Revert "Initial implementation of sparse conditional constant propagation."

runtime/lib/integers.cc

Index: runtime/lib/integers.cc
diff --git a/runtime/lib/integers.cc b/runtime/lib/integers.cc
index cde89cc64df04710ed1b652177ee3df0d1b80f63..498eac75b5b10a521baec39aaf44a808521e7bd8 100644
--- a/runtime/lib/integers.cc
+++ b/runtime/lib/integers.cc
@@ -17,6 +17,52 @@ DEFINE_FLAG(bool, trace_intrinsified_natives, false,
 
 // Smi natives.
 
+// Return the most compact presentation of an integer.
+static RawInteger* AsInteger(const Integer& value) {
+  if (value.IsSmi()) return value.raw();
+  if (value.IsMint()) {
+    Mint& mint = Mint::Handle();
+    mint ^= value.raw();
+    if (Smi::IsValid64(mint.value())) {
+      return Smi::New(mint.value());
+    } else {
+      return value.raw();
+    }
+  }
+  ASSERT(value.IsBigint());
+  Bigint& big_value = Bigint::Handle();
+  big_value ^= value.raw();
+  if (BigintOperations::FitsIntoSmi(big_value)) {
+    return BigintOperations::ToSmi(big_value);
+  } else if (BigintOperations::FitsIntoMint(big_value)) {
+    return Mint::New(BigintOperations::ToMint(big_value));
+  } else {
+    return big_value.raw();
+  }
+}
+
+
+// Returns value in form of a RawBigint.
+static RawBigint* AsBigint(const Integer& value) {
+  ASSERT(!value.IsNull());
+  if (value.IsSmi()) {
+    Smi& smi = Smi::Handle();
+    smi ^= value.raw();
+    return BigintOperations::NewFromSmi(smi);
+  } else if (value.IsMint()) {
+    Mint& mint = Mint::Handle();
+    mint ^= value.raw();
+    return BigintOperations::NewFromInt64(mint.value());
+  } else {
+    ASSERT(value.IsBigint());
+    Bigint& big = Bigint::Handle();
+    big ^= value.raw();
+    ASSERT(!BigintOperations::FitsIntoSmi(big));
+    return big.raw();
+  }
+}
+
+
 static bool Are64bitOperands(const Integer& op1, const Integer& op2) {
   return !op1.IsBigint() && !op2.IsBigint();
 }
@@ -60,8 +106,8 @@ static RawInteger* IntegerBitOperation(Token::Kind kind,
         UNIMPLEMENTED();
     }
   } else {
-    Bigint& op1 = Bigint::Handle(Bigint::AsBigint(op1_int));
-    Bigint& op2 = Bigint::Handle(Bigint::AsBigint(op2_int));
+    Bigint& op1 = Bigint::Handle(AsBigint(op1_int));
+    Bigint& op2 = Bigint::Handle(AsBigint(op2_int));
     switch (kind) {
       case Token::kBIT_AND:
         return BigintOperations::BitAnd(op1, op2);
@@ -106,7 +152,7 @@ DEFINE_NATIVE_ENTRY(Integer_bitAndFromInteger, 2) {
   }
   Integer& result = Integer::Handle(
       IntegerBitOperation(Token::kBIT_AND, left, right));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
 }
 
 
@@ -121,7 +167,7 @@ DEFINE_NATIVE_ENTRY(Integer_bitOrFromInteger, 2) {
   }
   Integer& result = Integer::Handle(
       IntegerBitOperation(Token::kBIT_OR, left, right));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
 }
 
