middle-end/69482 - not preserving volatile accesses

middle-end/69482 - not preserving volatile accesses

The following addresses a long standing issue with not preserving
accesses to non-volatile objects through volatile qualified
pointers in the case that object gets expanded to a register.  The
fix is to treat accesses to an object with a volatile qualified
access as forcing that object to memory.  This issue got more
exposed recently so it regressed more since GCC 11.

	PR middle-end/69482
	* cfgexpand.cc (discover_nonconstant_array_refs_r): Volatile
	qualified accesses also force objects to memory.

	* gcc.target/i386/pr69482-1.c: New testcase.
	* gcc.target/i386/pr69482-2.c: Likewise.