[arm64] Use ubfiz in ARM64 instruction selector

Select ubfiz for (x & mask) << imm where mask is contiguous and imm is non-zero.

BUG=

Review URL: https://codereview.chromium.org/1161643003

Cr-Commit-Position: refs/heads/master@{#28755}

src/compiler/arm64/code-generator-arm64.cc

@@ -654,6 +654,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ Ubfx(i.OutputRegister32(), i.InputRegister32(0), i.InputInt5(1),
               i.InputInt5(2));
       break;
+    case kArm64Ubfiz32:
+      __ Ubfiz(i.OutputRegister32(), i.InputRegister32(0), i.InputInt5(1),
+               i.InputInt5(2));
+      break;
     case kArm64Bfi:
       __ Bfi(i.OutputRegister(), i.InputRegister(1), i.InputInt6(2),
              i.InputInt6(3));

src/compiler/arm64/instruction-codes-arm64.h

@@ -72,6 +72,7 @@ namespace compiler {
   V(Arm64Sbfx32)                   \
   V(Arm64Ubfx)                     \
   V(Arm64Ubfx32)                   \
+  V(Arm64Ubfiz32)                  \
   V(Arm64Bfi)                      \
   V(Arm64TestAndBranch32)          \
   V(Arm64TestAndBranch)            \

src/compiler/arm64/instruction-selector-arm64.cc

@@ -641,6 +641,38 @@ void InstructionSelector::VisitWord64Xor(Node* node) {
 
 
 void InstructionSelector::VisitWord32Shl(Node* node) {
+  Int32BinopMatcher m(node);
+  if (m.left().IsWord32And() && CanCover(node, m.left().node()) &&
+      m.right().IsInRange(1, 31)) {
+    Arm64OperandGenerator g(this);
+    Int32BinopMatcher mleft(m.left().node());
+    if (mleft.right().HasValue()) {
+      uint32_t mask = mleft.right().Value();
+      uint32_t mask_width = base::bits::CountPopulation32(mask);
+      uint32_t mask_msb = base::bits::CountLeadingZeros32(mask);
+      if ((mask_width != 0) && (mask_msb + mask_width == 32)) {
+        uint32_t shift = m.right().Value();
+        DCHECK_EQ(0u, base::bits::CountTrailingZeros32(mask));
+        DCHECK_NE(0u, shift);
+
+        if ((shift + mask_width) >= 32) {
+          // If the mask is contiguous and reaches or extends beyond the top
+          // bit, only the shift is needed.
+          Emit(kArm64Lsl32, g.DefineAsRegister(node),
+               g.UseRegister(mleft.left().node()),
+               g.UseImmediate(m.right().node()));
+          return;
+        } else {
+          // Select Ubfiz for Shl(And(x, mask), imm) where the mask is
+          // contiguous, and the shift immediate non-zero.
+          Emit(kArm64Ubfiz32, g.DefineAsRegister(node),
+               g.UseRegister(mleft.left().node()),
+               g.UseImmediate(m.right().node()), g.TempImmediate(mask_width));
+          return;
+        }
+      }
+    }
+  }
   VisitRRO(this, kArm64Lsl32, node, kShift32Imm);
 }
 

test/unittests/compiler/arm64/instruction-selector-arm64-unittest.cc

@@ -2429,6 +2429,40 @@ TEST_F(InstructionSelectorTest, Word32ShrWithWord32Shl) {
 }
 
 
+TEST_F(InstructionSelectorTest, Word32ShlWithWord32And) {
+  TRACED_FORRANGE(int32_t, shift, 1, 30) {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const r =
+        m.Word32Shl(m.Word32And(p0, m.Int32Constant((1 << (31 - shift)) - 1)),
+                    m.Int32Constant(shift));
+    m.Return(r);
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Ubfiz32, s[0]->arch_opcode());
+    ASSERT_EQ(3U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->Output()));
+  }
+  TRACED_FORRANGE(int32_t, shift, 0, 30) {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const r =
+        m.Word32Shl(m.Word32And(p0, m.Int32Constant((1 << (31 - shift)) - 1)),
+                    m.Int32Constant(shift + 1));
+    m.Return(r);
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Lsl32, s[0]->arch_opcode());
+    ASSERT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->Output()));
+  }
+}
+
+
 TEST_F(InstructionSelectorTest, Word32Clz) {
   StreamBuilder m(this, kMachUint32, kMachUint32);
   Node* const p0 = m.Parameter(0);