[ValueTracking] Make unit tests easier to write; NFC

Generalize the existing MatchSelectPatternTest class to also work
with other types of tests. This reduces the amount of boilerplate
necessary to write ValueTracking tests in general, and computeKnownBits
tests in particular.

The inherited convention is that the function must be @test and the
tested instruction %A.

Differential Revision: https://reviews.llvm.org/D55141

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348043 91177308-0d34-0410-b5e6-96231b3b80d8

Author: nikic

unittests/Analysis/ValueTrackingTest.cpp

@@ -22,7 +22,7 @@ using namespace llvm;
 
 namespace {
 
-class MatchSelectPatternTest : public testing::Test {
+class ValueTrackingTest : public testing::Test {
 protected:
   void parseAssembly(const char *Assembly) {
     SMDiagnostic Error;
@@ -51,6 +51,13 @@ class MatchSelectPatternTest : public testing::Test {
       report_fatal_error("@test must have an instruction %A");
   }
 
+  LLVMContext Context;
+  std::unique_ptr<Module> M;
+  Instruction *A;
+};
+
+class MatchSelectPatternTest : public ValueTrackingTest {
+protected:
   void expectPattern(const SelectPatternResult &P) {
     Value *LHS, *RHS;
     Instruction::CastOps CastOp;
@@ -59,10 +66,16 @@ class MatchSelectPatternTest : public testing::Test {
     EXPECT_EQ(P.NaNBehavior, R.NaNBehavior);
     EXPECT_EQ(P.Ordered, R.Ordered);
   }
+};
 
-  LLVMContext Context;
-  std::unique_ptr<Module> M;
-  Instruction *A, *B;
+class ComputeKnownBitsTest : public ValueTrackingTest {
+protected:
+  void expectKnownBits(uint64_t Zero, uint64_t One) {
+    auto Known = computeKnownBits(A, M->getDataLayout());
+    ASSERT_FALSE(Known.hasConflict());
+    EXPECT_EQ(Known.One.getZExtValue(), One);
+    EXPECT_EQ(Known.Zero.getZExtValue(), Zero);
+  }
 };
 
 }
@@ -497,117 +510,61 @@ TEST(ValueTracking, GuaranteedToTransferExecutionToSuccessor) {
   }
 }
 
-TEST(ValueTracking, ComputeNumSignBits_PR32045) {
-  StringRef Assembly = "define i32 @f(i32 %a) { "
-                       "  %val = ashr i32 %a, -1 "
-                       "  ret i32 %val "
-                       "} ";
-
-  LLVMContext Context;
-  SMDiagnostic Error;
-  auto M = parseAssemblyString(Assembly, Error, Context);
-  assert(M && "Bad assembly?");
-
-  auto *F = M->getFunction("f");
-  assert(F && "Bad assembly?");
-
-  auto *RVal =
-      cast<ReturnInst>(F->getEntryBlock().getTerminator())->getOperand(0);
-  EXPECT_EQ(ComputeNumSignBits(RVal, M->getDataLayout()), 1u);
+TEST_F(ValueTrackingTest, ComputeNumSignBits_PR32045) {
+  parseAssembly(
+      "define i32 @test(i32 %a) {\n"
+      "  %A = ashr i32 %a, -1\n"
+      "  ret i32 %A\n"
+      "}\n");
+  EXPECT_EQ(ComputeNumSignBits(A, M->getDataLayout()), 1u);
 }
 
 // No guarantees for canonical IR in this analysis, so this just bails out. 
-TEST(ValueTracking, ComputeNumSignBits_Shuffle) {
-  StringRef Assembly = "define <2 x i32> @f() { "
-                       "  %val = shufflevector <2 x i32> undef, <2 x i32> undef, <2 x i32> <i32 0, i32 0> "
-                       "  ret <2 x i32> %val "
-                       "} ";
-
-  LLVMContext Context;
-  SMDiagnostic Error;
-  auto M = parseAssemblyString(Assembly, Error, Context);
-  assert(M && "Bad assembly?");
-
-  auto *F = M->getFunction("f");
-  assert(F && "Bad assembly?");
-
-  auto *RVal =
-      cast<ReturnInst>(F->getEntryBlock().getTerminator())->getOperand(0);
-  EXPECT_EQ(ComputeNumSignBits(RVal, M->getDataLayout()), 1u);
+TEST_F(ValueTrackingTest, ComputeNumSignBits_Shuffle) {
+  parseAssembly(
+      "define <2 x i32> @test() {\n"
+      "  %A = shufflevector <2 x i32> undef, <2 x i32> undef, <2 x i32> <i32 0, i32 0>\n"
+      "  ret <2 x i32> %A\n"
+      "}\n");
+  EXPECT_EQ(ComputeNumSignBits(A, M->getDataLayout()), 1u);
 }
 
