[Turbofan]: Add integer multiplication with overflow to typed lowering.

src/compiler/simplified-lowering.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/compiler/simplified-lowering.h"
 
 #include <limits>
 
 #include "src/address-map.h"
 #include "src/base/bits.h"
@@ skipping 1295 matching lines @@
           // => signed Int32Add/Sub (truncated)
           VisitWord32TruncatingBinop(node);
           if (lower()) NodeProperties::ChangeOp(node, Int32Op(node));
         } else {
           // => Float64Add/Sub
           VisitFloat64Binop(node);
           if (lower()) NodeProperties::ChangeOp(node, Float64Op(node));
         }
         return;
       }
-      case IrOpcode::kSpeculativeNumberMultiply:
-      case IrOpcode::kNumberMultiply: {
+      case IrOpcode::kSpeculativeNumberMultiply: {
         if (BothInputsAre(node, Type::Integral32()) &&
             (NodeProperties::GetType(node)->Is(Type::Signed32()) ||
              NodeProperties::GetType(node)->Is(Type::Unsigned32()) ||
              (truncation.TruncatesToWord32() &&
               NodeProperties::GetType(node)->Is(
                   type_cache_.kSafeIntegerOrMinusZero)))) {
           // Multiply reduces to Int32Mul if the inputs are integers, and
           // (a) the output is either known to be Signed32, or
           // (b) the output is known to be Unsigned32, or
           // (c) the uses are truncating and the result is in the safe
           //     integer range.
           VisitWord32TruncatingBinop(node);
           if (lower()) ChangeToPureOp(node, Int32Op(node));
           return;
         }
+        // Try to use type feedback.
+        BinaryOperationHints::Hint hint = BinaryOperationHintOf(node->op());
+
+        // Handle the case when no int32 checks on inputs are necessary
+        // (but an overflow check is needed on the output).
+        if (BothInputsAre(node, Type::Signed32())) {
+          // If both the inputs the feedback are int32, use the overflow op.
+          if (hint == BinaryOperationHints::kSignedSmall ||
+              hint == BinaryOperationHints::kSigned32) {
+            VisitBinop(node, UseInfo::TruncatingWord32(),
+                       MachineRepresentation::kWord32, Type::Signed32());
+            if (lower()) ChangeToInt32OverflowOp(node);
+            return;
+          }
+        }
+
+        if (hint == BinaryOperationHints::kSignedSmall ||
+            hint == BinaryOperationHints::kSigned32) {
+          // If the result is truncated, we only need to check the inputs.

[Benedikt Meurer, 2016/07/14 12:08:22]

Also as discussed offline, this code is wrong, please remove it (the truncation
case).

+          if (truncation.TruncatesToWord32()) {
+            VisitBinop(node, UseInfo::CheckedSigned32AsWord32(),
+                       MachineRepresentation::kWord32);
+            if (lower()) ChangeToPureOp(node, Int32Op(node));
+          } else {
+            VisitBinop(node, UseInfo::CheckedSigned32AsWord32(),
+                       MachineRepresentation::kWord32, Type::Signed32());
+            if (lower()) ChangeToInt32OverflowOp(node);
+          }
+          return;
+        }
+
         // Number x Number => Float64Mul
-        if (BothInputsAre(node, Type::NumberOrUndefined())) {
+        if (BothInputsAre(node, Type::Number())) {

[Benedikt Meurer, 2016/07/14 11:43:00]

This whole if block is redundant. Drop it as well.

           VisitFloat64Binop(node);
           if (lower()) ChangeToPureOp(node, Float64Op(node));
           return;
         }
         // Checked float64 x float64 => float64
-        DCHECK_EQ(IrOpcode::kSpeculativeNumberMultiply, node->opcode());
         VisitBinop(node, UseInfo::CheckedNumberOrOddballAsFloat64(),
                    MachineRepresentation::kFloat64, Type::Number());
         if (lower()) ChangeToPureOp(node, Float64Op(node));
         return;
       }
+      case IrOpcode::kNumberMultiply: {
+        if (BothInputsAre(node, Type::Integral32()) &&
+            (NodeProperties::GetType(node)->Is(Type::Signed32()) ||
+             NodeProperties::GetType(node)->Is(Type::Unsigned32()) ||
+             (truncation.TruncatesToWord32() &&
+              NodeProperties::GetType(node)->Is(
+                  type_cache_.kSafeIntegerOrMinusZero)))) {
+          // Multiply reduces to Int32Mul if the inputs are integers, and
+          // (a) the output is either known to be Signed32, or
+          // (b) the output is known to be Unsigned32, or
+          // (c) the uses are truncating and the result is in the safe
+          //     integer range.
+          VisitWord32TruncatingBinop(node);
+          if (lower()) ChangeToPureOp(node, Int32Op(node));
+          return;
+        }
+        // Number x Number => Float64Mul
+        VisitFloat64Binop(node);
+        if (lower()) ChangeToPureOp(node, Float64Op(node));
+        return;
+      }
       case IrOpcode::kSpeculativeNumberDivide: {
         if (BothInputsAreUnsigned32(node) && truncation.TruncatesToWord32()) {
           // => unsigned Uint32Div
           VisitWord32TruncatingBinop(node);
           if (lower()) DeferReplacement(node, lowering->Uint32Div(node));
           return;
         }
         if (BothInputsAreSigned32(node)) {
           if (NodeProperties::GetType(node)->Is(Type::Signed32())) {
           // => signed Int32Div
@@ skipping 1913 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kNoProperties);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8