llvm/unittests/IR/DominatorTreeTest.cpp
Jakub Kuderski c9087d07bb [Dominators] Don't compute DFS InOut numbers eagerly.
Summary:
DFS InOut numbers currently get eagerly computer upon DomTree construction. They are only needed to answer dome dominance queries and they get invalidated by updates and recalculations. Because of that, it is faster in practice to compute them lazily when they are actually needed.

Clang built without this patch takes 6m 45s to boostrap on my machine, and with the patch applied 6m 38s.

Reviewers: sanjoy, dberlin, chandlerc

Reviewed By: dberlin

Subscribers: davide, llvm-commits

Differential Revision: https://reviews.llvm.org/D34296

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306778 91177308-0d34-0410-b5e6-96231b3b80d8
2017-06-30 01:28:21 +00:00

314 lines
11 KiB
C++

//===- llvm/unittests/IR/DominatorTreeTest.cpp - Constants unit tests -----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/PostDominators.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
using namespace llvm;
/// Build the dominator tree for the function and run the Test.
static void
runWithDomTree(Module &M, StringRef FuncName,
function_ref<void(Function &F, DominatorTree *DT,
DominatorTreeBase<BasicBlock> *PDT)>
Test) {
auto *F = M.getFunction(FuncName);
ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
// Compute the dominator tree for the function.
DominatorTree DT(*F);
DominatorTreeBase<BasicBlock> PDT(/*isPostDom*/ true);
PDT.recalculate(*F);
Test(*F, &DT, &PDT);
}
static std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
StringRef ModuleStr) {
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(ModuleStr, Err, Context);
assert(M && "Bad assembly?");
return M;
}
TEST(DominatorTree, Unreachable) {
StringRef ModuleString =
"declare i32 @g()\n"
"define void @f(i32 %x) personality i32 ()* @g {\n"
"bb0:\n"
" %y1 = add i32 %x, 1\n"
" %y2 = add i32 %x, 1\n"
" %y3 = invoke i32 @g() to label %bb1 unwind label %bb2\n"
"bb1:\n"
" %y4 = add i32 %x, 1\n"
" br label %bb4\n"
"bb2:\n"
" %y5 = landingpad i32\n"
" cleanup\n"
" br label %bb4\n"
"bb3:\n"
" %y6 = add i32 %x, 1\n"
" %y7 = add i32 %x, 1\n"
" ret void\n"
"bb4:\n"
" %y8 = phi i32 [0, %bb2], [%y4, %bb1]\n"
" %y9 = phi i32 [0, %bb2], [%y4, %bb1]\n"
" ret void\n"
"}\n";
// Parse the module.
LLVMContext Context;
std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
runWithDomTree(
*M, "f",
[&](Function &F, DominatorTree *DT, DominatorTreeBase<BasicBlock> *PDT) {
Function::iterator FI = F.begin();
BasicBlock *BB0 = &*FI++;
BasicBlock::iterator BBI = BB0->begin();
Instruction *Y1 = &*BBI++;
Instruction *Y2 = &*BBI++;
Instruction *Y3 = &*BBI++;
BasicBlock *BB1 = &*FI++;
BBI = BB1->begin();
Instruction *Y4 = &*BBI++;
BasicBlock *BB2 = &*FI++;
BBI = BB2->begin();
Instruction *Y5 = &*BBI++;
BasicBlock *BB3 = &*FI++;
BBI = BB3->begin();
Instruction *Y6 = &*BBI++;
Instruction *Y7 = &*BBI++;
BasicBlock *BB4 = &*FI++;
BBI = BB4->begin();
Instruction *Y8 = &*BBI++;
Instruction *Y9 = &*BBI++;
// Reachability
EXPECT_TRUE(DT->isReachableFromEntry(BB0));
EXPECT_TRUE(DT->isReachableFromEntry(BB1));
EXPECT_TRUE(DT->isReachableFromEntry(BB2));
EXPECT_FALSE(DT->isReachableFromEntry(BB3));
