Address comment.

Ping.

Looking at this again and with trunk, I'm seeing two failing tests with a small change inlined:

Added tests, and corrected the definition of the rdhwr instruction.

Actually include the expansion pass.

Moved pass to after the scheduler and machine block placement.
Normalized the probabilities for the successors of modified basic blocks for sanity purposes.

In D47829#1124040, @efriedma wrote:

Is this something which is actually useful to control? From your description, you want to add the flag to clang not because you actually want to use it, but just because you can't figure out how to pass the right flags to your clang build.

If it is useful, it should be implemented as a function attribute, not a global flag.

Modify implementation to produce a function attribute.

LGTM with nit addressed.

Rebase to master.

In D48006, you can see the change for the MIPS specific assembly scrubbing to accept inline assembly. I have also included some example output of the changes of that revision. Since the blank lines around the inline assembly are not scrubbed, FileCheck fails the test case with:

Ping.

Ping.

Please rebase this.

Actually add some tests.

Add tests.

Edit the summary so that rather that it says:

LGTM.

The legalization of unsigned i128 addition (rL334094 for the test) looks strange to me in that the determination of the overflow from the first addition is done with setccs. They appear to be originating from the expansion of setcc of an illegal type.

This particular case is not quite testable, as GPR64s are only available when we have 64 bit registers. Adding GPR_64 predicates to these instructions is somewhat overkill, but does simplify fixing up the scheduler models later.

LGTM.

I take it that this patch is dependent on D47703 ?

Add tests.

Address review comments.

Ping.

Address review comments.