(please try to convince your mailer to use something other than
Content-Type: application/octet-stream for a patch)
On Tue, 21 Nov 2017, Dominik Inführ wrote:
this patch tries to extend tree-ssa-dce.c to remove unnecessary
new/delete-pairs (it already does that for malloc/free). Clang does it
too and it seems to be allowed by
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3664.html. I’ve
bootstrapped/regtested on aarch64-linux and x86_64-linux.
In clang, they (i.e. more or less the authors of the paper you mention)
went through the trouble of introducing __builtin_operator_new
specifically so not all calls to operator new were affected, but
essentially only the calls to the global operator new that come from new
expressions or from std::allocator. This appears to be a deliberate change
between N3537 and N3664, although I did not find the rationale.
So you might want to check with the committee if optimizing more calls is
ok.
--
Marc Glisse
