unittests/Analysis/UnrollAnalyzerTest.cpp

   1 //===- UnrollAnalyzerTest.cpp - UnrollAnalyzer unit tests -----------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  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/Support/SourceMgr.h"
  15 #include "gtest/gtest.h"
  16
  17 using namespace llvm;
  18 namespace llvm {
  19 void initializeUnrollAnalyzerTestPass(PassRegistry &);
  20
  21 static SmallVector<DenseMap<Value *, Constant *>, 16> SimplifiedValuesVector;
  22 static unsigned TripCount = 0;
  23
  24 namespace {
  25 struct UnrollAnalyzerTest : public FunctionPass {
  26   static char ID;
  27   bool runOnFunction(Function &F) override {
  28     LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
  29     ScalarEvolution *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
  30
  31     Function::iterator FI = F.begin();
  32     FI++; // First basic block is entry - skip it.
  33     BasicBlock *Header = &*FI++;
  34     Loop *L = LI->getLoopFor(Header);
  35     BasicBlock *Exiting = L->getExitingBlock();
  36
  37     SimplifiedValuesVector.clear();
  38     TripCount = SE->getSmallConstantTripCount(L, Exiting);
  39     for (unsigned Iteration = 0; Iteration < TripCount; Iteration++) {
  40       DenseMap<Value *, Constant *> SimplifiedValues;
  41       UnrolledInstAnalyzer Analyzer(Iteration, SimplifiedValues, *SE, L);
  42       for (auto *BB : L->getBlocks())
  43         for (Instruction &I : *BB)
  44           Analyzer.visit(I);
  45       SimplifiedValuesVector.push_back(SimplifiedValues);
  46     }
  47     return false;
  48   }
  49   void getAnalysisUsage(AnalysisUsage &AU) const override {
  50     AU.addRequired<DominatorTreeWrapperPass>();
  51     AU.addRequired<LoopInfoWrapperPass>();
  52     AU.addRequired<ScalarEvolutionWrapperPass>();
  53     AU.setPreservesAll();
  54   }
  55   UnrollAnalyzerTest() : FunctionPass(ID) {
  56     initializeUnrollAnalyzerTestPass(*PassRegistry::getPassRegistry());
  57   }
  58 };
  59 }
  60
  61 char UnrollAnalyzerTest::ID = 0;
  62
  63 std::unique_ptr<Module> makeLLVMModule(LLVMContext &Context,
  64                                        const char *ModuleStr) {
  65   SMDiagnostic Err;
  66   return parseAssemblyString(ModuleStr, Err, Context);
  67 }
  68
  69 TEST(UnrollAnalyzerTest, BasicSimplifications) {
  70   const char *ModuleStr =
  71       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
  72       "define i64 @propagate_loop_phis() {\n"
  73       "entry:\n"
  74       "  br label %loop\n"
  75       "loop:\n"
  76       "  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]\n"
  77       "  %x0 = phi i64 [ 0, %entry ], [ %x2, %loop ]\n"
  78       "  %x1 = or i64 %x0, 1\n"
  79       "  %x2 = or i64 %x1, 2\n"
  80       "  %inc = add nuw nsw i64 %iv, 1\n"
  81       "  %cond = icmp sge i64 %inc, 8\n"
  82       "  br i1 %cond, label %loop.end, label %loop\n"
  83       "loop.end:\n"
  84       "  %x.lcssa = phi i64 [ %x2, %loop ]\n"
  85       "  ret i64 %x.lcssa\n"
  86       "}\n";
  87   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
  88   LLVMContext Context;
  89   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
  90   legacy::PassManager Passes;
  91   Passes.add(P);
  92   Passes.run(*M);
  93
  94   // Perform checks
  95   Module::iterator MI = M->begin();
  96   Function *F = &*MI++;
  97   Function::iterator FI = F->begin();
  98   FI++; // First basic block is entry - skip it.
  99   BasicBlock *Header = &*FI++;
 100
 101   BasicBlock::iterator BBI = Header->begin();
 102   std::advance(BBI, 4);
 103   Instruction *Y1 = &*BBI++;
 104   Instruction *Y2 = &*BBI++;
 105   // Check simplification expected on the 1st iteration.
