unittests/Analysis/UnrollAnalyzerTest.cpp

   1 //===- UnrollAnalyzerTest.cpp - UnrollAnalyzer unit tests -----------------===//
   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/Analysis/LoopUnrollAnalyzer.h"
  10 #include "llvm/AsmParser/Parser.h"
  11 #include "llvm/IR/Dominators.h"
  12 #include "llvm/IR/LegacyPassManager.h"
  13 #include "llvm/Support/SourceMgr.h"
  14 #include "gtest/gtest.h"
  15
  16 using namespace llvm;
  17 namespace llvm {
  18 void initializeUnrollAnalyzerTestPass(PassRegistry &);
  19
  20 static SmallVector<DenseMap<Value *, Constant *>, 16> SimplifiedValuesVector;
  21 static unsigned TripCount = 0;
  22
  23 namespace {
  24 struct UnrollAnalyzerTest : public FunctionPass {
  25   static char ID;
  26   bool runOnFunction(Function &F) override {
  27     LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
  28     ScalarEvolution *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
  29
  30     Function::iterator FI = F.begin();
  31     FI++; // First basic block is entry - skip it.
  32     BasicBlock *Header = &*FI++;
  33     Loop *L = LI->getLoopFor(Header);
  34     BasicBlock *Exiting = L->getExitingBlock();
  35
  36     SimplifiedValuesVector.clear();
  37     TripCount = SE->getSmallConstantTripCount(L, Exiting);
  38     for (unsigned Iteration = 0; Iteration < TripCount; Iteration++) {
  39       DenseMap<Value *, Constant *> SimplifiedValues;
  40       UnrolledInstAnalyzer Analyzer(Iteration, SimplifiedValues, *SE, L);
  41       for (auto *BB : L->getBlocks())
  42         for (Instruction &I : *BB)
  43           Analyzer.visit(I);
  44       SimplifiedValuesVector.push_back(SimplifiedValues);
  45     }
  46     return false;
  47   }
  48   void getAnalysisUsage(AnalysisUsage &AU) const override {
  49     AU.addRequired<DominatorTreeWrapperPass>();
  50     AU.addRequired<LoopInfoWrapperPass>();
  51     AU.addRequired<ScalarEvolutionWrapperPass>();
  52     AU.setPreservesAll();
  53   }
  54   UnrollAnalyzerTest() : FunctionPass(ID) {
  55     initializeUnrollAnalyzerTestPass(*PassRegistry::getPassRegistry());
  56   }
  57 };
  58 }
  59
  60 char UnrollAnalyzerTest::ID = 0;
  61
  62 std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
  63                                        const char *ModuleStr) {
  64   SMDiagnostic Err;
  65   return parseAssemblyString(ModuleStr, Err, Context);
  66 }
  67
  68 TEST(UnrollAnalyzerTest, BasicSimplifications) {
  69   const char *ModuleStr =
  70       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
  71       "define i64 @propagate_loop_phis() {\n"
  72       "entry:\n"
  73       "  br label %loop\n"
  74       "loop:\n"
  75       "  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]\n"
  76       "  %x0 = phi i64 [ 0, %entry ], [ %x2, %loop ]\n"
  77       "  %x1 = or i64 %x0, 1\n"
  78       "  %x2 = or i64 %x1, 2\n"
  79       "  %inc = add nuw nsw i64 %iv, 1\n"
  80       "  %cond = icmp sge i64 %inc, 8\n"
  81       "  br i1 %cond, label %loop.end, label %loop\n"
  82       "loop.end:\n"
  83       "  %x.lcssa = phi i64 [ %x2, %loop ]\n"
  84       "  ret i64 %x.lcssa\n"
  85       "}\n";
  86   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
  87   LLVMContext Context;
  88   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
  89   legacy::PassManager Passes;
  90   Passes.add(P);
  91   Passes.run(*M);
  92
  93   // Perform checks
  94   Module::iterator MI = M->begin();
  95   Function *F = &*MI++;
  96   Function::iterator FI = F->begin();
  97   FI++; // First basic block is entry - skip it.
  98   BasicBlock *Header = &*FI++;
  99
 100   BasicBlock::iterator BBI = Header->begin();
 101   std::advance(BBI, 4);
 102   Instruction *Y1 = &*BBI++;
 103   Instruction *Y2 = &*BBI++;
 104   // Check simplification expected on the 1st iteration.
