This bug is a follow-on to Bug 27318 Comment 10. sysdeps/x86/configure.ac incorrectly makes one call to AC_CACHE_CHECK to set three variables: libc_cv_include_x86_isa_level, libc_cv_have_x86_lahf_sahf, and libc_cv_have_x86_movbe. This has the consequence that the latter two variables do not get set whenever the first variable's value is loaded from cache. Then, the later tests using those variables fail because the test arguments are unquoted and the variables are unset. Attached is a patch that refactors the checks for LAHF/SAHF and MOVBE instruction support into separate AC_CACHE_CHECK calls so that the variables are defined even when libc_cv_include_x86_isa_level is cached. I will also submit the patch to the libc-alpha@sourceware.org list.
Created attachment 13498 [details] patch
Fixed on 2.35.