[turbofan] Improve code generation for inline comparisons with zero.

TEST=cctest,unittests
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/669133004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24832 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compiler/instruction-selector.h

@@ -85,20 +85,10 @@ class InstructionSelector FINAL {
     return Features(CpuFeatures::SupportedFeatures());
   }
 
-  // Checks if {node} is currently live.
-  bool IsLive(Node* node) const { return !IsDefined(node) && IsUsed(node); }
-
- private:
-  friend class OperandGenerator;
-
   // ===========================================================================
   // ============ Architecture-independent graph covering methods. =============
   // ===========================================================================
 
-  // Checks if {block} will appear directly after {current_block_} when
-  // assembling code, in which case, a fall-through can be used.
-  bool IsNextInAssemblyOrder(const BasicBlock* block) const;
-
   // Used in pattern matching during code generation.
   // Check if {node} can be covered while generating code for the current
   // instruction. A node can be covered if the {user} of the node has the only
@@ -109,13 +99,23 @@ class InstructionSelector FINAL {
   // generated for it.
   bool IsDefined(Node* node) const;
 
-  // Inform the instruction selection that {node} was just defined.
-  void MarkAsDefined(Node* node);
-
   // Checks if {node} has any uses, and therefore code has to be generated for
   // it.
   bool IsUsed(Node* node) const;
 
+  // Checks if {node} is currently live.
+  bool IsLive(Node* node) const { return !IsDefined(node) && IsUsed(node); }
+
+ private:
+  friend class OperandGenerator;
+
+  // Checks if {block} will appear directly after {current_block_} when
+  // assembling code, in which case, a fall-through can be used.
+  bool IsNextInAssemblyOrder(const BasicBlock* block) const;
+
+  // Inform the instruction selection that {node} was just defined.
+  void MarkAsDefined(Node* node);
+
   // Inform the instruction selection that {node} has at least one use and we
   // will need to generate code for it.
   void MarkAsUsed(Node* node);

src/compiler/machine-operator-reducer.cc

@@ -243,6 +243,21 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
       if (m.LeftEqualsRight()) return ReplaceBool(true);  // x == x => true
       break;
     }
+    case IrOpcode::kWord64Equal: {
+      Int64BinopMatcher m(node);
+      if (m.IsFoldable()) {  // K == K => K
+        return ReplaceBool(m.left().Value() == m.right().Value());
+      }
+      if (m.left().IsInt64Sub() && m.right().Is(0)) {  // x - y == 0 => x == y
+        Int64BinopMatcher msub(m.left().node());
+        node->ReplaceInput(0, msub.left().node());
+        node->ReplaceInput(1, msub.right().node());
+        return Changed(node);
+      }
+      // TODO(turbofan): fold HeapConstant, ExternalReference, pointer compares
+      if (m.LeftEqualsRight()) return ReplaceBool(true);  // x == x => true
+      break;
+    }
     case IrOpcode::kInt32Add: {
       Int32BinopMatcher m(node);
       if (m.right().Is(0)) return Replace(m.left().node());  // x + 0 => x

src/compiler/simplified-lowering.cc

@@ -456,8 +456,8 @@ class RepresentationSelector {
         if (lower()) {
           MachineTypeUnion input = GetInfo(node->InputAt(0))->output;
           if (input & kRepBit) {
-            // BooleanNot(x: kRepBit) => WordEqual(x, #0)
-            node->set_op(lowering->machine()->WordEqual());
+            // BooleanNot(x: kRepBit) => Word32Equal(x, #0)
+            node->set_op(lowering->machine()->Word32Equal());
             node->AppendInput(jsgraph_->zone(), jsgraph_->Int32Constant(0));
           } else {
             // BooleanNot(x: kRepTagged) => WordEqual(x, #false)

src/compiler/typer.cc

@@ -1044,7 +1044,7 @@ Bounds Typer::Visitor::TypeBooleanNot(Node* node) {
 
 
 Bounds Typer::Visitor::TypeBooleanToNumber(Node* node) {
-  return Bounds(Type::None(zone()), Type::Number(zone()));
+  return Bounds(Type::None(zone()), typer_->zero_or_one);
 }
 
 

src/compiler/x64/instruction-selector-x64.cc

@@ -821,6 +821,14 @@ static void VisitWordCompare(InstructionSelector* selector, Node* node,
 }
 
