> > On Oct 31, 2016, at 5:28 PM, Bill Schmidt <wschm...@linux.vnet.ibm.com> wrote: > > The other way would be to require a specific option on the command line > to use the new dispatch mechanism. When the option is present, we would > predefine a macro such as __PPC_FAST_VECTOR__, which would then gate the > usage in altivec.h and overload.h. Use of #pragma GCC target to change > the availability of Altivec, VMX, P8-vector, etc. would also be disallowed > when the option is present. This has the advantage of always generating > correct code, at the cost of requiring a special option before anyone > can leverage the benefits of early vector expansion. That's unfortunate, > but I suspect it's the best we can do.
Though I suppose we could require the option to turn off the new dispatch mechanism, and document the change in gcc7/changes.html. A little irritating for people already using the pragma support, but I really expect this wouldn't affect many people at all. -- Bill Bill Schmidt, Ph.D. GCC for Linux on Power Linux on Power Toolchain IBM Linux Technology Center wschm...@linux.vnet.ibm.com
