forked from OSchip/llvm-project
277 lines
7.6 KiB
C++
277 lines
7.6 KiB
C++
//===- BasicBlockUtils.cpp - Unit tests for BasicBlockUtils ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Analysis/BlockFrequencyInfo.h"
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#include "llvm/Analysis/BranchProbabilityInfo.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/PostDominators.h"
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#include "llvm/AsmParser/Parser.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/Support/SourceMgr.h"
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#include "gtest/gtest.h"
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using namespace llvm;
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static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
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SMDiagnostic Err;
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std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
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if (!Mod)
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Err.print("BasicBlockUtilsTests", errs());
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return Mod;
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}
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TEST(BasicBlockUtils, EliminateUnreachableBlocks) {
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LLVMContext C;
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std::unique_ptr<Module> M = parseIR(
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C,
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"define i32 @has_unreachable(i1 %cond) {\n"
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"entry:\n"
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" br i1 %cond, label %bb0, label %bb1\n"
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"bb0:\n"
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" br label %bb1\n"
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"bb1:\n"
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" %phi = phi i32 [ 0, %entry ], [ 1, %bb0 ]"
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" ret i32 %phi\n"
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"bb2:\n"
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" ret i32 42\n"
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"}\n"
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"\n"
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);
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auto *F = M->getFunction("has_unreachable");
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DominatorTree DT(*F);
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DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
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EXPECT_EQ(F->size(), (size_t)4);
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bool Result = EliminateUnreachableBlocks(*F, &DTU);
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EXPECT_TRUE(Result);
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EXPECT_EQ(F->size(), (size_t)3);
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EXPECT_TRUE(DT.verify());
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}
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TEST(BasicBlockUtils, NoUnreachableBlocksToEliminate) {
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LLVMContext C;
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std::unique_ptr<Module> M = parseIR(
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C,
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"define i32 @no_unreachable(i1 %cond) {\n"
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"entry:\n"
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" br i1 %cond, label %bb0, label %bb1\n"
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"bb0:\n"
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" br label %bb1\n"
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"bb1:\n"
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" %phi = phi i32 [ 0, %entry ], [ 1, %bb0 ]"
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" ret i32 %phi\n"
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"}\n"
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"\n"
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);
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auto *F = M->getFunction("no_unreachable");
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DominatorTree DT(*F);
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DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
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EXPECT_EQ(F->size(), (size_t)3);
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bool Result = EliminateUnreachableBlocks(*F, &DTU);
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EXPECT_FALSE(Result);
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EXPECT_EQ(F->size(), (size_t)3);
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EXPECT_TRUE(DT.verify());
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}
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TEST(BasicBlockUtils, SplitBlockPredecessors) {
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LLVMContext C;
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std::unique_ptr<Module> M = parseIR(
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C,
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"define i32 @basic_func(i1 %cond) {\n"
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"entry:\n"
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" br i1 %cond, label %bb0, label %bb1\n"
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"bb0:\n"
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" br label %bb1\n"
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"bb1:\n"
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" %phi = phi i32 [ 0, %entry ], [ 1, %bb0 ]"
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" ret i32 %phi\n"
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"}\n"
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"\n"
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);
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auto *F = M->getFunction("basic_func");
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DominatorTree DT(*F);
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// Make sure the dominator tree is properly updated if calling this on the
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// entry block.
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SplitBlockPredecessors(&F->getEntryBlock(), {}, "split.entry", &DT);
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EXPECT_TRUE(DT.verify());
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}
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TEST(BasicBlockUtils, SplitCriticalEdge) {
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LLVMContext C;
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std::unique_ptr<Module> M = parseIR(
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C,
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"define void @crit_edge(i1 %cond0, i1 %cond1) {\n"
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"entry:\n"
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" br i1 %cond0, label %bb0, label %bb1\n"
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"bb0:\n"
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" br label %bb1\n"
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"bb1:\n"
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" br label %bb2\n"
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"bb2:\n"
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" ret void\n"
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"}\n"
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"\n"
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);
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auto *F = M->getFunction("crit_edge");
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DominatorTree DT(*F);
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PostDominatorTree PDT(*F);
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CriticalEdgeSplittingOptions CESO(&DT, nullptr, nullptr, &PDT);
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EXPECT_EQ(1u, SplitAllCriticalEdges(*F, CESO));
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EXPECT_TRUE(DT.verify());
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EXPECT_TRUE(PDT.verify());
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}
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TEST(BasicBlockUtils, SplitIndirectBrCriticalEdge) {
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LLVMContext C;
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std::unique_ptr<Module> M =
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parseIR(C, "define void @crit_edge(i8* %cond0, i1 %cond1) {\n"
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"entry:\n"
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" indirectbr i8* %cond0, [label %bb0, label %bb1]\n"
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"bb0:\n"
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" br label %bb1\n"
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"bb1:\n"
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" %p = phi i32 [0, %bb0], [0, %entry]\n"
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" br i1 %cond1, label %bb2, label %bb3\n"
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"bb2:\n"
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" ret void\n"
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"bb3:\n"
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" ret void\n"
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"}\n");
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auto *F = M->getFunction("crit_edge");
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DominatorTree DT(*F);
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LoopInfo LI(DT);
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BranchProbabilityInfo BPI(*F, LI);
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BlockFrequencyInfo BFI(*F, BPI, LI);
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auto Block = [&F](StringRef BBName) -> const BasicBlock & {
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for (auto &BB : *F)
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if (BB.getName() == BBName)
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return BB;
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llvm_unreachable("Block not found");
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};
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bool Split = SplitIndirectBrCriticalEdges(*F, &BPI, &BFI);
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EXPECT_TRUE(Split);
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// Check that successors of the split block get their probability correct.