 
+// Shared routine for comparison with zero.
+static void VisitCompareZero(InstructionSelector* selector, Node* node,
+                             InstructionCode opcode, FlagsContinuation* cont) {
+  X64OperandGenerator g(selector);
+  VisitCompare(selector, opcode, g.Use(node), g.TempImmediate(0), cont);
+}
+
+
 // Shared routine for multiple float64 compare operations.
 static void VisitFloat64Compare(InstructionSelector* selector, Node* node,
                                 FlagsContinuation* cont) {
@@ -946,16 +954,30 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
   }
 
   // Branch could not be combined with a compare, emit compare against 0.
-  VisitCompare(this, kX64Cmp32, g.Use(value), g.TempImmediate(0), &cont);
+  VisitCompareZero(this, value, kX64Cmp32, &cont);
 }
 
 
 void InstructionSelector::VisitWord32Equal(Node* const node) {
-  Node* const user = node;
+  Node* user = node;
   FlagsContinuation cont(kEqual, node);
   Int32BinopMatcher m(user);
   if (m.right().Is(0)) {
-    Node* const value = m.left().node();
+    Node* value = m.left().node();
+
+    // Try to combine with comparisons against 0 by simply inverting the branch.
+    while (CanCover(user, value) && value->opcode() == IrOpcode::kWord32Equal) {
+      Int32BinopMatcher m(value);
+      if (m.right().Is(0)) {
+        user = value;
+        value = m.left().node();
+        cont.Negate();
+      } else {
+        break;
+      }
+    }
+
+    // Try to combine the branch with a comparison.
     if (CanCover(user, value)) {
       switch (value->opcode()) {
         case IrOpcode::kInt32Sub:
@@ -966,6 +988,7 @@ void InstructionSelector::VisitWord32Equal(Node* const node) {
           break;
       }
     }
+    return VisitCompareZero(this, value, kX64Cmp32, &cont);
   }
   VisitWordCompare(this, node, kX64Cmp32, &cont);
 }
@@ -996,11 +1019,25 @@ void InstructionSelector::VisitUint32LessThanOrEqual(Node* node) {
 
 
 void InstructionSelector::VisitWord64Equal(Node* const node) {
-  Node* const user = node;
+  Node* user = node;
   FlagsContinuation cont(kEqual, node);
   Int64BinopMatcher m(user);
   if (m.right().Is(0)) {
-    Node* const value = m.left().node();
+    Node* value = m.left().node();
+
+    // Try to combine with comparisons against 0 by simply inverting the branch.
+    while (CanCover(user, value) && value->opcode() == IrOpcode::kWord64Equal) {
+      Int64BinopMatcher m(value);
+      if (m.right().Is(0)) {
+        user = value;
+        value = m.left().node();
+        cont.Negate();
+      } else {
+        break;
+      }
+    }
+
+    // Try to combine the branch with a comparison.
     if (CanCover(user, value)) {
       switch (value->opcode()) {
         case IrOpcode::kInt64Sub:
@@ -1011,6 +1048,7 @@ void InstructionSelector::VisitWord64Equal(Node* const node) {
           break;
       }
     }
+    return VisitCompareZero(this, value, kX64Cmp, &cont);
   }
   VisitWordCompare(this, node, kX64Cmp, &cont);
 }