 106   // Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 1
 107   auto I1 = SimplifiedValuesVector[0].find(Y1);
 108   EXPECT_TRUE(I1 != SimplifiedValuesVector[0].end());
 109   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 1U);
 110
 111   // Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
 112   auto I2 = SimplifiedValuesVector[0].find(Y2);
 113   EXPECT_TRUE(I2 != SimplifiedValuesVector[0].end());
 114   EXPECT_FALSE(cast<ConstantInt>((*I2).second)->getZExtValue());
 115
 116   // Check simplification expected on the last iteration.
 117   // Check that "%inc = add nuw nsw i64 %iv, 1" is simplified to 8
 118   I1 = SimplifiedValuesVector[TripCount - 1].find(Y1);
 119   EXPECT_TRUE(I1 != SimplifiedValuesVector[TripCount - 1].end());
 120   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), TripCount);
 121
 122   // Check that "%cond = icmp sge i64 %inc, 10" is simplified to false
 123   I2 = SimplifiedValuesVector[TripCount - 1].find(Y2);
 124   EXPECT_TRUE(I2 != SimplifiedValuesVector[TripCount - 1].end());
 125   EXPECT_TRUE(cast<ConstantInt>((*I2).second)->getZExtValue());
 126 }
 127
 128 TEST(UnrollAnalyzerTest, OuterLoopSimplification) {
 129   const char *ModuleStr =
 130       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 131       "define void @foo() {\n"
 132       "entry:\n"
 133       "  br label %outer.loop\n"
 134       "outer.loop:\n"
 135       "  %iv.outer = phi i64 [ 0, %entry ], [ %iv.outer.next, %outer.loop.latch ]\n"
 136       "  %iv.outer.next = add nuw nsw i64 %iv.outer, 1\n"
 137       "  br label %inner.loop\n"
 138       "inner.loop:\n"
 139       "  %iv.inner = phi i64 [ 0, %outer.loop ], [ %iv.inner.next, %inner.loop ]\n"
 140       "  %iv.inner.next = add nuw nsw i64 %iv.inner, 1\n"
 141       "  %exitcond.inner = icmp eq i64 %iv.inner.next, 1000\n"
 142       "  br i1 %exitcond.inner, label %outer.loop.latch, label %inner.loop\n"
 143       "outer.loop.latch:\n"
 144       "  %exitcond.outer = icmp eq i64 %iv.outer.next, 40\n"
 145       "  br i1 %exitcond.outer, label %exit, label %outer.loop\n"
 146       "exit:\n"
 147       "  ret void\n"
 148       "}\n";
 149
 150   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 151   LLVMContext Context;
 152   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 153   legacy::PassManager Passes;
 154   Passes.add(P);
 155   Passes.run(*M);
 156
 157   Module::iterator MI = M->begin();
 158   Function *F = &*MI++;
 159   Function::iterator FI = F->begin();
 160   FI++;
 161   BasicBlock *Header = &*FI++;
 162   BasicBlock *InnerBody = &*FI++;
 163
 164   BasicBlock::iterator BBI = Header->begin();
 165   BBI++;
 166   Instruction *Y1 = &*BBI;
 167   BBI = InnerBody->begin();
 168   BBI++;
 169   Instruction *Y2 = &*BBI;
 170   // Check that we can simplify IV of the outer loop, but can't simplify the IV
 171   // of the inner loop if we only know the iteration number of the outer loop.