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BasicBlock *SplitBB = Block("bb1").getTerminator()->getSuccessor(0);
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EXPECT_EQ(2u, SplitBB->getTerminator()->getNumSuccessors());
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EXPECT_EQ(BranchProbability(1, 2), BPI.getEdgeProbability(SplitBB, 0u));
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EXPECT_EQ(BranchProbability(1, 2), BPI.getEdgeProbability(SplitBB, 1u));
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}
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TEST(BasicBlockUtils, SetEdgeProbability) {
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LLVMContext C;
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std::unique_ptr<Module> M = parseIR(
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C, "define void @edge_probability(i32 %0) {\n"
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"entry:\n"
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"switch i32 %0, label %LD [\n"
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" i32 700, label %L0\n"
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" i32 701, label %L1\n"
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" i32 702, label %L2\n"
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" i32 703, label %L3\n"
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" i32 704, label %L4\n"
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" i32 705, label %L5\n"
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" i32 706, label %L6\n"
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" i32 707, label %L7\n"
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" i32 708, label %L8\n"
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" i32 709, label %L9\n"
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" i32 710, label %L10\n"
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" i32 711, label %L11\n"
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" i32 712, label %L12\n"
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" i32 713, label %L13\n"
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" i32 714, label %L14\n"
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" i32 715, label %L15\n"
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" i32 716, label %L16\n"
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" i32 717, label %L17\n"
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" i32 718, label %L18\n"
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" i32 719, label %L19\n"
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"], !prof !{!\"branch_weights\", i32 1, i32 1, i32 1, i32 1, i32 1, "
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"i32 451, i32 1, i32 12, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, "
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"i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1}\n"
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"LD:\n"
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" unreachable\n"
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"L0:\n"
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" ret void\n"
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"L1:\n"
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" ret void\n"
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"L2:\n"
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" ret void\n"
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"L3:\n"
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" ret void\n"
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"L4:\n"
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" ret void\n"
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"L5:\n"
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" ret void\n"
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"L6:\n"
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" ret void\n"
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"L7:\n"
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" ret void\n"
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"L8:\n"
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" ret void\n"
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"L9:\n"
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" ret void\n"
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"L10:\n"
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" ret void\n"
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"L11:\n"
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" ret void\n"
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"L12:\n"
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" ret void\n"
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"L13:\n"
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" ret void\n"
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"L14:\n"
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" ret void\n"
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"L15:\n"
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" ret void\n"
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"L16:\n"
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" ret void\n"
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"L17:\n"
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" ret void\n"
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"L18:\n"
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" ret void\n"
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"L19:\n"
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" ret void\n"
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"}\n");
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auto *F = M->getFunction("edge_probability");
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DominatorTree DT(*F);
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LoopInfo LI(DT);
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BranchProbabilityInfo BPI(*F, LI);
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auto Block = [&F](StringRef BBName) -> const BasicBlock & {
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for (auto &BB : *F)
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if (BB.getName() == BBName)
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return BB;
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llvm_unreachable("Block not found");
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};
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// Check that the unreachable block has the minimal probability.
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const BasicBlock &EntryBB = Block("entry");
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const BasicBlock &UnreachableBB = Block("LD");
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EXPECT_EQ(BranchProbability::getRaw(1),
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BPI.getEdgeProbability(&EntryBB, &UnreachableBB));
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}
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