 105   // Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 1
 106   auto I1 = SimplifiedValuesVector[0].find(Y1);
 107   EXPECT_TRUE(I1 != SimplifiedValuesVector[0].end());
 108   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 1U);
 109
 110   // Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
 111   auto I2 = SimplifiedValuesVector[0].find(Y2);
 112   EXPECT_TRUE(I2 != SimplifiedValuesVector[0].end());
 113   EXPECT_FALSE(cast<ConstantInt>((*I2).second)->getZExtValue());
 114
 115   // Check simplification expected on the last iteration.
 116   // Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 8
 117   I1 = SimplifiedValuesVector[TripCount - 1].find(Y1);
 118   EXPECT_TRUE(I1 != SimplifiedValuesVector[TripCount - 1].end());
 119   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), TripCount);
 120
 121   // Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
 122   I2 = SimplifiedValuesVector[TripCount - 1].find(Y2);
 123   EXPECT_TRUE(I2 != SimplifiedValuesVector[TripCount - 1].end());
 124   EXPECT_TRUE(cast<ConstantInt>((*I2).second)->getZExtValue());
 125 }
 126
 127 TEST(UnrollAnalyzerTest, OuterLoopSimplification) {
 128   const char *ModuleStr =
 129       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 130       "define void @foo() {\n"
 131       "entry:\n"
 132       "  br label %outer.loop\n"
 133       "outer.loop:\n"
 134       "  %iv.outer = phi i64 [ 0, %entry ], [ %iv.outer.next, %outer.loop.latch ]\n"
 135       "  %iv.outer.next = add nuw nsw i64 %iv.outer, 1\n"
 136       "  br label %inner.loop\n"
 137       "inner.loop:\n"
 138       "  %iv.inner = phi i64 [ 0, %outer.loop ], [ %iv.inner.next, %inner.loop ]\n"
 139       "  %iv.inner.next = add nuw nsw i64 %iv.inner, 1\n"
 140       "  %exitcond.inner = icmp eq i64 %iv.inner.next, 1000\n"
 141       "  br i1 %exitcond.inner, label %outer.loop.latch, label %inner.loop\n"
 142       "outer.loop.latch:\n"
 143       "  %exitcond.outer = icmp eq i64 %iv.outer.next, 40\n"
 144       "  br i1 %exitcond.outer, label %exit, label %outer.loop\n"
 145       "exit:\n"
 146       "  ret void\n"
 147       "}\n";
 148
 149   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 150   LLVMContext Context;
 151   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 152   legacy::PassManager Passes;
 153   Passes.add(P);
 154   Passes.run(*M);
 155
 156   Module::iterator MI = M->begin();
 157   Function *F = &*MI++;
 158   Function::iterator FI = F->begin();
 159   FI++;
 160   BasicBlock *Header = &*FI++;
 161   BasicBlock *InnerBody = &*FI++;
 162
 163   BasicBlock::iterator BBI = Header->begin();
 164   BBI++;
 165   Instruction *Y1 = &*BBI;
 166   BBI = InnerBody->begin();
 167   BBI++;
 168   Instruction *Y2 = &*BBI;
 169   // Check that we can simplify IV of the outer loop, but can't simplify the IV
 170   // of the inner loop if we only know the iteration number of the outer loop.
