Merged r13946 into 3.16 branch.

src/lithium-allocator.h

Index: src/lithium-allocator.h
diff --git a/src/lithium-allocator.h b/src/lithium-allocator.h
index 2953550ae8e879742ed19d0c4a9bba6cfc5bf5af..c7d910a0c4a7336ac55f28019220ed4261fb64a0 100644
--- a/src/lithium-allocator.h
+++ b/src/lithium-allocator.h
@@ -426,8 +426,10 @@ class LAllocator BASE_EMBEDDED {
   Zone* zone() const { return zone_; }
 
   int GetVirtualRegister() {
-    if (next_virtual_register_ > LUnallocated::kMaxVirtualRegisters) {
+    if (next_virtual_register_ >= LUnallocated::kMaxVirtualRegisters) {
       allocation_ok_ = false;
+      // Maintain the invariant that we return something below the maximum.
+      return 0;
     }
     return next_virtual_register_++;
   }