The !ENABLE(COMPUTED_GOTO_OPCODES) build of the C loop LLINT reveals the unused piece of LLINT code for sanitizeStackForVM() was still being built in. In the computed got case, the sanitizeStackForVM() code only results in some unused code in CLoop::execute() and an extra local label which is harmless. In the non-computed goto case, it results in a case statement for an unknown opcode named "sanitizeStackForVM". This results in a build failure. The fix is simply to exclude the unused LLINT sanitizeStackForVM() from the C loop build. Patch coming.
Created attachment 221102 [details] the patch.
Thanks for the review. Landed in r161975 on the jsCStack branch: <http://trac.webkit.org/r161975>.