[turbofan] Turn various diamonds into selects.

TEST=cctest/test-changes-lowering,mjsunit/asm,unittests
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/704463004

Cr-Commit-Position: refs/heads/master@{#25180}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25180 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/compiler/change-lowering.cc

@@ -102,10 +102,9 @@ Node* ChangeLowering::LoadHeapNumberValue(Node* value, Node* control) {
 
 
 Reduction ChangeLowering::ChangeBitToBool(Node* val, Node* control) {
-  Diamond d(graph(), common(), val);
-  d.Chain(control);
-  MachineType machine_type = static_cast<MachineType>(kTypeBool | kRepTagged);
-  return Replace(d.Phi(machine_type, jsgraph()->TrueConstant(),
+  MachineType const type = static_cast<MachineType>(kTypeBool | kRepTagged);
+  return Replace(graph()->NewNode(common()->Select(type), val,
+                                  jsgraph()->TrueConstant(),
                                   jsgraph()->FalseConstant()));
 }
 

src/compiler/js-builtin-reducer.cc

@@ -105,12 +105,12 @@ Reduction JSBuiltinReducer::ReduceMathAbs(Node* node) {
   }
   if (r.InputsMatchOne(Type::Number())) {
     // Math.abs(a:number) -> (a > 0 ? a : 0 - a)
-    Node* value = r.left();
-    Node* zero = jsgraph()->ZeroConstant();
-    Node* cmp = graph()->NewNode(simplified()->NumberLessThan(), zero, value);
-    Diamond d(graph(), common(), cmp);
-    Node* neg = graph()->NewNode(simplified()->NumberSubtract(), zero, value);
-    return Replace(d.Phi(kMachNone, value, neg));
+    Node* const value = r.left();
+    Node* const zero = jsgraph()->ZeroConstant();
+    return Replace(graph()->NewNode(
+        common()->Select(kMachNone),
+        graph()->NewNode(simplified()->NumberLessThan(), zero, value), value,
+        graph()->NewNode(simplified()->NumberSubtract(), zero, value)));
   }
   return NoChange();
 }
@@ -143,10 +143,11 @@ Reduction JSBuiltinReducer::ReduceMathMax(Node* node) {
     // Math.max(a:int32, b:int32, ...)
     Node* value = r.GetJSCallInput(0);
     for (int i = 1; i < r.GetJSCallArity(); i++) {
-      Node* p = r.GetJSCallInput(i);
-      Node* cmp = graph()->NewNode(simplified()->NumberLessThan(), value, p);
-      Diamond d(graph(), common(), cmp);
-      value = d.Phi(kMachNone, p, value);
+      Node* const input = r.GetJSCallInput(i);
+      value = graph()->NewNode(
+          common()->Select(kMachNone),
+          graph()->NewNode(simplified()->NumberLessThan(), input, value), input,
+          value);
     }
     return Replace(value);
   }

src/compiler/machine-operator-reducer.cc

@@ -644,13 +644,12 @@ Reduction MachineOperatorReducer::ReduceInt32Mod(Node* node) {
     if (base::bits::IsPowerOfTwo32(divisor)) {
       uint32_t const mask = divisor - 1;
       Node* const zero = Int32Constant(0);
-
-      Node* check =
-          graph()->NewNode(machine()->Int32LessThan(), dividend, zero);
-      Diamond d(graph(), common(), check, BranchHint::kFalse);
-      Node* neg = Int32Sub(zero, Word32And(Int32Sub(zero, dividend), mask));
-      Node* pos = Word32And(dividend, mask);
-      d.OverwriteWithPhi(node, kMachInt32, neg, pos);
+      node->set_op(common()->Select(kMachInt32, BranchHint::kFalse));
+      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));
     } else {
       Node* quotient = Int32Div(dividend, divisor);
       node->set_op(machine()->Int32Sub());

test/cctest/compiler/test-changes-lowering.cc

@@ -10,6 +10,7 @@
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/pipeline.h"
+#include "src/compiler/select-lowering.h"
 #include "src/compiler/simplified-lowering.h"
 #include "src/compiler/verifier.h"
 #include "src/execution.h"
@@ -126,9 +127,11 @@ class ChangesLoweringTester : public GraphBuilderTester<ReturnType> {
     // Run the graph reducer with changes lowering on a single node.
     CompilationInfo info(this->isolate(), this->zone());
     Linkage linkage(this->zone(), &info);
-    ChangeLowering lowering(&jsgraph, &linkage);
+    ChangeLowering change_lowering(&jsgraph, &linkage);
+    SelectLowering select_lowering(this->graph(), this->common());
     GraphReducer reducer(this->graph());
-    reducer.AddReducer(&lowering);
+    reducer.AddReducer(&change_lowering);
+    reducer.AddReducer(&select_lowering);
     reducer.ReduceNode(change);
     Verifier::Run(this->graph(), Verifier::UNTYPED);
   }

test/unittests/compiler/change-lowering-unittest.cc

@@ -124,15 +124,9 @@ TARGET_TEST_P(ChangeLoweringCommonTest, ChangeBitToBool) {
   Node* node = graph()->NewNode(simplified()->ChangeBitToBool(), val);
   Reduction reduction = Reduce(node);
   ASSERT_TRUE(reduction.Changed());
-
-  Node* phi = reduction.replacement();
-  Capture<Node*> branch;
-  EXPECT_THAT(phi,
-              IsPhi(static_cast<MachineType>(kTypeBool | kRepTagged),
-                    IsTrueConstant(), IsFalseConstant(),
-                    IsMerge(IsIfTrue(AllOf(CaptureEq(&branch),
-                                           IsBranch(val, graph()->start()))),
-                            IsIfFalse(CaptureEq(&branch)))));
+  EXPECT_THAT(reduction.replacement(),
+              IsSelect(static_cast<MachineType>(kTypeBool | kRepTagged), val,
+                       IsTrueConstant(), IsFalseConstant()));
 }
 
