[PATCH] D21143: Include SelectionDAGISel in the opt-bisect process

[Justin Bogner via llvm-commits]

Andy Kaylor <andrew.kaylor at intel.com> writes:
> andrew.w.kaylor created this revision.
> andrew.w.kaylor added a reviewer: bogner.
> andrew.w.kaylor added a subscriber: llvm-commits.
> andrew.w.kaylor set the repository for this revision to rL LLVM.
>
> This patch allows the SelectionDAGISel pass to be put into
> CodeGenOpt::None mode in response to the opt-bisect-limit command line
> option in addition to the OptimizeNone function attribute (the
> skipFunction() call checks both of these conditions).
>
> See D19172 for details on the opt-bisect implementation.
>
> I am checking to see if the optimization level is already
> CodeGenOpt::None before calling the skipFunction() method in order to
> avoid introducing test failures in two lit tests which verify that no
> pass is "skipped" by the optnone or opt-bisect options that is
> otherwise run at -O0.  Calling skipFunction at -O0 wouldn't actually
> change this pass' behavior, but it would generate a debugging message
> indicating that the pass was being skipped.

I haven't been paying attention to the opt-bisect stuff, but this looks
consistent / like it'll do the right thing. Long term we might want to
clean up how SDAGISel deals with opt levels, but that shouldn't block
anything here.

LGTM. It'd be nice if it came with a test though - Do we have a good way
to test opt-bisect?

> Repository:
>   rL LLVM
>
> http://reviews.llvm.org/D21143
>
> Files:
>   lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
>
> Index: lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
> ===================================================================
> --- lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
> +++ lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
> @@ -444,7 +444,7 @@
>    TM.resetTargetOptions(Fn);
>    // Reset OptLevel to None for optnone functions.
>    CodeGenOpt::Level NewOptLevel = OptLevel;
> -  if (Fn.hasFnAttribute(Attribute::OptimizeNone))
> +  if (OptLevel != CodeGenOpt::None && skipFunction(Fn))
>      NewOptLevel = CodeGenOpt::None;
>    OptLevelChanger OLC(*this, NewOptLevel);
>