 171   //
 172   //  Y1 is %iv.outer.next, Y2 is %iv.inner.next
 173   auto I1 = SimplifiedValuesVector[0].find(Y1);
 174   EXPECT_TRUE(I1 != SimplifiedValuesVector[0].end());
 175   auto I2 = SimplifiedValuesVector[0].find(Y2);
 176   EXPECT_TRUE(I2 == SimplifiedValuesVector[0].end());
 177 }
 178 TEST(UnrollAnalyzerTest, CmpSimplifications) {
 179   const char *ModuleStr =
 180       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 181       "define void @branch_iv_trunc() {\n"
 182       "entry:\n"
 183       "  br label %for.body\n"
 184       "for.body:\n"
 185       "  %indvars.iv = phi i64 [ 0, %entry ], [ %tmp3, %for.body ]\n"
 186       "  %tmp2 = trunc i64 %indvars.iv to i32\n"
 187       "  %cmp3 = icmp eq i32 %tmp2, 5\n"
 188       "  %tmp3 = add nuw nsw i64 %indvars.iv, 1\n"
 189       "  %exitcond = icmp eq i64 %tmp3, 10\n"
 190       "  br i1 %exitcond, label %for.end, label %for.body\n"
 191       "for.end:\n"
 192       "  ret void\n"
 193       "}\n";
 194   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 195   LLVMContext Context;
 196   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 197   legacy::PassManager Passes;
 198   Passes.add(P);
 199   Passes.run(*M);
 200
 201   // Perform checks
 202   Module::iterator MI = M->begin();
 203   Function *F = &*MI++;
 204   Function::iterator FI = F->begin();
 205   FI++; // First basic block is entry - skip it.
 206   BasicBlock *Header = &*FI++;
 207
 208   BasicBlock::iterator BBI = Header->begin();
 209   BBI++;
 210   Instruction *Y1 = &*BBI++;
 211   Instruction *Y2 = &*BBI++;
 212   // Check simplification expected on the 5th iteration.
 213   // Check that "%tmp2 = trunc i64 %indvars.iv to i32" is simplified to 5
 214   // and "%cmp3 = icmp eq i32 %tmp2, 5" is simplified to 1 (i.e. true).
 215   auto I1 = SimplifiedValuesVector[5].find(Y1);
 216   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 217   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 5U);
 218   auto I2 = SimplifiedValuesVector[5].find(Y2);
 219   EXPECT_TRUE(I2 != SimplifiedValuesVector[5].end());
 220   EXPECT_EQ(cast<ConstantInt>((*I2).second)->getZExtValue(), 1U);
 221 }
 222 TEST(UnrollAnalyzerTest, PtrCmpSimplifications) {
 223   const char *ModuleStr =
 224       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 225       "define void @ptr_cmp(i8 *%a) {\n"
 226       "entry:\n"
 227       "  %limit = getelementptr i8, i8* %a, i64 40\n"
 228       "  %start.iv2 = getelementptr i8, i8* %a, i64 7\n"
 229       "  br label %loop.body\n"
 230       "loop.body:\n"
 231       "  %iv.0 = phi i8* [ %a, %entry ], [ %iv.1, %loop.body ]\n"
 232       "  %iv2.0 = phi i8* [ %start.iv2, %entry ], [ %iv2.1, %loop.body ]\n"
 233       "  %cmp = icmp eq i8* %iv2.0, %iv.0\n"
 234       "  %iv.1 = getelementptr inbounds i8, i8* %iv.0, i64 1\n"
 235       "  %iv2.1 = getelementptr inbounds i8, i8* %iv2.0, i64 1\n"
 236       "  %exitcond = icmp ne i8* %iv.1, %limit\n"
 237       "  br i1 %exitcond, label %loop.body, label %loop.exit\n"
 238       "loop.exit:\n"
 239       "  ret void\n"
 240       "}\n";
 241   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 242   LLVMContext Context;
 243   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 244   legacy::PassManager Passes;
 245   Passes.add(P);
 246   Passes.run(*M);
 247
 248   // Perform checks
 249   Module::iterator MI = M->begin();
 250   Function *F = &*MI++;
 251   Function::iterator FI = F->begin();
 252   FI++; // First basic block is entry - skip it.
 253   BasicBlock *Header = &*FI;
 254
 255   BasicBlock::iterator BBI = Header->begin();
 256   std::advance(BBI, 2);
 257   Instruction *Y1 = &*BBI;
 258   // Check simplification expected on the 5th iteration.