 

test/unittests/compiler/js-builtin-reducer-unittest.cc

@@ -88,14 +88,9 @@ TEST_F(JSBuiltinReducerTest, MathAbs) {
     } else {
       Capture<Node*> branch;
       ASSERT_TRUE(r.Changed());
-      EXPECT_THAT(
-          r.replacement(),
-          IsPhi(kMachNone, p0, IsNumberSubtract(IsNumberConstant(0), p0),
-                IsMerge(IsIfTrue(CaptureEq(&branch)),
-                        IsIfFalse(AllOf(
-                            CaptureEq(&branch),
-                            IsBranch(IsNumberLessThan(IsNumberConstant(0), p0),
-                                     graph()->start()))))));
+      EXPECT_THAT(r.replacement(),
+                  IsSelect(kMachNone, IsNumberLessThan(IsNumberConstant(0), p0),
+                           p0, IsNumberSubtract(IsNumberConstant(0), p0)));
     }
   }
 }
@@ -171,15 +166,9 @@ TEST_F(JSBuiltinReducerTest, MathMax2) {
       Reduction r = Reduce(call);
 
       if (t0->Is(Type::Integral32()) && t1->Is(Type::Integral32())) {
-        Capture<Node*> branch;
         ASSERT_TRUE(r.Changed());
-        EXPECT_THAT(
-            r.replacement(),
-            IsPhi(kMachNone, p1, p0,
-                  IsMerge(IsIfTrue(CaptureEq(&branch)),
-                          IsIfFalse(AllOf(CaptureEq(&branch),
-                                          IsBranch(IsNumberLessThan(p0, p1),
-                                                   graph()->start()))))));
+        EXPECT_THAT(r.replacement(),
+                    IsSelect(kMachNone, IsNumberLessThan(p1, p0), p1, p0));
       } else {
         ASSERT_FALSE(r.Changed());
         EXPECT_EQ(IrOpcode::kJSCallFunction, call->opcode());

test/unittests/compiler/machine-operator-reducer-unittest.cc

@@ -876,44 +876,30 @@ TEST_F(MachineOperatorReducerTest, Int32ModWithConstant) {
     Reduction const r =
         Reduce(graph()->NewNode(machine()->Int32Mod(), p0,
                                 Int32Constant(1 << shift), graph()->start()));
-    ASSERT_TRUE(r.Changed());
-
-    Capture<Node*> branch;
-    Node* const phi = r.replacement();
     int32_t const mask = (1 << shift) - 1;
+    ASSERT_TRUE(r.Changed());
     EXPECT_THAT(
-        phi, IsPhi(kMachInt32,
+        r.replacement(),
+        IsSelect(kMachInt32, IsInt32LessThan(p0, IsInt32Constant(0)),
                  IsInt32Sub(IsInt32Constant(0),
                             IsWord32And(IsInt32Sub(IsInt32Constant(0), p0),
                                         IsInt32Constant(mask))),
-                   IsWord32And(p0, IsInt32Constant(mask)),
-                   IsMerge(IsIfTrue(CaptureEq(&branch)),
-                           IsIfFalse(AllOf(
-                               CaptureEq(&branch),
-                               IsBranch(IsInt32LessThan(p0, IsInt32Constant(0)),
-                                        graph()->start()))))));
+                 IsWord32And(p0, IsInt32Constant(mask))));
   }
   TRACED_FORRANGE(int32_t, shift, 1, 31) {
     Reduction const r = Reduce(graph()->NewNode(
         machine()->Int32Mod(), p0,
         Uint32Constant(bit_cast<uint32_t, int32_t>(-1) << shift),
         graph()->start()));
-    ASSERT_TRUE(r.Changed());
-
-    Capture<Node*> branch;
-    Node* const phi = r.replacement();
     int32_t const mask = bit_cast<int32_t, uint32_t>((1U << shift) - 1);
+    ASSERT_TRUE(r.Changed());
     EXPECT_THAT(
-        phi, IsPhi(kMachInt32,
+        r.replacement(),
+        IsSelect(kMachInt32, IsInt32LessThan(p0, IsInt32Constant(0)),
                  IsInt32Sub(IsInt32Constant(0),
                             IsWord32And(IsInt32Sub(IsInt32Constant(0), p0),
                                         IsInt32Constant(mask))),
-                   IsWord32And(p0, IsInt32Constant(mask)),
-                   IsMerge(IsIfTrue(CaptureEq(&branch)),
-                           IsIfFalse(AllOf(
-                               CaptureEq(&branch),
-                               IsBranch(IsInt32LessThan(p0, IsInt32Constant(0)),
-                                        graph()->start()))))));
+                 IsWord32And(p0, IsInt32Constant(mask))));
   }
   TRACED_FOREACH(int32_t, divisor, kInt32Values) {
     if (divisor == 0 || base::bits::IsPowerOfTwo32(Abs(divisor))) continue;