[turbofan] only use two gaps

test/unittests/compiler/register-allocator-unittest.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/pipeline.h"
 #include "test/unittests/compiler/instruction-sequence-unittest.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 283 matching lines @@
   // values[0] will be split in the second half of this instruction.
   // Models Intel mod instructions.
   EmitOI(Reg(0), Reg(p_0, 1), UniqueReg(p_1));
   EmitI(Reg(values[0], 0));
   EndBlock(Last());
 
   Allocate();
 }
 
 
+TEST_F(RegisterAllocatorTest, SplitBeforeInstruction2) {
+  const int kNumRegs = 6;
+  SetNumRegs(kNumRegs, kNumRegs);
+
+  StartBlock();
+
+  // Stack parameters/spilled values.
+  auto p_0 = Define(Slot(-1));
+  auto p_1 = Define(Slot(-2));
+
+  // Fill registers.
+  VReg values[kNumRegs];
+  for (size_t i = 0; i < arraysize(values); ++i) {
+    values[i] = Define(Reg(static_cast<int>(i)));
+  }
+
+  // values[0] and [1] will be split in the second half of this instruction.
+  EmitOOI(Reg(0), Reg(1), Reg(p_0, 0), Reg(p_1, 1));
+  EmitI(Reg(values[0]), Reg(values[1]));
+  EndBlock(Last());
+
+  Allocate();
+}
+
+
 TEST_F(RegisterAllocatorTest, NestedDiamondPhiMerge) {
   // Outer diamond.
   StartBlock();
   EndBlock(Branch(Imm(), 1, 5));
 
   // Diamond 1
   StartBlock();
   EndBlock(Branch(Imm(), 1, 2));
 
   StartBlock();
@@ skipping 148 matching lines @@
   EmitI(Reg(c));
   EmitI(Reg(to_spill));
   EndBlock(Last());
 
   Allocate();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8