[turbofan] Reduces x << y ^ x >>> (32 - y) to x ror (32 - y).

The MachineOperatorReducer was only reducing word32 expressions of the type x << y | x >>> (32 - y) (and variants) to the equivalent Word32Ror. This CL applies the same pattern-matching logic to Word32Xor.

BUG=

Review-Url: https://codereview.chromium.org/2199323003
Cr-Commit-Position: refs/heads/master@{#38284}

src/compiler/machine-operator-reducer.cc

@@ -150,21 +150,8 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
       return ReduceWord32And(node);
     case IrOpcode::kWord32Or:
       return ReduceWord32Or(node);
-    case IrOpcode::kWord32Xor: {
-      Int32BinopMatcher m(node);
-      if (m.right().Is(0)) return Replace(m.left().node());  // x ^ 0 => x
-      if (m.IsFoldable()) {                                  // K ^ K => K
-        return ReplaceInt32(m.left().Value() ^ m.right().Value());
-      }
-      if (m.LeftEqualsRight()) return ReplaceInt32(0);  // x ^ x => 0
-      if (m.left().IsWord32Xor() && m.right().Is(-1)) {
-        Int32BinopMatcher mleft(m.left().node());
-        if (mleft.right().Is(-1)) {  // (x ^ -1) ^ -1 => x
-          return Replace(mleft.left().node());
-        }
-      }
-      break;
-    }
+    case IrOpcode::kWord32Xor:
+      return ReduceWord32Xor(node);
     case IrOpcode::kWord32Shl:
       return ReduceWord32Shl(node);
     case IrOpcode::kWord32Shr:
@@ -1106,22 +1093,17 @@ Reduction MachineOperatorReducer::ReduceWord32And(Node* node) {
   return NoChange();
 }
 
-
-Reduction MachineOperatorReducer::ReduceWord32Or(Node* node) {
-  DCHECK_EQ(IrOpcode::kWord32Or, node->opcode());
+Reduction MachineOperatorReducer::TryMatchWord32Ror(Node* node) {
+  DCHECK(IrOpcode::kWord32Or == node->opcode() ||
+         IrOpcode::kWord32Xor == node->opcode());
   Int32BinopMatcher m(node);
-  if (m.right().Is(0)) return Replace(m.left().node());    // x | 0  => x
-  if (m.right().Is(-1)) return Replace(m.right().node());  // x | -1 => -1
-  if (m.IsFoldable()) {                                    // K | K  => K
-    return ReplaceInt32(m.left().Value() | m.right().Value());
-  }
-  if (m.LeftEqualsRight()) return Replace(m.left().node());  // x | x => x
-
   Node* shl = nullptr;
   Node* shr = nullptr;
-  // Recognize rotation, we are matching either:
+  // Recognize rotation, we are matching:
   //  * x << y | x >>> (32 - y) => x ror (32 - y), i.e  x rol y
   //  * x << (32 - y) | x >>> y => x ror y
+  //  * x << y ^ x >>> (32 - y) => x ror (32 - y), i.e. x rol y
+  //  * x << (32 - y) ^ x >>> y => x ror y
   // as well as their commuted form.
   if (m.left().IsWord32Shl() && m.right().IsWord32Shr()) {
     shl = m.left().node();
@@ -1163,6 +1145,36 @@ Reduction MachineOperatorReducer::ReduceWord32Or(Node* node) {
   return Changed(node);
 }
 
+Reduction MachineOperatorReducer::ReduceWord32Or(Node* node) {
+  DCHECK_EQ(IrOpcode::kWord32Or, node->opcode());
+  Int32BinopMatcher m(node);
+  if (m.right().Is(0)) return Replace(m.left().node());    // x | 0  => x
+  if (m.right().Is(-1)) return Replace(m.right().node());  // x | -1 => -1
+  if (m.IsFoldable()) {                                    // K | K  => K
+    return ReplaceInt32(m.left().Value() | m.right().Value());
+  }
+  if (m.LeftEqualsRight()) return Replace(m.left().node());  // x | x => x
+
+  return TryMatchWord32Ror(node);
+}
+
+Reduction MachineOperatorReducer::ReduceWord32Xor(Node* node) {
+  DCHECK_EQ(IrOpcode::kWord32Xor, node->opcode());
+  Int32BinopMatcher m(node);
+  if (m.right().Is(0)) return Replace(m.left().node());  // x ^ 0 => x
+  if (m.IsFoldable()) {                                  // K ^ K => K
+    return ReplaceInt32(m.left().Value() ^ m.right().Value());
+  }
+  if (m.LeftEqualsRight()) return ReplaceInt32(0);  // x ^ x => 0
+  if (m.left().IsWord32Xor() && m.right().Is(-1)) {
+    Int32BinopMatcher mleft(m.left().node());
+    if (mleft.right().Is(-1)) {  // (x ^ -1) ^ -1 => x
+      return Replace(mleft.left().node());
+    }
+  }
+
+  return TryMatchWord32Ror(node);
+}
 
