[wasm] Add a flag --wasm-opt to test optimizations in the WASM pipeline.

src/compiler/machine-operator-reducer.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/machine-operator-reducer.h"
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/base/ieee754.h"
 #include "src/codegen.h"
@@ skipping 32 matching lines @@
   return graph()->NewNode(common()->Int64Constant(value));
 }
 
 Node* MachineOperatorReducer::Float64Mul(Node* lhs, Node* rhs) {
   return graph()->NewNode(machine()->Float64Mul(), lhs, rhs);
 }
 
 Node* MachineOperatorReducer::Float64PowHalf(Node* value) {
   value =
       graph()->NewNode(machine()->Float64Add(), Float64Constant(0.0), value);
-  return graph()->NewNode(
-      common()->Select(MachineRepresentation::kFloat64, BranchHint::kFalse),
-      graph()->NewNode(machine()->Float64LessThanOrEqual(), value,
-                       Float64Constant(-V8_INFINITY)),
-      Float64Constant(V8_INFINITY),
-      graph()->NewNode(machine()->Float64Sqrt(), value));
+  Diamond d(graph(), common(),
+            graph()->NewNode(machine()->Float64LessThanOrEqual(), value,
+                             Float64Constant(-V8_INFINITY)),
+            BranchHint::kFalse);
+  return d.Phi(MachineRepresentation::kFloat64, Float64Constant(V8_INFINITY),
+               graph()->NewNode(machine()->Float64Sqrt(), value));
 }
 
 Node* MachineOperatorReducer::Word32And(Node* lhs, Node* rhs) {
   Node* const node = graph()->NewNode(machine()->Word32And(), lhs, rhs);
   Reduction const reduction = ReduceWord32And(node);
   return reduction.Changed() ? reduction.replacement() : node;
 }
 
 
 Node* MachineOperatorReducer::Word32Sar(Node* lhs, uint32_t rhs) {
@@ skipping 765 matching lines @@
   if (m.IsFoldable()) {                                   // K % K => K
     return ReplaceInt32(
         base::bits::SignedMod32(m.left().Value(), m.right().Value()));
   }
   if (m.right().HasValue()) {
     Node* const dividend = m.left().node();
     int32_t const divisor = Abs(m.right().Value());
     if (base::bits::IsPowerOfTwo32(divisor)) {
       uint32_t const mask = divisor - 1;
       Node* const zero = Int32Constant(0);
-      node->ReplaceInput(
-          0, graph()->NewNode(machine()->Int32LessThan(), dividend, zero));
-      node->ReplaceInput(
-          1, Int32Sub(zero, Word32And(Int32Sub(zero, dividend), mask)));
-      node->ReplaceInput(2, Word32And(dividend, mask));
-      NodeProperties::ChangeOp(
-          node,
-          common()->Select(MachineRepresentation::kWord32, BranchHint::kFalse));
+      Diamond d(graph(), common(),
+                graph()->NewNode(machine()->Int32LessThan(), dividend, zero),
+                BranchHint::kFalse);
+      return Replace(
+          d.Phi(MachineRepresentation::kWord32,
+                Int32Sub(zero, Word32And(Int32Sub(zero, dividend), mask)),
+                Word32And(dividend, mask)));
     } else {
       Node* quotient = Int32Div(dividend, divisor);
       DCHECK_EQ(dividend, node->InputAt(0));
       node->ReplaceInput(1, Int32Mul(quotient, Int32Constant(divisor)));
       node->TrimInputCount(2);
       NodeProperties::ChangeOp(node, machine()->Int32Sub());
     }
     return Changed(node);
   }
   return NoChange();
@@ skipping 539 matching lines @@
 MachineOperatorBuilder* MachineOperatorReducer::machine() const {
   return jsgraph()->machine();
 }
 
 
 Graph* MachineOperatorReducer::graph() const { return jsgraph()->graph(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8