On arm-vx7r2, the uses of as.load() as initializer get SRAed, so the
padding bits in the tests are not what we might expect from full-word
struct copies.
I tried adding a function to perform bitwise copying, but even taking
the as.load() argument by const&, we'd still construct a temporary
with SRAed field-wise copying. Unable to find another way to ensure
we wouldn't get a temporary, I went for disabling SRA.
for libstdc++-v3/ChangeLog
* testsuite/29_atomics/atomic/compare_exchange_padding.cc:
Disable SRA.
dcf0bd14cd