On Sat, Jan 19, 2019 at 12:25 AM Martin Sebor <mse...@gmail.com> wrote:
>
> Some of the -Warray-bounds and -Wrestrict tests are prone to failing
> on targets like arm-eabi and others that use different parameters to
> decide which memcpy calls should be folded to MEM_REF (those that do
> are copies of small power-of-two sizes where the power tends to vary
> from target to target and may be as little as 1). The failures then
> waste the time of those who maintain those secondary targets reporting
> failures (see * below), as well as those who wrote the tests debugging
> the problems and working around them.
>
> To reduce this effort (and ideally avoid these regressions going
> forward) the attached patch adds a new effective-target to the test
> harness: fold_memcpy_N. It detects the target's willingness to fold
> memcpy call of the given size (N). While testing this with the arm
> cross-compiler I also tweaked the tests that #include standard
> headers to only do so when __has_include says the header exists.
> This lets the tests pass even when using a cross-compiler without
> library headers installed (my default MO). If/when the warnings
> are improved to detect the problems regardless of the folding as
> I'm hoping to eventually do, this new effective-target feature
> can be removed.
But all the memcpy folding does is see whether the target can
access unaligned {2,4,8,<max-int-mode-size>} memory. So
a effective target unaligned_move_{2,4,8...} would be better and
possibly useful in other contexts? memcpy folding might be indeed
a nice vehicle to test this property.
Thus, I guess I'm only asking to rename the effective target keyword.
Btw, new effective targets need documenting in sourcebuild.texi
Richard.
> Martin
>
> [*] https://gcc.gnu.org/ml/gcc-patches/2019-01/msg01056.html
