I've now added a configure test for valgrind/memcheck.h, and I've added code to testsuite/memxor-test.c to use valgrind client requests to tell it the start and end of the src and dst areas.

I've also added the flag --partial-loads-ok=yes to the VALGRIND variable in testsuite/Makefile.in. I usually run valgrind with the invocation

make check EMULATOR='$(VALGRIND)'

Without that flag, I get tons of warnings for both x86_64/memxor.asm and memxor.c.

It would make sense to add similar client requests to more testcases.

Regards, /Niels