 Reduction MachineOperatorReducer::ReduceFloat64InsertLowWord32(Node* node) {
   DCHECK_EQ(IrOpcode::kFloat64InsertLowWord32, node->opcode());

src/compiler/machine-operator-reducer.h

@@ -79,7 +79,9 @@ class MachineOperatorReducer final : public Reducer {
   Reduction ReduceWord32Shr(Node* node);
   Reduction ReduceWord32Sar(Node* node);
   Reduction ReduceWord32And(Node* node);
+  Reduction TryMatchWord32Ror(Node* node);
   Reduction ReduceWord32Or(Node* node);
+  Reduction ReduceWord32Xor(Node* node);
   Reduction ReduceFloat64InsertLowWord32(Node* node);
   Reduction ReduceFloat64InsertHighWord32(Node* node);
   Reduction ReduceFloat64Compare(Node* node);

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

@@ -729,25 +729,52 @@ TEST_F(MachineOperatorReducerTest, ReduceToWord32RorWithParameters) {
   EXPECT_EQ(reduction2.replacement(), node2);
   EXPECT_THAT(reduction2.replacement(), IsWord32Ror(value, sub));
 
-  // Testing rotate right.
-  Node* shl_r = graph()->NewNode(machine()->Word32Shl(), value, sub);
-  Node* shr_r = graph()->NewNode(machine()->Word32Shr(), value, shift);
-
-  // (x << (32 - y)) | (x >>> y) => x ror y
-  Node* node3 = graph()->NewNode(machine()->Word32Or(), shl_r, shr_r);
+  // (x << y) ^ (x >>> (32 - y)) => x ror (32 - y)
+  Node* node3 = graph()->NewNode(machine()->Word32Xor(), shl_l, shr_l);
   Reduction reduction3 = Reduce(node3);
   EXPECT_TRUE(reduction3.Changed());
   EXPECT_EQ(reduction3.replacement(), node3);
-  EXPECT_THAT(reduction3.replacement(), IsWord32Ror(value, shift));
+  EXPECT_THAT(reduction3.replacement(), IsWord32Ror(value, sub));
 
-  // (x >>> y) | (x << (32 - y)) => x ror y
-  Node* node4 = graph()->NewNode(machine()->Word32Or(), shr_r, shl_r);
+  // (x >>> (32 - y)) ^ (x << y) => x ror (32 - y)
+  Node* node4 = graph()->NewNode(machine()->Word32Xor(), shr_l, shl_l);
   Reduction reduction4 = Reduce(node4);
   EXPECT_TRUE(reduction4.Changed());
   EXPECT_EQ(reduction4.replacement(), node4);
-  EXPECT_THAT(reduction4.replacement(), IsWord32Ror(value, shift));
-}
+  EXPECT_THAT(reduction4.replacement(), IsWord32Ror(value, sub));
 
+  // Testing rotate right.
+  Node* shl_r = graph()->NewNode(machine()->Word32Shl(), value, sub);
+  Node* shr_r = graph()->NewNode(machine()->Word32Shr(), value, shift);
+
+  // (x << (32 - y)) | (x >>> y) => x ror y
+  Node* node5 = graph()->NewNode(machine()->Word32Or(), shl_r, shr_r);
+  Reduction reduction5 = Reduce(node5);
+  EXPECT_TRUE(reduction5.Changed());
+  EXPECT_EQ(reduction5.replacement(), node5);
+  EXPECT_THAT(reduction5.replacement(), IsWord32Ror(value, shift));
+
+  // (x >>> y) | (x << (32 - y)) => x ror y
+  Node* node6 = graph()->NewNode(machine()->Word32Or(), shr_r, shl_r);
+  Reduction reduction6 = Reduce(node6);
+  EXPECT_TRUE(reduction6.Changed());
+  EXPECT_EQ(reduction6.replacement(), node6);
+  EXPECT_THAT(reduction6.replacement(), IsWord32Ror(value, shift));
+
+  // (x << (32 - y)) ^ (x >>> y) => x ror y
+  Node* node7 = graph()->NewNode(machine()->Word32Xor(), shl_r, shr_r);
+  Reduction reduction7 = Reduce(node7);
+  EXPECT_TRUE(reduction7.Changed());
+  EXPECT_EQ(reduction7.replacement(), node7);
+  EXPECT_THAT(reduction7.replacement(), IsWord32Ror(value, shift));
+
+  // (x >>> y) ^ (x << (32 - y)) => x ror y
+  Node* node8 = graph()->NewNode(machine()->Word32Xor(), shr_r, shl_r);
+  Reduction reduction8 = Reduce(node8);
+  EXPECT_TRUE(reduction8.Changed());
+  EXPECT_EQ(reduction8.replacement(), node8);
+  EXPECT_THAT(reduction8.replacement(), IsWord32Ror(value, shift));
+}
 
 TEST_F(MachineOperatorReducerTest, ReduceToWord32RorWithConstant) {
   Node* value = Parameter(0);