 259   // Check that "%cmp = icmp eq i8* %iv2.0, %iv.0" is simplified to 0.
 260   auto I1 = SimplifiedValuesVector[5].find(Y1);
 261   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 262   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 0U);
 263 }
 264 TEST(UnrollAnalyzerTest, CastSimplifications) {
 265   const char *ModuleStr =
 266       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 267       "@known_constant = internal unnamed_addr constant [10 x i32] [i32 0, i32 1, i32 0, i32 1, i32 0, i32 259, i32 0, i32 1, i32 0, i32 1], align 16\n"
 268       "define void @const_load_cast() {\n"
 269       "entry:\n"
 270       "  br label %loop\n"
 271       "\n"
 272       "loop:\n"
 273       "  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]\n"
 274       "  %array_const_idx = getelementptr inbounds [10 x i32], [10 x i32]* @known_constant, i64 0, i64 %iv\n"
 275       "  %const_array_element = load i32, i32* %array_const_idx, align 4\n"
 276       "  %se = sext i32 %const_array_element to i64\n"
 277       "  %ze = zext i32 %const_array_element to i64\n"
 278       "  %tr = trunc i32 %const_array_element to i8\n"
 279       "  %inc = add nuw nsw i64 %iv, 1\n"
 280       "  %exitcond86.i = icmp eq i64 %inc, 10\n"
 281       "  br i1 %exitcond86.i, label %loop.end, label %loop\n"
 282       "\n"
 283       "loop.end:\n"
 284       "  ret void\n"
 285       "}\n";
 286
 287   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 288   LLVMContext Context;
 289   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 290   legacy::PassManager Passes;
 291   Passes.add(P);
 292   Passes.run(*M);
 293
 294   // Perform checks
 295   Module::iterator MI = M->begin();
 296   Function *F = &*MI++;
 297   Function::iterator FI = F->begin();
 298   FI++; // First basic block is entry - skip it.
 299   BasicBlock *Header = &*FI++;
 300
 301   BasicBlock::iterator BBI = Header->begin();
 302   std::advance(BBI, 3);
 303   Instruction *Y1 = &*BBI++;
 304   Instruction *Y2 = &*BBI++;
 305   Instruction *Y3 = &*BBI++;
 306   // Check simplification expected on the 5th iteration.
 307   // "%se = sext i32 %const_array_element to i64" should be simplified to 259,
 308   // "%ze = zext i32 %const_array_element to i64" should be simplified to 259,
 309   // "%tr = trunc i32 %const_array_element to i8" should be simplified to 3.
 310   auto I1 = SimplifiedValuesVector[5].find(Y1);
 311   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 312   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 259U);
 313   auto I2 = SimplifiedValuesVector[5].find(Y2);
 314   EXPECT_TRUE(I2 != SimplifiedValuesVector[5].end());
 315   EXPECT_EQ(cast<ConstantInt>((*I2).second)->getZExtValue(), 259U);
 316   auto I3 = SimplifiedValuesVector[5].find(Y3);
 317   EXPECT_TRUE(I3 != SimplifiedValuesVector[5].end());
 318   EXPECT_EQ(cast<ConstantInt>((*I3).second)->getZExtValue(), 3U);
 319 }
 320
 321 } // end namespace llvm
 322
 323 INITIALIZE_PASS_BEGIN(UnrollAnalyzerTest, "unrollanalyzertestpass",
 324                       "unrollanalyzertestpass", false, false)
 325 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 326 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 327 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
 328 INITIALIZE_PASS_END(UnrollAnalyzerTest, "unrollanalyzertestpass",
 329                     "unrollanalyzertestpass", false, false)