 172   //
 173   //  Y1 is %iv.outer.next, Y2 is %iv.inner.next
 174   auto I1 = SimplifiedValuesVector[0].find(Y1);
 175   EXPECT_TRUE(I1 != SimplifiedValuesVector[0].end());
 176   auto I2 = SimplifiedValuesVector[0].find(Y2);
 177   EXPECT_TRUE(I2 == SimplifiedValuesVector[0].end());
 178 }
 179 TEST(UnrollAnalyzerTest, CmpSimplifications) {
 180   const char *ModuleStr =
 181       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 182       "define void @branch_iv_trunc() {\n"
 183       "entry:\n"
 184       "  br label %for.body\n"
 185       "for.body:\n"
 186       "  %indvars.iv = phi i64 [ 0, %entry ], [ %tmp3, %for.body ]\n"
 187       "  %tmp2 = trunc i64 %indvars.iv to i32\n"
 188       "  %cmp3 = icmp eq i32 %tmp2, 5\n"
 189       "  %tmp3 = add nuw nsw i64 %indvars.iv, 1\n"
 190       "  %exitcond = icmp eq i64 %tmp3, 10\n"
 191       "  br i1 %exitcond, label %for.end, label %for.body\n"
 192       "for.end:\n"
 193       "  ret void\n"
 194       "}\n";
 195   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 196   LLVMContext Context;
 197   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 198   legacy::PassManager Passes;
 199   Passes.add(P);
 200   Passes.run(*M);
 201
 202   // Perform checks
 203   Module::iterator MI = M->begin();
 204   Function *F = &*MI++;
 205   Function::iterator FI = F->begin();
 206   FI++; // First basic block is entry - skip it.
 207   BasicBlock *Header = &*FI++;
 208
 209   BasicBlock::iterator BBI = Header->begin();
 210   BBI++;
 211   Instruction *Y1 = &*BBI++;
 212   Instruction *Y2 = &*BBI++;
 213   // Check simplification expected on the 5th iteration.
 214   // Check that "%tmp2 = trunc i64 %indvars.iv to i32" is simplified to 5
 215   // and "%cmp3 = icmp eq i32 %tmp2, 5" is simplified to 1 (i.e. true).
 216   auto I1 = SimplifiedValuesVector[5].find(Y1);
 217   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 218   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 5U);
 219   auto I2 = SimplifiedValuesVector[5].find(Y2);
 220   EXPECT_TRUE(I2 != SimplifiedValuesVector[5].end());
 221   EXPECT_EQ(cast<ConstantInt>((*I2).second)->getZExtValue(), 1U);
 222 }
 223 TEST(UnrollAnalyzerTest, PtrCmpSimplifications) {
 224   const char *ModuleStr =
 225       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 226       "define void @ptr_cmp(i8 *%a) {\n"
 227       "entry:\n"
 228       "  %limit = getelementptr i8, i8* %a, i64 40\n"
 229       "  %start.iv2 = getelementptr i8, i8* %a, i64 7\n"
 230       "  br label %loop.body\n"
 231       "loop.body:\n"
 232       "  %iv.0 = phi i8* [ %a, %entry ], [ %iv.1, %loop.body ]\n"
 233       "  %iv2.0 = phi i8* [ %start.iv2, %entry ], [ %iv2.1, %loop.body ]\n"
 234       "  %cmp = icmp eq i8* %iv2.0, %iv.0\n"
 235       "  %iv.1 = getelementptr inbounds i8, i8* %iv.0, i64 1\n"
 236       "  %iv2.1 = getelementptr inbounds i8, i8* %iv2.0, i64 1\n"
 237       "  %exitcond = icmp ne i8* %iv.1, %limit\n"
 238       "  br i1 %exitcond, label %loop.body, label %loop.exit\n"
 239       "loop.exit:\n"
 240       "  ret void\n"
 241       "}\n";
 242   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 243   LLVMContext Context;
 244   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 245   legacy::PassManager Passes;
 246   Passes.add(P);
 247   Passes.run(*M);
 248
 249   // Perform checks
 250   Module::iterator MI = M->begin();
 251   Function *F = &*MI++;
 252   Function::iterator FI = F->begin();
 253   FI++; // First basic block is entry - skip it.
 254   BasicBlock *Header = &*FI;
 255
 256   BasicBlock::iterator BBI = Header->begin();
 257   std::advance(BBI, 2);
 258   Instruction *Y1 = &*BBI;
 259   // Check simplification expected on the 5th iteration.
