[optimizing] Don't rely on the verifier for String.<init>.

Continue work on cutting the dependency on the verifier.

Change-Id: I0f95b1eb2e10fd8f6bf54817f1202bdf6dfdb0fe
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index ddaa60d..bcf2444 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -4792,6 +4792,18 @@
   LOG(FATAL) << "Unreachable";
 }
 
+void LocationsBuilderX86_64::VisitFakeString(HFakeString* instruction) {
+  DCHECK(codegen_->IsBaseline());
+  LocationSummary* locations =
+      new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kNoCall);
+  locations->SetOut(Location::ConstantLocation(GetGraph()->GetNullConstant()));
+}
+
+void InstructionCodeGeneratorX86_64::VisitFakeString(HFakeString* instruction ATTRIBUTE_UNUSED) {
+  DCHECK(codegen_->IsBaseline());
+  // Will be generated at use site.
+}
+
 void CodeGeneratorX86_64::Load64BitValue(CpuRegister dest, int64_t value) {
   if (value == 0) {
     __ xorl(dest, dest);