker>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
+ }
+};
+}
+
+char CFGSimplifyPass::ID = 0;
+INITIALIZE_PASS_BEGIN(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
+ false)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
+ false)
+
+// Public interface to the CFGSimplification pass
+FunctionPass *
+llvm::createCFGSimplificationPass(int Threshold,
+ std::function<bool(const Function &)> Ftor) {
+ return new CFGSimplifyPass(Threshold, Ftor);
+}
+
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