 // No guarantees for canonical IR in this analysis, so a shuffle element that
 // references an undef value means this can't return any extra information. 
-TEST(ValueTracking, ComputeNumSignBits_Shuffle2) {
-  StringRef Assembly = "define <2 x i32> @f(<2 x i1> %x) { "
-                       "  %sext = sext <2 x i1> %x to <2 x i32> "
-                       "  %val = shufflevector <2 x i32> %sext, <2 x i32> undef, <2 x i32> <i32 0, i32 2> "
-                       "  ret <2 x i32> %val "
-                       "} ";
-
-  LLVMContext Context;
-  SMDiagnostic Error;
-  auto M = parseAssemblyString(Assembly, Error, Context);
-  assert(M && "Bad assembly?");
-
-  auto *F = M->getFunction("f");
-  assert(F && "Bad assembly?");
-
-  auto *RVal =
-      cast<ReturnInst>(F->getEntryBlock().getTerminator())->getOperand(0);
-  EXPECT_EQ(ComputeNumSignBits(RVal, M->getDataLayout()), 1u);
+TEST_F(ValueTrackingTest, ComputeNumSignBits_Shuffle2) {
+  parseAssembly(
+      "define <2 x i32> @test(<2 x i1> %x) {\n"
+      "  %sext = sext <2 x i1> %x to <2 x i32>\n"
+      "  %A = shufflevector <2 x i32> %sext, <2 x i32> undef, <2 x i32> <i32 0, i32 2>\n"
+      "  ret <2 x i32> %A\n"
+      "}\n");
+  EXPECT_EQ(ComputeNumSignBits(A, M->getDataLayout()), 1u);
 }
 
-TEST(ValueTracking, ComputeKnownBits) {
-  StringRef Assembly = "define i32 @f(i32 %a, i32 %b) { "
-                       "  %ash = mul i32 %a, 8 "
-                       "  %aad = add i32 %ash, 7 "
-                       "  %aan = and i32 %aad, 4095 "
-                       "  %bsh = shl i32 %b, 4 "
-                       "  %bad = or i32 %bsh, 6 "
-                       "  %ban = and i32 %bad, 4095 "
-                       "  %mul = mul i32 %aan, %ban "
-                       "  ret i32 %mul "
-                       "} ";
-
-  LLVMContext Context;
-  SMDiagnostic Error;
-  auto M = parseAssemblyString(Assembly, Error, Context);
-  assert(M && "Bad assembly?");
-
-  auto *F = M->getFunction("f");
-  assert(F && "Bad assembly?");
-
-  auto *RVal =
-      cast<ReturnInst>(F->getEntryBlock().getTerminator())->getOperand(0);
-  auto Known = computeKnownBits(RVal, M->getDataLayout());
-  ASSERT_FALSE(Known.hasConflict());
-  EXPECT_EQ(Known.One.getZExtValue(), 10u);
-  EXPECT_EQ(Known.Zero.getZExtValue(), 4278190085u);
+TEST_F(ComputeKnownBitsTest, ComputeKnownBits) {
+  parseAssembly(
+      "define i32 @test(i32 %a, i32 %b) {\n"
+      "  %ash = mul i32 %a, 8\n"
+      "  %aad = add i32 %ash, 7\n"
+      "  %aan = and i32 %aad, 4095\n"
+      "  %bsh = shl i32 %b, 4\n"
+      "  %bad = or i32 %bsh, 6\n"
+      "  %ban = and i32 %bad, 4095\n"
+      "  %A = mul i32 %aan, %ban\n"
+      "  ret i32 %A\n"
+      "}\n");
+  expectKnownBits(/*zero*/ 4278190085u, /*one*/ 10u);
 }
 
-TEST(ValueTracking, ComputeKnownMulBits) {
-  StringRef Assembly = "define i32 @f(i32 %a, i32 %b) { "
-                       "  %aa = shl i32 %a, 5 "
-                       "  %bb = shl i32 %b, 5 "
-                       "  %aaa = or i32 %aa, 24 "
-                       "  %bbb = or i32 %bb, 28 "
-                       "  %mul = mul i32 %aaa, %bbb "
-                       "  ret i32 %mul "
-                       "} ";
-
-  LLVMContext Context;
-  SMDiagnostic Error;
-  auto M = parseAssemblyString(Assembly, Error, Context);
-  assert(M && "Bad assembly?");
-
-  auto *F = M->getFunction("f");
-  assert(F && "Bad assembly?");
-
-  auto *RVal =
-      cast<ReturnInst>(F->getEntryBlock().getTerminator())->getOperand(0);
-  auto Known = computeKnownBits(RVal, M->getDataLayout());
-  ASSERT_FALSE(Known.hasConflict());
-  EXPECT_EQ(Known.One.getZExtValue(), 32u);
-  EXPECT_EQ(Known.Zero.getZExtValue(), 95u);
+TEST_F(ComputeKnownBitsTest, ComputeKnownMulBits) {
+  parseAssembly(
+      "define i32 @test(i32 %a, i32 %b) {\n"
+      "  %aa = shl i32 %a, 5\n"
+      "  %bb = shl i32 %b, 5\n"
+      "  %aaa = or i32 %aa, 24\n"
+      "  %bbb = or i32 %bb, 28\n"
+      "  %A = mul i32 %aaa, %bbb\n"
+      "  ret i32 %A\n"
+      "}\n");
+  expectKnownBits(/*zero*/ 95u, /*one*/ 32u);
 }