[Turbofan] Add concept of FP register aliasing on ARM 32.

test/unittests/compiler/instruction-unittest.cc

+// Copyright 2016 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/compiler/instruction.h"
+#include "src/register-configuration.h"
+#include "test/unittests/test-utils.h"
+#include "testing/gtest-support.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+namespace {
+
+const MachineRepresentation kWord = MachineRepresentation::kWord32;
+const MachineRepresentation kFloat = MachineRepresentation::kFloat32;
+const MachineRepresentation kDouble = MachineRepresentation::kFloat64;
+
+bool Interfere(LocationOperand::LocationKind kind, MachineRepresentation rep1,
+               int index1, MachineRepresentation rep2, int index2) {
+  return AllocatedOperand(kind, rep1, index1)
+      .InterferesWith(AllocatedOperand(kind, rep2, index2));
+}
+
+bool Contains(const ZoneVector<MoveOperands*>* moves,
+              const InstructionOperand& to, const InstructionOperand& from) {
+  for (auto move : *moves) {
+    if (move->destination().Equals(to) && move->source().Equals(from)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace
+
+class InstructionTest : public TestWithZone {
+ public:
+  InstructionTest() {}
+  virtual ~InstructionTest() {}
+
+  ParallelMove* CreateParallelMove(
+      const std::vector<InstructionOperand>& operand_pairs) {
+    ParallelMove* parallel_move = new (zone()) ParallelMove(zone());
+    for (size_t i = 0; i < operand_pairs.size(); i += 2)
+      parallel_move->AddMove(operand_pairs[i + 1], operand_pairs[i]);
+    return parallel_move;
+  }
+};
+
+TEST_F(InstructionTest, OperandInterference) {
+  // All general registers and slots interfere only with themselves.
+  for (int i = 0; i < RegisterConfiguration::kMaxGeneralRegisters; ++i) {
+    EXPECT_TRUE(Interfere(LocationOperand::REGISTER, kWord, i, kWord, i));
+    EXPECT_TRUE(Interfere(LocationOperand::STACK_SLOT, kWord, i, kWord, i));
+    for (int j = i + 1; j < RegisterConfiguration::kMaxGeneralRegisters; ++j) {
+      EXPECT_FALSE(Interfere(LocationOperand::REGISTER, kWord, i, kWord, j));
+      EXPECT_FALSE(Interfere(LocationOperand::STACK_SLOT, kWord, i, kWord, j));
+    }
+  }
+
+  // All FP registers interfere with themselves.
+  for (int i = 0; i < RegisterConfiguration::kMaxFPRegisters; ++i) {
+    EXPECT_TRUE(Interfere(LocationOperand::REGISTER, kFloat, i, kFloat, i));
+    EXPECT_TRUE(Interfere(LocationOperand::STACK_SLOT, kFloat, i, kFloat, i));
+    EXPECT_TRUE(Interfere(LocationOperand::REGISTER, kDouble, i, kDouble, i));
+    EXPECT_TRUE(Interfere(LocationOperand::STACK_SLOT, kDouble, i, kDouble, i));
+  }
+
+  if (kSimpleFPAliasing) {
+    // Simple FP aliasing: interfering registers of different reps have the same
+    // index.
+    for (int i = 0; i < RegisterConfiguration::kMaxFPRegisters; ++i) {
+      EXPECT_TRUE(Interfere(LocationOperand::REGISTER, kFloat, i, kDouble, i));
+      EXPECT_TRUE(Interfere(LocationOperand::REGISTER, kDouble, i, kFloat, i));
+      for (int j = i + 1; j < RegisterConfiguration::kMaxFPRegisters; ++j) {
+        EXPECT_FALSE(Interfere(LocationOperand::REGISTER, kWord, i, kWord, j));
+        EXPECT_FALSE(
+            Interfere(LocationOperand::STACK_SLOT, kWord, i, kWord, j));
+      }
+    }
+  } else {
+    // Complex FP aliasing: sub-registers intefere with containing registers.
+    // Test sub-register indices which may not exist on the platform. This is
+    // necessary since the GapResolver may split large moves into smaller ones.
