[turbofan] Strength reduction for inline comparisons.

test/unittests/compiler/machine-operator-reducer-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/compiler/typer.h"
 #include "test/unittests/compiler/graph-unittest.h"
@@ skipping 215 matching lines @@
 const uint32_t kUint32Values[] = {
     0x00000000, 0x00000001, 0xffffffff, 0x1b09788b, 0x04c5fce8, 0xcc0de5bf,
     0x273a798e, 0x187937a3, 0xece3af83, 0x5495a16b, 0x0b668ecc, 0x11223344,
     0x0000009e, 0x00000043, 0x0000af73, 0x0000116b, 0x00658ecc, 0x002b3b4c,
     0x88776655, 0x70000000, 0x07200000, 0x7fffffff, 0x56123761, 0x7fffff00,
     0x761c4761, 0x80000000, 0x88888888, 0xa0000000, 0xdddddddd, 0xe0000000,
     0xeeeeeeee, 0xfffffffd, 0xf0000000, 0x007fffff, 0x003fffff, 0x001fffff,
     0x000fffff, 0x0007ffff, 0x0003ffff, 0x0001ffff, 0x0000ffff, 0x00007fff,
     0x00003fff, 0x00001fff, 0x00000fff, 0x000007ff, 0x000003ff, 0x000001ff};
 
+
+struct ComparisonBinaryOperator {
+  const Operator* (MachineOperatorBuilder::*constructor)();
+  const char* constructor_name;
+};
+
+
+std::ostream& operator<<(std::ostream& os,
+                         ComparisonBinaryOperator const& cbop) {
+  return os << cbop.constructor_name;
+}
+
+
+const ComparisonBinaryOperator kComparisonBinaryOperators[] = {
+#define OPCODE(Opcode)                         \
+  { &MachineOperatorBuilder::Opcode, #Opcode } \
+  ,
+    MACHINE_COMPARE_BINOP_LIST(OPCODE)
+#undef OPCODE
+};
+
 }  // namespace
 
 
 // -----------------------------------------------------------------------------
 // Unary operators
 
 
 namespace {
 
 struct UnaryOperator {
@@ skipping 379 matching lines @@
           Int32Constant(-1 << l)));
       ASSERT_TRUE(r2.Changed());
       EXPECT_THAT(r2.replacement(),
                   IsInt32Add(IsWord32And(p0, IsInt32Constant(-1 << l)),
                              IsInt32Mul(p1, IsInt32Constant(k << l))));
     }
   }
 }
 
 
+TEST_F(MachineOperatorReducerTest, Word32AndWithComparisonAndConstantOne) {
+  Node* const p0 = Parameter(0);
+  Node* const p1 = Parameter(1);
+  TRACED_FOREACH(ComparisonBinaryOperator, cbop, kComparisonBinaryOperators) {
+    Node* cmp = graph()->NewNode((machine()->*cbop.constructor)(), p0, p1);
+
+    // cmp & 1 => cmp
+    Reduction const r1 =
+        Reduce(graph()->NewNode(machine()->Word32And(), cmp, Int32Constant(1)));
+    ASSERT_TRUE(r1.Changed());
+    EXPECT_EQ(cmp, r1.replacement());
+
+    // 1 & cmp => cmp
+    Reduction const r2 =
+        Reduce(graph()->NewNode(machine()->Word32And(), Int32Constant(1), cmp));
+    ASSERT_TRUE(r2.Changed());
+    EXPECT_EQ(cmp, r2.replacement());
+  }
+}
+
+
 // -----------------------------------------------------------------------------
 // Word32Xor
 
 
 TEST_F(MachineOperatorReducerTest, Word32XorWithWord32XorAndMinusOne) {
   Node* const p0 = Parameter(0);
 
   // (x ^ -1) ^ -1 => x
   Reduction r1 = Reduce(graph()->NewNode(
       machine()->Word32Xor(),
@@ skipping 121 matching lines @@
                   IsInt32Constant(base::bits::RotateRight32(x, y)));
     }
   }
 }
 
 
 // -----------------------------------------------------------------------------
 // Word32Sar
 
 
+TEST_F(MachineOperatorReducerTest, Word32SarWithWord32ShlAndComparison) {
+  Node* const p0 = Parameter(0);
+  Node* const p1 = Parameter(1);
+
+  TRACED_FOREACH(ComparisonBinaryOperator, cbop, kComparisonBinaryOperators) {
+    Node* cmp = graph()->NewNode((machine()->*cbop.constructor)(), p0, p1);
+
+    // cmp << 31 >> 31 => 0 - cmp
+    Reduction const r = Reduce(graph()->NewNode(
+        machine()->Word32Sar(),
+        graph()->NewNode(machine()->Word32Shl(), cmp, Int32Constant(31)),
+        Int32Constant(31)));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(r.replacement(), IsInt32Sub(IsInt32Constant(0), cmp));
+  }
+}
+
+
 TEST_F(MachineOperatorReducerTest, Word32SarWithWord32ShlAndLoad) {
   Node* const p0 = Parameter(0);
   Node* const p1 = Parameter(1);
   {
     Node* const l = graph()->NewNode(machine()->Load(kMachInt8), p0, p1,
                                      graph()->start(), graph()->start());
     Reduction const r = Reduce(graph()->NewNode(
         machine()->Word32Sar(),
         graph()->NewNode(machine()->Word32Shl(), l, Int32Constant(24)),
         Int32Constant(24)));
@@ skipping 397 matching lines @@
 TEST_F(MachineOperatorReducerTest, Uint32ModWithParameters) {
   Node* const p0 = Parameter(0);
   Reduction const r = Reduce(
       graph()->NewNode(machine()->Uint32Mod(), p0, p0, graph()->start()));
   ASSERT_TRUE(r.Changed());
   EXPECT_THAT(r.replacement(), IsInt32Constant(0));
 }
 
 
 // -----------------------------------------------------------------------------
+// Int32Add
+
+
+TEST_F(MachineOperatorReducerTest, Int32AddWithInt32SubWithConstantZero) {
+  Node* const p0 = Parameter(0);
+  Node* const p1 = Parameter(1);
+
+  Reduction const r1 = Reduce(graph()->NewNode(
+      machine()->Int32Add(),
+      graph()->NewNode(machine()->Int32Sub(), Int32Constant(0), p0), p1));
+  ASSERT_TRUE(r1.Changed());
+  EXPECT_THAT(r1.replacement(), IsInt32Sub(p1, p0));
+
+  Reduction const r2 = Reduce(graph()->NewNode(
+      machine()->Int32Add(), p0,
+      graph()->NewNode(machine()->Int32Sub(), Int32Constant(0), p1)));
+  ASSERT_TRUE(r2.Changed());
+  EXPECT_THAT(r2.replacement(), IsInt32Sub(p0, p1));
+}
+
+
+// -----------------------------------------------------------------------------
 // Int32AddWithOverflow
 
 
 TEST_F(MachineOperatorReducerTest, Int32AddWithOverflowWithZero) {
   Node* p0 = Parameter(0);
   {
     Node* add = graph()->NewNode(machine()->Int32AddWithOverflow(),
                                  Int32Constant(0), p0);
 
     Reduction r = Reduce(graph()->NewNode(common()->Projection(1), add));
@@ skipping 214 matching lines @@
     Reduction r = Reduce(node);
     ASSERT_TRUE(r.Changed());
     EXPECT_THAT(r.replacement(),
                 IsStore(rep, base, index, value, effect, control));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8