[turbofan] Fix matching of the lea instruction.

Resets the scaled exponent to 0 when the scaling match fails.

BUG=

Review URL: https://codereview.chromium.org/756643002

Cr-Commit-Position: refs/heads/master@{#25491}

src/compiler/node-matchers.h

@@ -298,14 +298,16 @@ struct ScaledWithOffsetMatcher {
         Node* left_left = left_matcher.left().node();
         Node* left_right = left_matcher.right().node();
         if (left_matcher.HasScaledInput() && left_left->OwnedBy(left)) {
-          scaled_ = left_matcher.ScaledInput();
-          scale_exponent_ = left_matcher.ScaleExponent();
           if (left_matcher.right().HasValue()) {
             // ((S + C) + O)
+            scaled_ = left_matcher.ScaledInput();
+            scale_exponent_ = left_matcher.ScaleExponent();
             constant_ = left_right;
             offset_ = right;
           } else if (base_matcher.right().HasValue()) {
             // ((S + O) + C)
+            scaled_ = left_matcher.ScaledInput();
+            scale_exponent_ = left_matcher.ScaleExponent();
             offset_ = left_right;
             constant_ = right;
           } else {

test/mjsunit/regress/regress-lea-matching.js

+// 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.
+
+function f(a, b, c) {
+  a = a|0;
+  b = b|0;
+  c = c|0;
+  var r = 0;
+  r = a + ((b << 1) + c) | 0;
+  return r|0;
+}
+
+assertEquals(8, f(1, 2, 3));

test/unittests/compiler/x64/instruction-selector-x64-unittest.cc

@@ -741,6 +741,31 @@ TEST_F(InstructionSelectorTest, Int32SubConstantAsLea) {
 }
 
 
+TEST_F(InstructionSelectorTest, Int32AddScaled2Other) {
+  StreamBuilder m(this, kMachInt32, kMachInt32, kMachInt32, kMachInt32);
+  Node* const p0 = m.Parameter(0);
+  Node* const p1 = m.Parameter(1);
+  Node* const p2 = m.Parameter(2);
+  Node* const s0 = m.Int32Mul(p1, m.Int32Constant(2));
+  Node* const a0 = m.Int32Add(s0, p2);
+  Node* const a1 = m.Int32Add(p0, a0);
+  m.Return(a1);
+  Stream s = m.Build();
+  ASSERT_EQ(2U, s.size());
+  EXPECT_EQ(kX64Lea32, s[0]->arch_opcode());
+  EXPECT_EQ(kMode_MR2, s[0]->addressing_mode());
+  ASSERT_EQ(2U, s[0]->InputCount());
+  EXPECT_EQ(s.ToVreg(p2), s.ToVreg(s[0]->InputAt(0)));
+  EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
+  EXPECT_EQ(s.ToVreg(a0), s.ToVreg(s[0]->OutputAt(0)));
+  ASSERT_EQ(2U, s[1]->InputCount());
+  EXPECT_EQ(kX64Add32, s[1]->arch_opcode());
+  EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[1]->InputAt(0)));
+  EXPECT_EQ(s.ToVreg(a0), s.ToVreg(s[1]->InputAt(1)));
+  EXPECT_EQ(s.ToVreg(a1), s.ToVreg(s[1]->OutputAt(0)));
+}
+
+
 // -----------------------------------------------------------------------------
 // Multiplication.