+    for (int i = 0; i < RegisterConfiguration::kMaxFPRegisters; ++i) {
+      EXPECT_TRUE(
+          Interfere(LocationOperand::REGISTER, kFloat, i * 2, kDouble, i));
+      EXPECT_TRUE(
+          Interfere(LocationOperand::REGISTER, kFloat, i * 2 + 1, kDouble, i));
+      EXPECT_TRUE(
+          Interfere(LocationOperand::REGISTER, kDouble, i, kFloat, i * 2));
+      EXPECT_TRUE(
+          Interfere(LocationOperand::REGISTER, kDouble, i, kFloat, i * 2 + 1));
+
+      for (int j = i + 1; j < RegisterConfiguration::kMaxFPRegisters; ++j) {
+        EXPECT_FALSE(
+            Interfere(LocationOperand::REGISTER, kFloat, i * 2, kDouble, j));
+        EXPECT_FALSE(Interfere(LocationOperand::REGISTER, kFloat, i * 2 + 1,
+                               kDouble, j));
+        EXPECT_FALSE(
+            Interfere(LocationOperand::REGISTER, kDouble, i, kFloat, j * 2));
+        EXPECT_FALSE(Interfere(LocationOperand::REGISTER, kDouble, i, kFloat,
+                               j * 2 + 1));
+      }
+    }
+  }
+}
+
+TEST_F(InstructionTest, PrepareInsertAfter) {
+  InstructionOperand r0 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kWord32, 0);
+  InstructionOperand r1 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kWord32, 1);
+  InstructionOperand r2 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kWord32, 2);
+
+  InstructionOperand d0 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kFloat64, 0);
+  InstructionOperand d1 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kFloat64, 1);
+  InstructionOperand d2 = AllocatedOperand(LocationOperand::REGISTER,
+                                           MachineRepresentation::kFloat64, 2);
+
+  {
+    // Moves inserted after should pick up assignments to their sources.
+    // Moves inserted after should cause interfering moves to be eliminated.
+    ZoneVector<MoveOperands*> to_eliminate(zone());
+    std::vector<InstructionOperand> moves = {
+        r1, r0,  // r1 <- r0
+        r2, r0,  // r2 <- r0
+        d1, d0,  // d1 <- d0
+        d2, d0   // d2 <- d0
+    };
+
+    ParallelMove* pm = CreateParallelMove(moves);
+    MoveOperands m1(r1, r2);  // r2 <- r1
+    pm->PrepareInsertAfter(&m1, &to_eliminate);
+    CHECK(m1.source().Equals(r0));
+    CHECK(Contains(&to_eliminate, r2, r0));
+    MoveOperands m2(d1, d2);  // d2 <- d1
+    pm->PrepareInsertAfter(&m2, &to_eliminate);
+    CHECK(m2.source().Equals(d0));
+    CHECK(Contains(&to_eliminate, d2, d0));
+  }
+
+  if (!kSimpleFPAliasing) {
+    // Moves inserted after should cause all interfering moves to be eliminated.
+    auto s0 = AllocatedOperand(LocationOperand::REGISTER,
+                               MachineRepresentation::kFloat32, 0);
+    auto s1 = AllocatedOperand(LocationOperand::REGISTER,
+                               MachineRepresentation::kFloat32, 1);
+    auto s2 = AllocatedOperand(LocationOperand::REGISTER,
+                               MachineRepresentation::kFloat32, 2);
+
+    {
+      ZoneVector<MoveOperands*> to_eliminate(zone());
+      std::vector<InstructionOperand> moves = {
+          s0, s2,  // s0 <- s2
+          s1, s2   // s1 <- s2
+      };
+
+      ParallelMove* pm = CreateParallelMove(moves);
+      MoveOperands m1(d1, d0);  // d0 <- d1
+      pm->PrepareInsertAfter(&m1, &to_eliminate);
+      CHECK(Contains(&to_eliminate, s0, s2));
+      CHECK(Contains(&to_eliminate, s1, s2));
+    }
+  }
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8