 
@@ -136,7 +182,128 @@ DEFINE_NATIVE_ENTRY(Integer_bitXorFromInteger, 2) {
   }
   Integer& result = Integer::Handle(
       IntegerBitOperation(Token::kBIT_XOR, left, right));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
+}
+
+
+static RawBigint* BinaryOpWithTwoBigints(Token::Kind operation,
+                                         const Bigint& left,
+                                         const Bigint& right) {
+  switch (operation) {
+    case Token::kADD:
+      return BigintOperations::Add(left, right);
+    case Token::kSUB:
+      return BigintOperations::Subtract(left, right);
+    case Token::kMUL:
+      return BigintOperations::Multiply(left, right);
+    case Token::kTRUNCDIV:
+      return BigintOperations::Divide(left, right);
+    case Token::kMOD:
+      return BigintOperations::Modulo(left, right);
+    default:
+      UNIMPLEMENTED();
+      return Bigint::null();
+  }
+}
+
+
+static RawInteger* IntegerBinopHelper(Token::Kind operation,
+                                      const Integer& left_int,
+                                      const Integer& right_int) {
+  // In 32-bit mode, the result of any operation between two Smis will fit in a
+  // 32-bit signed result, except the product of two Smis, which will be 64-bit.
+  // In 64-bit mode, the result of any operation between two Smis will fit in a
+  // 64-bit signed result, except the product of two Smis (unless the Smis are
+  // 32-bit or less).
+  if (left_int.IsSmi() && right_int.IsSmi()) {
+    Smi& left_smi = Smi::Handle();
+    Smi& right_smi = Smi::Handle();
+    left_smi ^= left_int.raw();
+    right_smi ^= right_int.raw();
+    const intptr_t left_value = left_smi.Value();
+    const intptr_t right_value = right_smi.Value();
+    switch (operation) {
+      case Token::kADD:
+        return Integer::New(left_value + right_value);
+      case Token::kSUB:
+        return Integer::New(left_value - right_value);
+      case Token::kMUL: {
+        if (Smi::kBits < 32) {
+          // In 32-bit mode, the product of two Smis fits in a 64-bit result.
+          return Integer::New(static_cast<int64_t>(left_value) *
+                              static_cast<int64_t>(right_value));
+        } else {
+          // In 64-bit mode, the product of two 32-bit signed integers fits in a
+          // 64-bit result.
+          ASSERT(sizeof(intptr_t) == sizeof(int64_t));
+          if (Utils::IsInt(32, left_value) && Utils::IsInt(32, right_value)) {
+            return Integer::New(left_value * right_value);
+          }
+        }
+        // Perform a Bigint multiplication below.
+        break;
+      }
+      case Token::kTRUNCDIV:
+        return Integer::New(left_value / right_value);
+      case Token::kMOD: {
+        const intptr_t remainder = left_value % right_value;
+        if (remainder < 0) {
+          if (right_value < 0) {
+            return Integer::New(remainder - right_value);
+          } else {
+            return Integer::New(remainder + right_value);
+          }
+        }
+        return Integer::New(remainder);
+      }
+      default:
+        UNIMPLEMENTED();
+    }
+  }
+  // In 32-bit mode, the result of any operation between two 63-bit signed
+  // integers (or 32-bit for multiplication) will fit in a 64-bit signed result.
+  // In 64-bit mode, 63-bit signed integers are Smis, already processed above.
+  if ((Smi::kBits < 32) && !left_int.IsBigint() && !right_int.IsBigint()) {
+    const int64_t left_value = left_int.AsInt64Value();
+    if (Utils::IsInt(63, left_value)) {
+      const int64_t right_value = right_int.AsInt64Value();
+      if (Utils::IsInt(63, right_value)) {
+        switch (operation) {
+        case Token::kADD:
+          return Integer::New(left_value + right_value);
+        case Token::kSUB:
+          return Integer::New(left_value - right_value);
+        case Token::kMUL: {
+          if (Utils::IsInt(32, left_value) && Utils::IsInt(32, right_value)) {
+            return Integer::New(left_value * right_value);
+          }
+          // Perform a Bigint multiplication below.
+          break;
+        }
+        case Token::kTRUNCDIV:
+          return Integer::New(left_value / right_value);
+        case Token::kMOD: {
+          const int64_t remainder = left_value % right_value;
+          if (remainder < 0) {
+            if (right_value < 0) {
+              return Integer::New(remainder - right_value);
+            } else {
+              return Integer::New(remainder + right_value);
+            }
+          }
+          return Integer::New(remainder);
+        }
+        default:
+          UNIMPLEMENTED();
+        }
+      }
+    }
+  }
+  const Bigint& left_big = Bigint::Handle(AsBigint(left_int));
+  const Bigint& right_big = Bigint::Handle(AsBigint(right_int));
+  const Bigint& result =
+      Bigint::Handle(BinaryOpWithTwoBigints(operation, left_big, right_big));
+  return Integer::Handle(AsInteger(result)).raw();
 }
 
