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