EXPECT_TRUE(DT->isReachableFromEntry(BB4));
// BB dominance
EXPECT_TRUE(DT->dominates(BB0, BB0));
EXPECT_TRUE(DT->dominates(BB0, BB1));
EXPECT_TRUE(DT->dominates(BB0, BB2));
EXPECT_TRUE(DT->dominates(BB0, BB3));
EXPECT_TRUE(DT->dominates(BB0, BB4));
EXPECT_FALSE(DT->dominates(BB1, BB0));
EXPECT_TRUE(DT->dominates(BB1, BB1));
EXPECT_FALSE(DT->dominates(BB1, BB2));
EXPECT_TRUE(DT->dominates(BB1, BB3));
EXPECT_FALSE(DT->dominates(BB1, BB4));
EXPECT_FALSE(DT->dominates(BB2, BB0));
EXPECT_FALSE(DT->dominates(BB2, BB1));
EXPECT_TRUE(DT->dominates(BB2, BB2));
EXPECT_TRUE(DT->dominates(BB2, BB3));
EXPECT_FALSE(DT->dominates(BB2, BB4));
EXPECT_FALSE(DT->dominates(BB3, BB0));
EXPECT_FALSE(DT->dominates(BB3, BB1));
EXPECT_FALSE(DT->dominates(BB3, BB2));
EXPECT_TRUE(DT->dominates(BB3, BB3));
EXPECT_FALSE(DT->dominates(BB3, BB4));
// BB proper dominance
EXPECT_FALSE(DT->properlyDominates(BB0, BB0));
EXPECT_TRUE(DT->properlyDominates(BB0, BB1));
EXPECT_TRUE(DT->properlyDominates(BB0, BB2));
EXPECT_TRUE(DT->properlyDominates(BB0, BB3));
EXPECT_FALSE(DT->properlyDominates(BB1, BB0));
EXPECT_FALSE(DT->properlyDominates(BB1, BB1));
EXPECT_FALSE(DT->properlyDominates(BB1, BB2));
EXPECT_TRUE(DT->properlyDominates(BB1, BB3));
EXPECT_FALSE(DT->properlyDominates(BB2, BB0));
EXPECT_FALSE(DT->properlyDominates(BB2, BB1));
EXPECT_FALSE(DT->properlyDominates(BB2, BB2));
EXPECT_TRUE(DT->properlyDominates(BB2, BB3));
EXPECT_FALSE(DT->properlyDominates(BB3, BB0));
EXPECT_FALSE(DT->properlyDominates(BB3, BB1));
EXPECT_FALSE(DT->properlyDominates(BB3, BB2));
EXPECT_FALSE(DT->properlyDominates(BB3, BB3));
// Instruction dominance in the same reachable BB
EXPECT_FALSE(DT->dominates(Y1, Y1));
EXPECT_TRUE(DT->dominates(Y1, Y2));
EXPECT_FALSE(DT->dominates(Y2, Y1));
EXPECT_FALSE(DT->dominates(Y2, Y2));
// Instruction dominance in the same unreachable BB
EXPECT_TRUE(DT->dominates(Y6, Y6));
EXPECT_TRUE(DT->dominates(Y6, Y7));
EXPECT_TRUE(DT->dominates(Y7, Y6));
EXPECT_TRUE(DT->dominates(Y7, Y7));
// Invoke
EXPECT_TRUE(DT->dominates(Y3, Y4));
EXPECT_FALSE(DT->dominates(Y3, Y5));
// Phi
EXPECT_TRUE(DT->dominates(Y2, Y9));
EXPECT_FALSE(DT->dominates(Y3, Y9));
EXPECT_FALSE(DT->dominates(Y8, Y9));
// Anything dominates unreachable
EXPECT_TRUE(DT->dominates(Y1, Y6));
EXPECT_TRUE(DT->dominates(Y3, Y6));
// Unreachable doesn't dominate reachable
EXPECT_FALSE(DT->dominates(Y6, Y1));
// Instruction, BB dominance
EXPECT_FALSE(DT->dominates(Y1, BB0));
EXPECT_TRUE(DT->dominates(Y1, BB1));
EXPECT_TRUE(DT->dominates(Y1, BB2));
EXPECT_TRUE(DT->dominates(Y1, BB3));
EXPECT_TRUE(DT->dominates(Y1, BB4));
EXPECT_FALSE(DT->dominates(Y3, BB0));
EXPECT_TRUE(DT->dominates(Y3, BB1));
EXPECT_FALSE(DT->dominates(Y3, BB2));
EXPECT_TRUE(DT->dominates(Y3, BB3));
EXPECT_FALSE(DT->dominates(Y3, BB4));
EXPECT_TRUE(DT->dominates(Y6, BB3));
// Post dominance.
EXPECT_TRUE(PDT->dominates(BB0, BB0));
EXPECT_FALSE(PDT->dominates(BB1, BB0));
EXPECT_FALSE(PDT->dominates(BB2, BB0));
EXPECT_FALSE(PDT->dominates(BB3, BB0));
EXPECT_TRUE(PDT->dominates(BB4, BB1));
// Dominance descendants.
SmallVector<BasicBlock *, 8> DominatedBBs, PostDominatedBBs;
DT->getDescendants(BB0, DominatedBBs);
PDT->getDescendants(BB0, PostDominatedBBs);