test/cctest/compiler/test-run-machops.cc

@@ -556,6 +556,142 @@ TEST(RunInt32AddP) {
 }
 
 
+TEST(RunInt32AddAndWord32EqualP) {
+  {
+    RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32, kMachInt32);
+    m.Return(m.Int32Add(m.Parameter(0),
+                        m.Word32Equal(m.Parameter(1), m.Parameter(2))));
+    FOR_INT32_INPUTS(i) {
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>(bit_cast<uint32_t>(*i) + (*j == *k));
+          CHECK_EQ(expected, m.Call(*i, *j, *k));
+        }
+      }
+    }
+  }
+  {
+    RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32, kMachInt32);
+    m.Return(m.Int32Add(m.Word32Equal(m.Parameter(0), m.Parameter(1)),
+                        m.Parameter(2)));
+    FOR_INT32_INPUTS(i) {
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>((*i == *j) + bit_cast<uint32_t>(*k));
+          CHECK_EQ(expected, m.Call(*i, *j, *k));
+        }
+      }
+    }
+  }
+}
+
+
+TEST(RunInt32AddAndWord32EqualImm) {
+  {
+    FOR_INT32_INPUTS(i) {
+      RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32);
+      m.Return(m.Int32Add(m.Int32Constant(*i),
+                          m.Word32Equal(m.Parameter(0), m.Parameter(1))));
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>(bit_cast<uint32_t>(*i) + (*j == *k));
+          CHECK_EQ(expected, m.Call(*j, *k));
+        }
+      }
+    }
+  }
+  {
+    FOR_INT32_INPUTS(i) {
+      RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32);
+      m.Return(m.Int32Add(m.Word32Equal(m.Int32Constant(*i), m.Parameter(0)),
+                          m.Parameter(1)));
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>((*i == *j) + bit_cast<uint32_t>(*k));
+          CHECK_EQ(expected, m.Call(*j, *k));
+        }
+      }
+    }
+  }
+}
+
+
+TEST(RunInt32AddAndWord32NotEqualP) {
+  {
+    RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32, kMachInt32);
+    m.Return(m.Int32Add(m.Parameter(0),
+                        m.Word32NotEqual(m.Parameter(1), m.Parameter(2))));
+    FOR_INT32_INPUTS(i) {
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>(bit_cast<uint32_t>(*i) + (*j != *k));
+          CHECK_EQ(expected, m.Call(*i, *j, *k));
+        }
+      }
+    }
+  }
+  {
+    RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32, kMachInt32);
+    m.Return(m.Int32Add(m.Word32NotEqual(m.Parameter(0), m.Parameter(1)),
+                        m.Parameter(2)));
+    FOR_INT32_INPUTS(i) {
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>((*i != *j) + bit_cast<uint32_t>(*k));
+          CHECK_EQ(expected, m.Call(*i, *j, *k));
+        }
+      }
+    }
+  }
+}
+
+
+TEST(RunInt32AddAndWord32NotEqualImm) {
+  {
+    FOR_INT32_INPUTS(i) {
+      RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32);
+      m.Return(m.Int32Add(m.Int32Constant(*i),
+                          m.Word32NotEqual(m.Parameter(0), m.Parameter(1))));
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>(bit_cast<uint32_t>(*i) + (*j != *k));
+          CHECK_EQ(expected, m.Call(*j, *k));
+        }
+      }
+    }
+  }
+  {
+    FOR_INT32_INPUTS(i) {
+      RawMachineAssemblerTester<int32_t> m(kMachInt32, kMachInt32);
+      m.Return(m.Int32Add(m.Word32NotEqual(m.Int32Constant(*i), m.Parameter(0)),
+                          m.Parameter(1)));
+      FOR_INT32_INPUTS(j) {
+        FOR_INT32_INPUTS(k) {
+          // Use uint32_t because signed overflow is UB in C.
+          int32_t const expected =
+              bit_cast<int32_t>((*i != *j) + bit_cast<uint32_t>(*k));
+          CHECK_EQ(expected, m.Call(*j, *k));
+        }
+      }
+    }
+  }
+}
+
+
 TEST(RunInt32AddAndWord32SarP) {
   {
     RawMachineAssemblerTester<int32_t> m(kMachUint32, kMachInt32, kMachUint32);

test/cctest/compiler/test-simplified-lowering.cc

@@ -791,7 +791,7 @@ TEST(LowerBooleanNot_bit_bit) {
   Node* use = t.Branch(inv);
   t.Lower();
   Node* cmp = use->InputAt(0);
-  CHECK_EQ(t.machine()->WordEqual()->opcode(), cmp->opcode());
+  CHECK_EQ(t.machine()->Word32Equal()->opcode(), cmp->opcode());
   CHECK(b == cmp->InputAt(0) || b == cmp->InputAt(1));
   Node* f = t.jsgraph.Int32Constant(0);
   CHECK(f == cmp->InputAt(0) || f == cmp->InputAt(1));
@@ -808,7 +808,7 @@ TEST(LowerBooleanNot_bit_tagged) {
   t.Lower();
   CHECK_EQ(IrOpcode::kChangeBitToBool, use->InputAt(0)->opcode());
   Node* cmp = use->InputAt(0)->InputAt(0);
-  CHECK_EQ(t.machine()->WordEqual()->opcode(), cmp->opcode());
+  CHECK_EQ(t.machine()->Word32Equal()->opcode(), cmp->opcode());
   CHECK(b == cmp->InputAt(0) || b == cmp->InputAt(1));
   Node* f = t.jsgraph.Int32Constant(0);
   CHECK(f == cmp->InputAt(0) || f == cmp->InputAt(1));

test/unittests/compiler/arm/instruction-selector-arm-unittest.cc

@@ -1371,6 +1371,113 @@ TEST_F(InstructionSelectorTest, TruncateFloat64ToFloat32WithParameter) {
 }
 