 
@@ -149,7 +316,7 @@ DEFINE_NATIVE_ENTRY(Integer_addFromInteger, 2) {
     OS::Print("Integer_addFromInteger %s + %s\n",
         left_int.ToCString(), right_int.ToCString());
   }
-  return Integer::BinaryOp(Token::kADD, left_int, right_int);
+  return IntegerBinopHelper(Token::kADD, left_int, right_int);
 }
 
 
@@ -162,7 +329,7 @@ DEFINE_NATIVE_ENTRY(Integer_subFromInteger, 2) {
     OS::Print("Integer_subFromInteger %s - %s\n",
         left_int.ToCString(), right_int.ToCString());
   }
-  return Integer::BinaryOp(Token::kSUB, left_int, right_int);
+  return IntegerBinopHelper(Token::kSUB, left_int, right_int);
 }
 
 
@@ -175,7 +342,7 @@ DEFINE_NATIVE_ENTRY(Integer_mulFromInteger, 2) {
     OS::Print("Integer_mulFromInteger %s * %s\n",
         left_int.ToCString(), right_int.ToCString());
   }
-  return Integer::BinaryOp(Token::kMUL, left_int, right_int);
+  return IntegerBinopHelper(Token::kMUL, left_int, right_int);
 }
 
 
@@ -185,7 +352,7 @@ DEFINE_NATIVE_ENTRY(Integer_truncDivFromInteger, 2) {
   ASSERT(CheckInteger(right_int));
   ASSERT(CheckInteger(left_int));
   ASSERT(!right_int.IsZero());
-  return Integer::BinaryOp(Token::kTRUNCDIV, left_int, right_int);
+  return IntegerBinopHelper(Token::kTRUNCDIV, left_int, right_int);
 }
 
 
@@ -202,7 +369,7 @@ DEFINE_NATIVE_ENTRY(Integer_moduloFromInteger, 2) {
     // Should have been caught before calling into runtime.
     UNIMPLEMENTED();
   }
-  return Integer::BinaryOp(Token::kMOD, left_int, right_int);
+  return IntegerBinopHelper(Token::kMOD, left_int, right_int);
 }
 
 
@@ -260,7 +427,7 @@ static RawInteger* SmiShiftOperation(Token::Kind kind,
         if ((cnt + right_value) >= Smi::kBits) {
           if ((cnt + right_value) >= Mint::kBits) {
             return BigintOperations::ShiftLeft(
-                Bigint::Handle(Bigint::AsBigint(left)), right_value);
+                Bigint::Handle(AsBigint(left)), right_value);
           } else {
             int64_t left_64 = left_value;
             return Integer::New(left_64 << right_value);
@@ -337,7 +504,7 @@ DEFINE_NATIVE_ENTRY(Smi_shrFromInt, 2) {
   ASSERT(CheckInteger(value));
   Integer& result = Integer::Handle(
       ShiftOperationHelper(Token::kSHR, value, amount));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
 }
 
 
@@ -353,7 +520,7 @@ DEFINE_NATIVE_ENTRY(Smi_shlFromInt, 2) {
   }
   Integer& result = Integer::Handle(
       ShiftOperationHelper(Token::kSHL, value, amount));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
 }
 
 
@@ -386,7 +553,7 @@ DEFINE_NATIVE_ENTRY(Bigint_bitNegate, 1) {
   const Bigint& result = Bigint::Handle(BigintOperations::BitNot(value));
   ASSERT(CheckInteger(value));
   ASSERT(CheckInteger(result));
-  return Integer::AsInteger(result);
+  return AsInteger(result);
 }
 
 }  // namespace dart