diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index f15342b487..e387088359 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -227,7 +227,6 @@ void StubCache::GenerateProbe(MacroAssembler* masm,
 
   // Check scratch and extra registers are valid, and extra2 is unused.
   ASSERT(!scratch.is(no_reg));
-  ASSERT(!extra.is(no_reg));
   ASSERT(extra2.is(no_reg));
 
   // Check that the receiver isn't a smi.
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 8b7fb45d77..24609bf642 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -291,7 +291,6 @@ void StubCache::GenerateProbe(MacroAssembler* masm,
 
   // Check scratch register is valid, extra and extra2 are unused.
   ASSERT(!scratch.is(no_reg));
-  ASSERT(extra.is(no_reg));
   ASSERT(extra2.is(no_reg));
 
   // Check that the receiver isn't a smi.