EXPECT_EQ(DominatedBBs.size(), 4UL);
EXPECT_EQ(PostDominatedBBs.size(), 1UL);
// BB3 is unreachable. It should have no dominators nor postdominators.
DominatedBBs.clear();
PostDominatedBBs.clear();
DT->getDescendants(BB3, DominatedBBs);
DT->getDescendants(BB3, PostDominatedBBs);
EXPECT_EQ(DominatedBBs.size(), 0UL);
EXPECT_EQ(PostDominatedBBs.size(), 0UL);
// Check DFS Numbers before
DT->updateDFSNumbers();
EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 7UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 2UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 5UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 6UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 3UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 4UL);
// Reattach block 3 to block 1 and recalculate
BB1->getTerminator()->eraseFromParent();
BranchInst::Create(BB4, BB3, ConstantInt::getTrue(F.getContext()), BB1);
DT->recalculate(F);
// Check DFS Numbers after
DT->updateDFSNumbers();
EXPECT_EQ(DT->getNode(BB0)->getDFSNumIn(), 0UL);
EXPECT_EQ(DT->getNode(BB0)->getDFSNumOut(), 9UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumIn(), 1UL);
EXPECT_EQ(DT->getNode(BB1)->getDFSNumOut(), 4UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumIn(), 7UL);
EXPECT_EQ(DT->getNode(BB2)->getDFSNumOut(), 8UL);
EXPECT_EQ(DT->getNode(BB3)->getDFSNumIn(), 2UL);
EXPECT_EQ(DT->getNode(BB3)->getDFSNumOut(), 3UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumIn(), 5UL);
EXPECT_EQ(DT->getNode(BB4)->getDFSNumOut(), 6UL);
// Change root node
DT->verifyDomTree();
BasicBlock *NewEntry =
BasicBlock::Create(F.getContext(), "new_entry", &F, BB0);
BranchInst::Create(BB0, NewEntry);
EXPECT_EQ(F.begin()->getName(), NewEntry->getName());
EXPECT_TRUE(&F.getEntryBlock() == NewEntry);
DT->setNewRoot(NewEntry);
DT->verifyDomTree();
});
}
TEST(DominatorTree, NonUniqueEdges) {
StringRef ModuleString =
"define i32 @f(i32 %i, i32 *%p) {\n"
"bb0:\n"
" store i32 %i, i32 *%p\n"
" switch i32 %i, label %bb2 [\n"
" i32 0, label %bb1\n"
" i32 1, label %bb1\n"
" ]\n"
" bb1:\n"
" ret i32 1\n"
" bb2:\n"
" ret i32 4\n"
"}\n";
// Parse the module.
LLVMContext Context;
std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleString);
runWithDomTree(
*M, "f",
[&](Function &F, DominatorTree *DT, DominatorTreeBase<BasicBlock> *PDT) {
Function::iterator FI = F.begin();
BasicBlock *BB0 = &*FI++;
BasicBlock *BB1 = &*FI++;
BasicBlock *BB2 = &*FI++;
const TerminatorInst *TI = BB0->getTerminator();
assert(TI->getNumSuccessors() == 3 && "Switch has three successors");
BasicBlockEdge Edge_BB0_BB2(BB0, TI->getSuccessor(0));
assert(Edge_BB0_BB2.getEnd() == BB2 &&
"Default label is the 1st successor");
BasicBlockEdge Edge_BB0_BB1_a(BB0, TI->getSuccessor(1));
assert(Edge_BB0_BB1_a.getEnd() == BB1 && "BB1 is the 2nd successor");
BasicBlockEdge Edge_BB0_BB1_b(BB0, TI->getSuccessor(2));
assert(Edge_BB0_BB1_b.getEnd() == BB1 && "BB1 is the 3rd successor");
EXPECT_TRUE(DT->dominates(Edge_BB0_BB2, BB2));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB2, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB1));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_a, BB2));
EXPECT_FALSE(DT->dominates(Edge_BB0_BB1_b, BB2));
});
}