static cl::opt<unsigned>
NumShuffles("num-shuffles",
cl::desc("Number of times to shuffle and verify use-lists"),
- cl::init(5));
+ cl::init(1));
namespace {
});
}
-/// Shuffle all use-lists in a module.
-static void shuffleUseLists(Module &M, unsigned SeedOffset) {
- DEBUG(dbgs() << "*** shuffle-use-lists ***\n");
- std::minstd_rand0 Gen(std::minstd_rand0::default_seed + SeedOffset);
- DenseSet<Value *> Seen;
+static void reverseValueUseLists(Value *V, DenseSet<Value *> &Seen) {
+ if (!Seen.insert(V).second)
+ return;
+
+ if (auto *C = dyn_cast<Constant>(V))
+ if (!isa<GlobalValue>(C))
+ for (Value *Op : C->operands())
+ reverseValueUseLists(Op, Seen);
+
+ if (V->use_empty() || std::next(V->use_begin()) == V->use_end())
+ // Nothing to shuffle for 0 or 1 users.
+ return;
+
+ DEBUG({
+ dbgs() << "V = ";
+ V->dump();
+ for (const Use &U : V->uses()) {
+ dbgs() << " - order: op = " << U.getOperandNo() << ", U = ";
+ U.getUser()->dump();
+ }
+ dbgs() << " => reverse\n";
+ });
- // Shuffle the use-list of each value that would be serialized to an IR file
- // (bitcode or assembly).
- auto shuffle = [&](Value *V) { shuffleValueUseLists(V, Gen, Seen); };
+ V->reverseUseList();
+ DEBUG({
+ for (const Use &U : V->uses()) {
+ dbgs() << " - order: op = " << U.getOperandNo() << ", U = ";
+ U.getUser()->dump();
+ }
+ });
+}
+
+template <class Changer>
+static void changeUseLists(Module &M, Changer changeValueUseList) {
+ // Visit every value that would be serialized to an IR file.
+ //
// Globals.
for (GlobalVariable &G : M.globals())
- shuffle(&G);
+ changeValueUseList(&G);
for (GlobalAlias &A : M.aliases())
- shuffle(&A);
+ changeValueUseList(&A);
for (Function &F : M)
- shuffle(&F);
+ changeValueUseList(&F);
// Constants used by globals.
for (GlobalVariable &G : M.globals())
if (G.hasInitializer())
- shuffle(G.getInitializer());
+ changeValueUseList(G.getInitializer());
for (GlobalAlias &A : M.aliases())
- shuffle(A.getAliasee());
+ changeValueUseList(A.getAliasee());
for (Function &F : M)
if (F.hasPrefixData())
- shuffle(F.getPrefixData());
+ changeValueUseList(F.getPrefixData());
// Function bodies.
for (Function &F : M) {
for (Argument &A : F.args())
- shuffle(&A);
+ changeValueUseList(&A);
for (BasicBlock &BB : F)
- shuffle(&BB);
+ changeValueUseList(&BB);
for (BasicBlock &BB : F)
for (Instruction &I : BB)
- shuffle(&I);
+ changeValueUseList(&I);
// Constants used by instructions.
for (BasicBlock &BB : F)
for (Value *Op : I.operands())
if ((isa<Constant>(Op) && !isa<GlobalValue>(*Op)) ||
isa<InlineAsm>(Op))
- shuffle(Op);
+ changeValueUseList(Op);
}
+}
+
+static void shuffleUseLists(Module &M, unsigned SeedOffset) {
+ DEBUG(dbgs() << "*** shuffle-use-lists ***\n");
+ std::minstd_rand0 Gen(std::minstd_rand0::default_seed + SeedOffset);
+ DenseSet<Value *> Seen;
+ changeUseLists(M, [&](Value *V) { shuffleValueUseLists(V, Gen, Seen); });
+ DEBUG(dbgs() << "\n");
+}
+static void reverseUseLists(Module &M) {
+ DEBUG(dbgs() << "*** reverse-use-lists ***\n");
+ DenseSet<Value *> Seen;
+ changeUseLists(M, [&](Value *V) { reverseValueUseLists(V, Seen); });
DEBUG(dbgs() << "\n");
}
return 0;
}
+ // Verify the use lists now and after reversing them.
+ verifyUseListOrder(*M);
+ reverseUseLists(*M);
+ verifyUseListOrder(*M);
+
for (unsigned I = 0, E = NumShuffles; I != E; ++I) {
DEBUG(dbgs() << "*** iteration: " << I << " ***\n");
- // Shuffle with a different seed each time so that use-lists that aren't
- // modified the first time are likely to be modified the next time.
+ // Shuffle with a different (deterministic) seed each time.
shuffleUseLists(*M, I);
+
+ // Verify again before and after reversing.
+ verifyUseListOrder(*M);
+ reverseUseLists(*M);
verifyUseListOrder(*M);
}