1 //===- BasicBlockUtils.cpp - Unit tests for BasicBlockUtils ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
10 #include "llvm/Analysis/PostDominators.h"
11 #include "llvm/AsmParser/Parser.h"
12 #include "llvm/IR/BasicBlock.h"
13 #include "llvm/IR/Dominators.h"
14 #include "llvm/IR/LLVMContext.h"
15 #include "llvm/Support/SourceMgr.h"
16 #include "gtest/gtest.h"
17 
18 using namespace llvm;
19 
20 static std::unique_ptr<Module> parseIR(LLVMContext &C, const char *IR) {
21   SMDiagnostic Err;
22   std::unique_ptr<Module> Mod = parseAssemblyString(IR, Err, C);
23   if (!Mod)
24     Err.print("BasicBlockUtilsTests", errs());
25   return Mod;
26 }
27 
28 TEST(BasicBlockUtils, SplitBlockPredecessors) {
29   LLVMContext C;
30 
31   std::unique_ptr<Module> M = parseIR(
32     C,
33     "define i32 @basic_func(i1 %cond) {\n"
34     "entry:\n"
35     "  br i1 %cond, label %bb0, label %bb1\n"
36     "bb0:\n"
37     "  br label %bb1\n"
38     "bb1:\n"
39     "  %phi = phi i32 [ 0, %entry ], [ 1, %bb0 ]"
40     "  ret i32 %phi\n"
41     "}\n"
42     "\n"
43     );
44 
45   auto *F = M->getFunction("basic_func");
46   DominatorTree DT(*F);
47 
48   // Make sure the dominator tree is properly updated if calling this on the
49   // entry block.
50   SplitBlockPredecessors(&F->getEntryBlock(), {}, "split.entry", &DT);
51   EXPECT_TRUE(DT.verify());
52 }
53 
54 TEST(BasicBlockUtils, SplitCriticalEdge) {
55   LLVMContext C;
56 
57   std::unique_ptr<Module> M = parseIR(
58     C,
59     "define void @crit_edge(i1 %cond0, i1 %cond1) {\n"
60     "entry:\n"
61     "  br i1 %cond0, label %bb0, label %bb1\n"
62     "bb0:\n"
63     "  br label %bb1\n"
64     "bb1:\n"
65     "  br label %bb2\n"
66     "bb2:\n"
67     "  ret void\n"
68     "}\n"
69     "\n"
70     );
71 
72   auto *F = M->getFunction("crit_edge");
73   DominatorTree DT(*F);
74   PostDominatorTree PDT(*F);
75 
76   CriticalEdgeSplittingOptions CESO(&DT, nullptr, nullptr, &PDT);
77   EXPECT_EQ(1u, SplitAllCriticalEdges(*F, CESO));
78   EXPECT_TRUE(DT.verify());
79   EXPECT_TRUE(PDT.verify());
80 }
81