 
+// -----------------------------------------------------------------------------
+// Comparisons.
+
+
+namespace {
+
+struct Comparison {
+  Constructor constructor;
+  const char* constructor_name;
+  FlagsCondition flags_condition;
+  FlagsCondition negated_flags_condition;
+};
+
+
+std::ostream& operator<<(std::ostream& os, const Comparison& cmp) {
+  return os << cmp.constructor_name;
+}
+
+
+const Comparison kComparisons[] = {
+    {&RawMachineAssembler::Word32Equal, "Word32Equal", kEqual, kNotEqual},
+    {&RawMachineAssembler::Int32LessThan, "Int32LessThan", kSignedLessThan,
+     kSignedGreaterThanOrEqual},
+    {&RawMachineAssembler::Int32LessThanOrEqual, "Int32LessThanOrEqual",
+     kSignedLessThanOrEqual, kSignedGreaterThan},
+    {&RawMachineAssembler::Uint32LessThan, "Uint32LessThan", kUnsignedLessThan,
+     kUnsignedGreaterThanOrEqual},
+    {&RawMachineAssembler::Uint32LessThanOrEqual, "Uint32LessThanOrEqual",
+     kUnsignedLessThanOrEqual, kUnsignedGreaterThan}};
+
+}  // namespace
+
+
+typedef InstructionSelectorTestWithParam<Comparison>
+    InstructionSelectorComparisonTest;
+
+
+TEST_P(InstructionSelectorComparisonTest, Parameters) {
+  const Comparison& cmp = GetParam();
+  StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32);
+  Node* const p0 = m.Parameter(0);
+  Node* const p1 = m.Parameter(1);
+  Node* const r = (m.*cmp.constructor)(p0, p1);
+  m.Return(r);
+  Stream const s = m.Build();
+  ASSERT_EQ(1U, s.size());
+  EXPECT_EQ(kArmCmp, s[0]->arch_opcode());
+  EXPECT_EQ(kMode_Operand2_R, s[0]->addressing_mode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+  EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
+  ASSERT_EQ(1U, s[0]->OutputCount());
+  EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->OutputAt(0)));
+  EXPECT_EQ(kFlags_set, s[0]->flags_mode());
+  EXPECT_EQ(cmp.flags_condition, s[0]->flags_condition());
+}
+
+
+TEST_P(InstructionSelectorComparisonTest, Word32EqualWithZero) {
+  {
+    const Comparison& cmp = GetParam();
+    StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const p1 = m.Parameter(1);
+    Node* const r =
+        m.Word32Equal((m.*cmp.constructor)(p0, p1), m.Int32Constant(0));
+    m.Return(r);
+    Stream const s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArmCmp, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_Operand2_R, s[0]->addressing_mode());
+    ASSERT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->OutputAt(0)));
+    EXPECT_EQ(kFlags_set, s[0]->flags_mode());
+    EXPECT_EQ(cmp.negated_flags_condition, s[0]->flags_condition());
+  }
+  {
+    const Comparison& cmp = GetParam();
+    StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const p1 = m.Parameter(1);
+    Node* const r =
+        m.Word32Equal(m.Int32Constant(0), (m.*cmp.constructor)(p0, p1));
+    m.Return(r);
+    Stream const s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArmCmp, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_Operand2_R, s[0]->addressing_mode());
+    ASSERT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->OutputAt(0)));
+    EXPECT_EQ(kFlags_set, s[0]->flags_mode());
+    EXPECT_EQ(cmp.negated_flags_condition, s[0]->flags_condition());
+  }
+}
+
+
+INSTANTIATE_TEST_CASE_P(InstructionSelectorTest,
+                        InstructionSelectorComparisonTest,
+                        ::testing::ValuesIn(kComparisons));
+
+
 // -----------------------------------------------------------------------------
 // Miscellaneous.