Previously this took a reference to a map and returned a bool to say
whether it succeeded. We can return a StringMap instead, as all callers
but 1 simply iterated the map if the bool was true, and passed in empty
maps as the starting point.
lldb's lit-cpuid did specifically check whether the call failed, but due
to the way the x86 routines work this works out the same as checking if
the returned map is empty.
The forwarding header is left in place because of its use in
`polly/lib/External/isl/interface/extract_interface.cc`, but I have
added a GCC warning about the fact it is deprecated, because it is used
in `isl` from where it is included by Polly.
Add a new lit-cpuid tool that detects CPU features used by some of
the tests, and use it to populate available_features in lit. For now,
this means that the test for MM/XMM register read will be run only
when the host CPU support SSE instruction set. However, this is going
to make it possible to introduce additional tests relying on AVX.
Differential Revision: https://reviews.llvm.org/D61073
llvm-svn: 359303