 260   // Check that "%cmp = icmp eq i8* %iv2.0, %iv.0" is simplified to 0.
 261   auto I1 = SimplifiedValuesVector[5].find(Y1);
 262   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 263   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 0U);
 264 }
 265 TEST(UnrollAnalyzerTest, CastSimplifications) {
 266   const char *ModuleStr =
 267       "target datalayout = \"e-m:o-i64:64-f80:128-n8:16:32:64-S128\"\n"
 268       "@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"
 269       "define void @const_load_cast() {\n"
 270       "entry:\n"
 271       "  br label %loop\n"
 272       "\n"
 273       "loop:\n"
 274       "  %iv = phi i64 [ 0, %entry ], [ %inc, %loop ]\n"
 275       "  %array_const_idx = getelementptr inbounds [10 x i32], [10 x i32]* @known_constant, i64 0, i64 %iv\n"
 276       "  %const_array_element = load i32, i32* %array_const_idx, align 4\n"
 277       "  %se = sext i32 %const_array_element to i64\n"
 278       "  %ze = zext i32 %const_array_element to i64\n"
 279       "  %tr = trunc i32 %const_array_element to i8\n"
 280       "  %inc = add nuw nsw i64 %iv, 1\n"
 281       "  %exitcond86.i = icmp eq i64 %inc, 10\n"
 282       "  br i1 %exitcond86.i, label %loop.end, label %loop\n"
 283       "\n"
 284       "loop.end:\n"
 285       "  ret void\n"
 286       "}\n";
 287
 288   UnrollAnalyzerTest *P = new UnrollAnalyzerTest();
 289   LLVMContext Context;
 290   std::unique_ptr<Module> M = makeLLVMModule(Context, ModuleStr);
 291   legacy::PassManager Passes;
 292   Passes.add(P);
 293   Passes.run(*M);
 294
 295   // Perform checks
 296   Module::iterator MI = M->begin();
 297   Function *F = &*MI++;
 298   Function::iterator FI = F->begin();
 299   FI++; // First basic block is entry - skip it.
 300   BasicBlock *Header = &*FI++;
 301
 302   BasicBlock::iterator BBI = Header->begin();
 303   std::advance(BBI, 3);
 304   Instruction *Y1 = &*BBI++;
 305   Instruction *Y2 = &*BBI++;
 306   Instruction *Y3 = &*BBI++;
 307   // Check simplification expected on the 5th iteration.
 308   // "%se = sext i32 %const_array_element to i64" should be simplified to 259,
 309   // "%ze = zext i32 %const_array_element to i64" should be simplified to 259,
 310   // "%tr = trunc i32 %const_array_element to i8" should be simplified to 3.
 311   auto I1 = SimplifiedValuesVector[5].find(Y1);
 312   EXPECT_TRUE(I1 != SimplifiedValuesVector[5].end());
 313   EXPECT_EQ(cast<ConstantInt>((*I1).second)->getZExtValue(), 259U);
 314   auto I2 = SimplifiedValuesVector[5].find(Y2);
 315   EXPECT_TRUE(I2 != SimplifiedValuesVector[5].end());
 316   EXPECT_EQ(cast<ConstantInt>((*I2).second)->getZExtValue(), 259U);
 317   auto I3 = SimplifiedValuesVector[5].find(Y3);
 318   EXPECT_TRUE(I3 != SimplifiedValuesVector[5].end());
 319   EXPECT_EQ(cast<ConstantInt>((*I3).second)->getZExtValue(), 3U);
 320 }
 321
 322 } // end namespace llvm
 323
 324 INITIALIZE_PASS_BEGIN(UnrollAnalyzerTest, "unrollanalyzertestpass",
 325                       "unrollanalyzertestpass", false, false)
 326 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 327 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 328 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
 329 INITIALIZE_PASS_END(UnrollAnalyzerTest, "unrollanalyzertestpass",
 330                     "unrollanalyzertestpass", false, false)