[PATCH] D11393: [X86] Allow X86::COND_NE_OR_P and X86::COND_NP_OR_E to be reversed.
Cong Hou via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 28 11:13:36 PST 2016
On Wed, Jan 27, 2016 at 5:10 PM, Xinliang David Li <davidxl at google.com>
> Cong, can you add a comment for the new test case?
> On Wed, Jan 27, 2016 at 5:09 PM, David Kreitzer
> <david.l.kreitzer at intel.com> wrote:
> > DavidKreitzer added inline comments.
> > ================
> > Comment at: llvm/trunk/test/CodeGen/X86/fp-une-cmp.ll:51
> > @@ +50,3 @@
> > +; CHECK: %bb1
> > +; CHECK: jmp
> > +;
> > ----------------
> > davidxl wrote:
> >> DavidKreitzer wrote:
> >> > If we invert the compound branch at the end of the entry block and
> place bb1 before bb2, we can eliminate the jmp at the end of bb1. Do you
> know why that isn't happening?
> >> >
> >> The test case is explicitly added to test the ability for
> MachineBlockPlacement to break the topological order and reorder BB2 ahead
> of BB1 (BB1 is ahead of BB2 in source order) -- look at the profile
> annotation that BB1 is a really cold block -- this reordering is not
> possible without this patch.
> >> See also discussions in
> > Thanks for the explanation! I missed the profile annotation - Please
> ignore my comment on this one.
> > Repository:
> > rL LLVM
> > http://reviews.llvm.org/D11393
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